List of Iwanuma Project Papers (by Order of topics)
1 Gero K, Aida J, Shirai K, Kondo K, Kawachi I: Dispositional optimism and disaster resilience: A natural experiment from the 2011 Great East Japan Earthquake and tsunami. Soc Sci Med.
2021 Mar; 273:113777. doi: 10.1016/j.socscimed.2021.113777.
2 Sasaki Y, Aida J, Tsuji T, Koyama S, Tsuboya T, Saito T, Kon do K, Kawachi I: Pre-disaster social support is protective for onset of post-disaster depression: Prospective study from the Great
East Japan Earthquake & tsunami. Sci Rep. 2019 Dec 19;9(1):19427. doi:10.1038/s41598-019-55953-7.
3 Inoue Y, Stickley A, Yazawa A, Aida J, Kawachi I, Kondo K, Fujiwara T: Adverse childhood experiences, exposure to a natural disaster and posttraumatic stress disorder among survivors ofthe 2011 Great East Japan Earthquake and tsunami. Epidemiol Psychiatr Sci. 2019 Feb;28(1):45-53. doi:10.1017/S2045796017000233. Epub 2017 May 15.
4 Hikichi H, Aida J, Tsuboya T, Kondo K, Kawachi I: Can community social cohesion prevent posttraumatic stress disorder in the aftermath of a disaster? A natural experiment from the 2011
Tohoku Earthquake and tsunami. Am J Epidemiol. 2016 May 15;183(10):902-10. doi:10.1093/aje/kwv335. Epub 2016 Mar 29.
5 Hikichi H, Kondo K, Aida J, Kondo N: Social capital in disaster medicine Group interviews with public health nurses working in areas stricken by the Tohoku earthquake. Japanese Journalof Disaster Medicine 2015;20 (1):51-56.
6 Hikichi H, Sawada Y, Tsuboya T, Aida J, Kondo K, Koyama S, Kawachi I: Residential relocation and change in social capital: A natural experiment from the 2011 Great East Japan
Earthquake and tsunami. Sci Adv. 2017 Jul 26;3(7): e1700426. doi:10.1126/sciadv.1700426
7 Li X, Buxton OM, Hikichi H, Haneuse S, Aida J, Kondo K, Kawachi I: Predictors of persistent sleep problems among older disaster survivors: a natural experiment from the 2011 Great East
Japan Earthquake and tsunami. Sleep. 2018 Jul 1;41(7): zsy084. doi:10.1093/sleep/zsy084.
8 Zhang W, Tsuji T, Yokoyama M, Ide K, Aida J, Kawachi I, Kondo K: Increased frequency of participation in civic associations and reduced depressive symptoms: Prospective study of older
Japanese survivors of the Great Eastern Japan Earthquake. Soc Sci Med. 2021 Mar 8; 276:11 3827. doi: 10.1016/j.socscimed.2021.113827.
9 Tsuji T, Sasaki Y, Matsuyama Y, Sato Y, Aida J, Kondo K, Kawachi I: Reducing depressive symptoms after the Great East Japan Earthquake in older survivors through group exercise
participation and regular walking: a prospective observational study. BMJ Open. 2017 Mar 3;7(3): e013706. doi:10.1136/bmjopen-2016-013706.
10 Hikichi H, Aida J, Matsuyama Y, Tsuboya T, Kondo K, Kawachi I: Community-level social capital and cognitive decline after a natural disaster: A natural experiment from the 2011 Great
East Japan Earthquake and tsunami. Soc Sci Med. 2018 Sep:111981. doi: 10.1016/j.socscimed.2018.09.057.
11 Aida J, Hikichi H, Matsuyama Y, Sato Y, Tsuboya T, Tabuchi T, Koyama S, Subramanian SV, Kondo K, Osaka K, Kawachi I: Risk of mortality during and after the 2011 Great East Japan
Earthquake and tsunami among older coastal residents. Sci Rep. 2017 Nov 29;7(1):16591. doi:10.1038/s41598-017-16636-3.
12 Hikichi H, Tsuboya T, Aida J, Matsuyama Y, Kondo K, Subramani an SV, Kawachi I: Social capital and cognitive decline in the aftermath of a natural disaster: a natural experiment from the2011 Great East Japan Earthquake and tsunami. Lancet Planet Health. 2017 Jun;1(3): e105-e113. doi:10.1016/S2542-5196(17)30041-4.
13 Gero K, Hikichi H, Aida J, Kondo K, Kawachi I: Associations between community social capital and preservation of functional capacity in the aftermath of a major disaster. Am J Epidemiol.
2020 Nov 2;189(11):1369-1378. doi:10.1093/aje/kwaa085.
14 Koyama S, Aida J, Kawachi I, Kondo N, Subramanian SV, Ito K, Kobashi G, Masuno K, Kondo K, Osaka K: Social support improves mental health among the victims relocated to temporary
housing following the Great East Japan Earthquake and tsunami. Tohoku J Exp Med. 2014 Nov;234(3):241-7. doi:10.1620/tjem.234.241.
15 Kawachi I, Aida J, Hikichi H, Kondo K: Disaster resilience in aging populations: lessons from the 2011 Great East Japan Earthquake and tsunami. Journal of the Royal Society of New
Zealand. 2020 Feb 4;50(2):263-278. doi:10.1080/03036758.2020.1722186.
16 Sasaki Y, Tsuji T, Koyama S, Tani Y, Saito T, Kondo K, Kawachi I, Aida J: Neighborhood ties reduced depressive symptoms in older disaster survivors: Iwanuma study, a natural experiment.
Int J Environ Res Public Health. 2020 Jan 3;17(1):337. doi:10.3390/ijerph17010337.
17 Gero K, Aida J, Kondo K, Kawachi I: Evaluation of trust within a community after survivor relocation following the Great East Japan Earthquake and tsunami. JAMA Netw Open. 2020
Nov;3(11): e2021166. doi:10.1001/jamanetworkopen.2020.21166.
18 Matsuyama Y, Aida J, Tsuboya T, Hikichi H, Kondo K, Kawachi I, Osaka K: Are lowered socioeconomic circumstances causally related to tooth loss? A natural experiment Involving the 2011
Great East Japan Earthquake. Am J Epidemiol. 2017 Jul 1;186(1):54-62. doi:10.1093/aje/kwx059.
19 Shiba K, Yazawa A, Kino S, Kondo K, Aida J, Kawachi I: Depressive symptoms in the aftermath of major disaster: Empirical test of the social support deterioration model using naturalexperiment. Wellbeing, Space and Society. 2020 Jan 1; 1:100006. doi: 10.1016/j.wss.2020.100006.
20 Tsuboya T, Aida J, Hikichi H, Subramanian SV, Kondo K, Osaka K, Kawachi I: Predictors of depressive symptoms following the Great East Japan Earthquake: A prospective study. Soc Sci
Med. 2016 Jul; 161:47-54. doi: 10.1016/j.socscimed.2016.05.026. Epub 2016 May 20.
21 Tsuboya T, Aida J, Hikichi H, Subramanian SV, Kondo K, Osaka K, Kawachi I: Predictors of decline in IADL functioning among older survivors following the Great East Japan Earthquake: A
prospective study. Soc Sci Med. 2017 Mar;176:34-41. doi: 10.1016/j.socscimed.2017.01.022. Epub 2017 Jan 18.
22 Hikichi H, Aida J, Kondo K, Tsuboya T, Kawachi I: Residential relocation and obesity after a natural disaster: A natural experiment from the 2011 Japan Earthquake and tsunami. Sci Rep.
2019 Jan;9(1):374. doi:10.1038/s41598-018-36906-y.
23 Shiba K, Hikichi H, Aida J, Kondo K, Kawachi I: Long-term associations between disaster experiences and cardiometabolic risk: A natural experiment from the 2011 Great East Japan
Earthquake and tsunami. Am J Epidemiol. 2019 Jun 1;188(6):1109-1119. doi:10.1093/aje/kwz065.
24 Sasaki Y, Aida J, Tsuji T, Miyaguni Y, Tani Y, Koyama S, Matsuyama Y, Sato Y, Tsuboya T, Nagamine Y, Kameda Y, Saito T, Kakimoto K, Kondo K, Kawachi I: Does type of residential housing
matter for depressive symptoms in the aftermath of a disaster? Insights from the Great East Japan Earthquake and tsunami. Am J Epidemiol. 2018 Mar;187(3):455-464.
doi:10.1093/aje/kwx274.
25 Li X, Aida J, Hikichi H, Kondo K, Kawachi I: Association of postdisaster depression and posttraumatic stress disorder with mortality among older disaster survivors of the 2011 Great East
Japan Earthquake and tsunami. JAMA Network Open. 2019;2(12): e1917550. doi:10.1001/jamanetworkopen.2019.17550.
26 Hikichi H, Aida J, Kondo K, Tsuboya T, Matsuyama Y, Subramani an SV, Kawachi I: Increased risk of dementia in the aftermath of the 2011 Great East Japan Earthquake and tsunami. Proc
Natl Acad Sci USA. 2016 Nov 8;113(45):E6911-E6918. doi:10.1073/pnas.1607793113. Epub 2016 Oct 24.
27 Ikeda T, Aida J, Kawachi I, Kondo K, Osaka K: Causal effect of deteriorating socioeconomic circumstances on new-onset arthritis and the moderating role of access to medical care: A
natural experiment from the 2011 Great East Japan Earthquake and tsunami. Soc Sci Med. 2020 Nov;26 4:113385. doi: 10.1016/j.socscimed.2020.113385. Epub 2020 Sep 25.
28 Shiba K, Aida J, Kondo K, Nakagomi A, Arcaya M, James P, Kawachi I: Mediation of the relationship between home loss and worsened cardiometabolic proﬁles of older disaster survivors
by post-disaster relocation: A natural experiment from the Great East Japan Earthquake and tsunami. Health & Place. 2020 Nov 1; 66:102456. doi: 10.1016/j.healthplace.2020.102456.
29 Hikichi H, Aida J, Kondo K, Kawachi I: Persistent impact of housing loss on cognitive decline after the 2011 Great East Japan Earthquake and tsunami: Evidence from a 6-year
longitudinal study. Alzheimers Dement. 2019 Aug;15(8):1009-1018. doi: 10.1016/j.jalz.2019.04.016. Epub 2019 Aug 1.
30 Kino S, Aida J, Kondo K, Kawachi I: Long-term trends in mental health disorders after the 2011 Great East Japan Earthquake and tsunami. JAMA Netw Open. 2020 Aug 3;3(8): e2013437.
doi:10.1001/jamanetworkopen.2020.13437.
31 Shiba K, Hanazato M, Aida J, Kondo K, Arcaya M, James P, Kawachi I: Cardiometabolic proﬁles and change in neighborhood food and built environment among older adults: A naturalexperiment. Epidemiology. 2020 Nov;31(6):758-767. doi:10.1097/EDE.0000000000001243.
32 Shiba K, Kawahara T, Aida J, Kondo K, Kondo N, James P, Arcaya M, Kawachi I: Causal inference in studying the long-term health effects of disasters: Challenges and potential solutions.
Am J Epidemiol. 2021 Mar 17. doi:10.1093/aje/kwab064.
33 Kino S, Aida J, Kondo K, Kawachi I: Persistent mental health impacts of disaster. Five-year follow-up after the 2011 Great East Japan Earthquake and tsunami: Iwanuma Study. J Psychiatr
Res. 2021 Apr; 136:452-459. doi: 10.1016/j.jpsychires.2020.08.016. Epub 2020 Aug 23.
34 Hikichi H, Aida J, Kondo K, Kawachi I. Six-year follow-up study of residential displacement and health outcomes following the 2011 Japan Earthquake and tsunami. Proc Natl Acad Sci U S
A. 2021 Jan 12;118(2): e2014226118. doi: 10.1073/pnas.2014226118.

Iwanuma Project Research Results
Social capital and functional recovery of older adults after theGreat East Japan Earthquake and Tsunami

Editing : Iwanuma Project
Date: July 1, 2021 (March 31, 2022 English version)
Publishing : Division of Social Preventive Medical Sciences, Center for Preventive Medical Sciences, Chiba University
Design : Liberty Area Incorporate

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Social capital and functional recovery of older adults after the Great East Japan
Earthquake and Tsunami

Iwanuma Project
Research Results

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Iwanuma ProjectIwanuma Project Suggestions

The impact of social capital on the physical andmental health of disaster survivors
Growing attention has been focused on the role of social connections (“social capital”) in assisting recovery after natural disasters.
Social capital is thought to be a factor that promotes community resilience after a disaster.
Seven months before the 2011 Great East Japan Earthquake, a survey was conducted on the relationship between social capital andhealth in Iwanuma City, Miyagi Prefecture, Japan. Survivors have been followed since, providing a unique opportunity to study the
impact of social capital on their health.
Through collaboration between the Japan Gerontological Evaluation Study (JAGES), Iwanuma City, and Professor Ichiro Kawachi ofHarvard University's School of Public Health, the Iwanuma Study has contributed to our understanding of the factors that promote
recovery among older disaster survivors.

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OutlineC R O S S

Iwanuma Project

T A L K

Strengthening social capital is a key strategy for disaster preparedness
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Professor, School of Public Health, Harvard University

ICHIRO KAWACHI
Graduated from University of Otago. He received his M.D. from the University of Otago in 1985. After
working as a physician, Dr. Kawachi was awarded his Ph.D. in 1991. Since 1992, he has taught at Harvard
University, where he is currently the John L. Loeb and Frances Lehman Loeb Professor of Social
Epidemiology in the Department of Social and Behavioral Sciences at the Harvard University T.H. Chan
School of Public Health. Kawachi is an elected member of the National Academy of Medicine of the UnitedStates and an Honorary Fellow of the Royal Society of New Zealand.

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Professor, Center for Preventive Medical Sciences, Chiba University;
Head of the Department of Gerontological Evaluation, National Center for Geriatrics and Gerontology

KATSUNORI KONDO
Graduated from Chiba University Graduate School of Medicine in 1983. After working as a physician, Dr.
Kondo became Associate Professor at the Nihon Fukushi University in 1997. After a stint as a Visiting
Research Fellow at the University of Kent at Canterbury (UK) (2000-2001) and then as Professor at Nihon
Fukushi University, he has been the Professor at Chiba University since 2014, and a Head of Department of
the National Center for Geriatrics and Gerontology since 2016 (Cross-Appointment Post). In 2020, he
received the Medical Award of the Japan Medical Association in 2020.

What was your motivation to start
the Iwanuma Project?

capital could help people overcome the damage caused by disasters.

houses, those who lived in communities with high social capital before

heterogeneity of health outcomes following exposure to the same

Disaster preparedness involves stockpiling food, water, medicines, andthe disaster, or who became richer in social capital before and after thetraumatic events. For example, only half of the people who experiencearranging evacuation shelters. Our hypothesis was that resiliencedisaster, were less likely to deterioration. This means thatsevere trauma develop severe post-traumatic stress disorder (PTSD),

Kawachi: Globally, disasters are becoming increasingly severe andarises from peoples' social connections.

strengthening the social capital of a community is an important

while the other half remain relatively asymptomatic. Using machine

strategy for disaster preparedness.

learning, we can identify the characteristics of resilient individuals. This

What have been the mainﬁndings so far?

Kondo: There are dual aspects here: hard disaster preparedness, suchinformation can help focus resources more efﬁciently on people andas building breakwaters, and soft disaster preparedness. One such

communities that are vulnerable to disasters.

example is the development of social capital. The National Institute of

Kondo: We are also working with the National Research Instituteof the impact of disasters on the health of older adults, their recovery,

Kawachi: First, we found a marked increase in cognitive disability and

Health in the United States also provided research grant for thefor Earth Science and Disaster Resilience, Japan, to develop aand the factors that contribute to it.

metabolic syndrome among those who moved into temporary

Iwanuma Project. Was it useful for the United States?

disaster preparedness "visualization" system (see p. 29), which

Kondo: We wanted to demonstrate scientiﬁcally, using data, not justhousing. However, we also found that older adults were more resilient

Kawachi: The valuable lessons learned from the Iwanuma Project areallows you to see which areas are resistant or vulnerable toanecdotally, that social capital or "connections" between people canin terms of mental health. For example, three years after the disaster,useful, not only in Japan but also around the world. For example, wedisasters. This system will be used by residents and local

contribute to disaster preparedness and resilience (recovery from athe majority of people had recovered from their grief, and depression

found that when relocating people to temporary housing, it was best to

governments in workshops for disaster preparedness. We hopemajor shock).

rates in the community had returned to pre-disaster levels.

do so in groups that maintained pre-existing neighborhood relationshipsthat the Iwanuma Project will serve as an opportunity to foster

There was an inconclusive debate in the studies that started after the

Kondo: We observed other health concerns as well, including

to preserve social capital. After learning about the results of the Iwanuma

social capital and connections between residents during normal

disaster about which came ﬁrst—health or social capital—the cause andpost-traumatic stress disorder (PTSD), instrumental activities of daily

Project through The Wall Street Journal, the City of Houston contacted us

times, the signiﬁcance of which has been demonstrated by

the effect. However, Iwanuma City conducted a survey on the healthliving (IADL), and tooth loss. What surprised me was that the greater theand made use of this insight during their response to Hurricane Harvey.

the project.

and social capital of older adults in August 2010, seven months before

damage to the house, the greater the health hazard. However, we werethe earthquake, which gave us a rare opportunity to settle this debate.

also able to identify the factors that alleviated these health hazards.

What was the goal of this plan?

Kawachi: We found that even among people who had suffered difﬁcult

Kawachi: Our goal was to examine whether communities with high social

experiences, such as losing their loved ones and damaging theirfrequent. However, the impact of disasters on older adults is still
poorly understood. After the tragedy of the Great East Japan
Earthquake in March 2011, we have had an invaluable opportunity
through the Iwanuma Research Project to deepen our understanding

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We would like to thank the people of Iwanuma City and everyone who

What are your plans for the future?

cooperated with this project. We are working on a follow-up study in

Kawachi: The next phase of the Iwanuma Project is to understand thecontinued cooperation.

2022 to examine its long-term impact and look forward to your4Outline

M E S S A G E

M E S S A G E
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Professor, Tokyo Medical and Dental University

JUN AIDA
Is a Core Member of the Japan Gerontological Evaluation Study. Since 2020, Dr. Aida has
worked as a Professor in the Department of Oral Health Promotion, Graduate School of Medical
and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan, and Professor in the
Regional Community Development, Liaison Center for Innovative Dentistry, Graduate School of
Dentistry, Tohoku University (Cross-Appointment, until May 2021). He has specialized in social
epidemiology and dental public health.

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Iwanuma Project

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Former Mayor of Iwanuma CityTSUNEAKI IGUCHI
Graduated from Miyagi University of Education, worked in a tutoring school, and was elected to
the Iwanuma City Council at the age of 25. He served as the Chairman of the Iwanuma City
Social Welfare Council for seven consecutive terms. After serving as Council Chairman, he waselected mayor, and served four terms for 16 years. During this time, he also served as the Vice
President of the Japan Association of City Mayors. Mr. Iguchi was awarded Order of the RisingSun, Gold Rays with Neck Ribbon for his distinguished service to local government. Currently,
he is a Visiting Professor at the Tohoku Fukushi University, an Interim Member of the Social
Security Council, and Director of the Millennium Hope Hills Association.

We would like to connect the value of the preearthquake data with internationally useful evidence.

Many results of the Iwanuma Project provide lessons
that will guide us in the "Era of Disasters."

The Iwanuma Project started in 2007 when the Iwanuma City Care

The factors that contribute to protecting the health of disaster

After taking up the post of Mayor, I established the goal of "Building ameeting of village representatives, including women and young

and Welfare Division, together with the Department of International

survivors and promoting their recovery are not clear.

“Healthy and Happy City." As part of this effort, we conducted a healthpeople. We were able to establish commercial facilities necessary for

and Community Oral Health, Graduate School of Dentistry, Tohoku

Most disaster research has been conducted after disasters haveand lifestyle survey for all people over the age of 65 under the guidance

daily life because the six affected communities were relocated en

University, jointly implemented a model project for preventive care,occurred. Few studies have used data on pre-disaster conditions. As

of Professors Ken Osaka and Jun Aida of Tohoku University. Seven months

masse to a single location. We also promoted the development of theled by Professor Ken Osaka, under whom I worked with his

a result, the Iwanuma Project has been recognized in Japan and thelater, the Great East Japan Earthquake struck 48% of the Iwanuma City

Millenium Hope Hills, which was named as a symbol of reconstruction.

department at the time.

US as a valuable source of pre-earthquake data. Therefore, we havearea, claiming many victims. There were no other surveys with data on the

Many people throughout Japan participated in a tree-planting

The JAGES 2010 survey was conducted before the earthquake, which

received funding to continue research related to health andhealth status of older adults and people’ s connections before theceremony featuring broad-leaved trees, used as symbols for abecame the baseline for the Iwanuma Project, and follow-up surveys

disasters. This project is being conducted with the cooperation ofdisaster. The Iwanuma Project was created based on these data.

torch-relay course for the Reconstruction Olympics. The forest on thehave continued every three years.

citizens and the Iwanuma local government. We will continue ourIn the process of reconstruction, we decided to protect lives, work

hill will serve as a breakwater in addition to the concrete embankment.

In addition to the direct risk of injury and death, disasters also

efforts to produce results that will be useful to the people ofquickly, and become self-reliant. Iwanuma City was able to achieve thePillars and memorabilia from houses that were washed away were also

destroy houses, farmlands, and factories. This causes damage to jobs

Iwanuma City and generate helpful evidence for global

fastest mass relocation among the affected areas. We did not apply aused. We became a top runner in the reconstruction process since weand the economy. Residential relocation and migration also change

communities.

lottery when transferring people from evacuation shelters to temporary

formulated a recovery plan early and worked to implement it. Manysocial relationships. From the viewpoint of social determinants of

We look forward to your continued support and encouragement.

housing and group relocation. Each community was relocatedresults were announced from the Iwanuma Project, which wehealth, these changes in the physical and social environment are

individually because we wanted to protect the bonds between

communicated with the assistance of teachers. There are many lessons

believed to have a signiﬁcant impact on health.

residents. The decision on what kind of town to build was made at a

to be learned that will guide us in the "Era of Disasters."

6Outline

Description

Research Design
Kesennuma
City

Iwanuma location and terrain

Kurihara City

Located approximately 17.6 km south of Sendai, Miyagi Prefecture, the city’ seastern border is the Paciﬁc coast and the western border is mountainous. Sendai
Airport was established, followed by the development of an adjacent industrial
area. Population of approximately 44,000 / area of approximately 60km2.

ShikamaTown
Ohira
Village
Taiwa Town

● Over ~48% of the city area ﬂooded by the tsunami

Aoba Ward● Severe land subsidence / 8% of city area below sea level

Zao Town● Extensive damage to agricultural lands andShichikashuku
Town

Minamisanriku
Town

Shiroishi
City

WakuyaTown

The more severe the damage caused by the disaster

Ishinomaki City
Onagawa Town

Osato
Town

HigashiMatsushima Matsushima
City
Town

KakudaCity

Yamamoto
Town

Research design for JAGES and Iwanuma Project

Marumori
Town

JAGES2010

JAGES2016

JAGES2013(Questionnaire)(Questionnaire)・ Iwanuma
・・
Follow up
・(Longitudinal
・Other local Study)

・ Iwanuma
・・・・Other local

govts.

Most of the previous research on earthquakes was completed within a few years after the earthquake; in this project, wewere able to analyze survey results with a long follow-up period of approximately eight and a half years after the earthquake.

・ Iwanuma
・ Iwanuma
・・(Extent of damage, etc.)
・・
Follow up
Follow up(Longitudinal ・Cross-sectional (Longitudinal ・Study)
Analysis・Other local Study)
・Other local

Earthquake-related
items

govts.

No previous data

Existing previous data

3.11
Great East Japan
Earthquake

With data
With data

Health Status/ Function

Time ﬂow

High social capital
Low social capital(Event behind decline of health)govts.

TargetAll older adults (65 years old and over)living in Iwanuma City.

Method 1

JAGES
2010

JAGES
2013

With data

With data

govts.

Interviews withpublic health nurses
and otherGreat East Japan Earthquake

While previous research on earthquakes mostly focused on mental health, this project was able to analyze the effects of the disasteron physical functioning, cognitive deterioration, and social participation of the older population in particular.

JAGES2019(Questionnaire)

Veriﬁcation of Hypothesis 2

Few previous studies have examined the impact of earthquakes
on older adults; however, this project was able to shed light on this topic

Impact on Physical Functionand Social Participation(Questionnaire)

Iwanuma Project

Information on disaster victims surveyed before the earthquake

Impact on Older Adults

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led to good health (ADL/IADL) two and a half

WatariTown

Long Follow-up Period

Natural Experimentaccess to medical care, etc.), the worse the health status

Longitudinal Study and Interview Survey

It was possible to create a system to obtain accurate follow-up surveys and information in cooperation with Iwanuma City.

This Study

Higher social capital before the earthquake

Iwanuma City

Survey System

Longitudinal(e.g., loss of family and friends, damage to house, reduced(ADL/IADL) after the disaster (2013, 2016, 2019).

Rifu
Town Shiogama City
Tagajo City Shichigahama Town

In August 2010, seven months before the Great East Japan Earthquake, the Japan Gerontological Evaluation Study (JAGES) conducted a survey ofall older adults in Iwanuma City.
The survey included data on social capital and health, which made it possible to compare situations before and after the disaster, providing new
insights into the causal relationship between social capital and health.

Cross-sectional

Hypothesis 2

Miyagino Ward

Natori City
MurataTown
Shibata
Town

OgawaraTown

This project was possible due to the existenceof data from a survey of all older adults conductedseven months before the earthquake

Existence of Survey Data

Hypothesis 1

Wakabayashi
Ward

Kawasaki Town

● Approximately 5400 homes damaged

200 companies in the industrial park

Izumi Ward

Sendai City

Taihaku Ward

● Six coastal villages destroyed, 187 dead/missing

Did social capital have an impact on the functional deterioration and recoveryof older adults after the Great East Japan Earthquake?

Kami Town

TomiyaCity(Largest affected municipalities)

Tome City

Osaki City

Iwanuma damage assessment

Previous Research

Iwanuma Project

JAGES
2016

JAGES
2019

Comparison of health pre- and post-earthquake

Postal distribution and on-site collection of the JAGES
questionnaire (including earthquake-related items,
Iwanuma City version) for 5,058 respondents of the
JAGES 2010 after the earthquake (2013, 2016, 2019)

Method 2

Interview with public health nurses, local welfare ofﬁcers,
Council of Social Welfare staff, residents, etc.

2010

2011
3.11

2013

2016

2019
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Published Papers [ I n d e x ]
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Pre-Earthquake

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Pre- and Post-Earthquake

Iwanuma Project
Published Papers 2021.6

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Social support before the earthquake reduced the risk ofdeveloping depressive symptoms by 30%
Unexpected higher risk of PTSD among people who did notexperience early life adversity
Pre-disaster community social ties prevent incident
posttraumatic stress disorder (PTSD)
Bonding, bridging and linking social capital –Qualitative study of public health nurses•Post-traumatic stress disorder (PTSD) after the earthquake became more pronounced in those
who did not experience adverse childhood experiences•Relationship between pre-disaster community social ties, disaster experiences, and the risk ofdeveloping PTSD
•Clarifying human connections among public health nurses, external organizations, and disastersurvivor groups

7 Predictors of sleep problems in disaster survivors•People facing ﬁnancial hardship after a disaster had up to 1.47 times higher risk of sleep disorders

Increased participation in exercise and hobby groups help to
8 reduce depressive symptoms in disaster survivors
Physical activity helps to prevent depressive symptoms in
9 older disaster survivors
Community-level social capital mitigates progression of
10 cognitive disability after a disaster
Depressive symptoms and higher mortality on the day of
11 the disasterIndividual-level social ties mitigate post-earthquake
12 progression of cognitive disability
Community social capital helps to preserve functional
13 independence in older survivors
Positive effects on mental health of group relocation into
14 temporary housing•Increased participation in exercise and hobby groups reduces depressive symptoms

15 Review article: Disaster resilience in older populations•Increasing levels of symptoms of dementia depending on the severity of damage to housing

Socializing with neighbors post-earthquake reduces•Relationship between changes in neighborhood relationships and the degree of severity ofdepressive symptoms

Relocation affects social relationships in areas receiving•Changes in community relations (trust) among nonrelocated Iwanuma City residents

Worsening ﬁnancial status increases risk of tooth loss

•People severely affected by the earthquake were more likely to lose their teeth

Decreased social capital does not explain post-disaster•Decrease in social support and social capital after the disaster does not explain the increase indepressive symptoms among disaster survivors

18 after disasterWe have classiﬁed the published papers into four phases of the disaster:•Social support before the earthquake reduced the risk of developing depressive symptoms by 30%•The relationship between methods of relocation and social ties

17 displaced survivors

disaster and after the disaster – on the physical and mental health of survivors.

•Optimists have fewer depressive and post-traumatic stress symptoms after a disaster6 Maintaining social ties through group relocation

16 depressive symptoms

The Iwanuma Project focuses on the impacts of social capital – both preceding the

19 increased depressive symptoms
Post-Earthquake"Pre-Earthquake," "Pre- and Post-Earthquake,""Post-Earthquake," and "Long-term Effects."

1 Optimists are more resilient after the earthquake•Relationships with changes in depressive symptoms pre- and post-disaster•Social ties mitigate the impact of disaster experiences on post-disaster cognitive disability•Mortality risk during disaster is four times higher for those with depressive symptoms.
Post-disaster mortality risk reduced by about half through interaction with friends.
•Social ties mitigate the progression of dementia due to a disaster•In areas with high social participation, the negative health impact of housing damage was reduced•Survivors who underwent group allocation to temporary housing were signiﬁcantly more likely toreport receiving social support than those who underwent lottery allocation

20 Predictors of worsened depressive symptoms after disaster
Access to medical care is key to preserving functional

21 independence•Relationship between disaster experiences and decline in functional independence

Residential relocation linked to increased obesity due to

22 changed food environmentLong-term effects of total destruction of one’ s house on•Degree of property damage and changes in cardiometabolic proﬁles before and after theearthquake (2010–2013)24 of depression

Relocation to prefabricated housing doubled the risk

•Odds ratios of depression according to type of post-disaster housing

25 Post-disaster mental health as a predictor of mortality•Post-disaster depressive symptoms, post-traumatic stress disorder (PTSD), and mortality rates

23 cardiometabolic risks

Housing damage is associated with increased cognitive

26 disability•Association between severity of housing damage and increased cognitive disability score

Increased risk of developing arthritis associated with

27 disaster trauma

28 Risk of increased BMI due to relocation to temporary housing
Persistent impact of housing loss on cognitive disability•Empirical evidence on the relationship between property damage/relocation to temporary
housing and increased BMI

Long-Term Impact

29 6 years after disaster•Persistent impact of housing loss on cognitive disability 6 years after disaster

30 Long-term trends in mental health after disaster•Trajectories of post-traumatic stress symptoms and depression, 2.5 and 5.5 years after the disaster•Individual symptoms of mental illness changed pre- and post-earthquake; however, prevalence in community did not

31 Relocation linked with increased cardiometabolic risks•Correlation between neighborhood environment and lifestyle-related diseases

Long-term relationship between a traumatic experience•The long-term health impacts of an earthquake may have been underestimatedPredictors of persistent mental health problems 6 years•Predictors of persistent versus delayed post-traumatic stress symptoms•Unemployment and deterioration of ﬁnancial status due to the earthquake affect persistent and delayed onset PTSS

6-year followup study of the health impacts of residential•Group relocation to disaster relief housing increases the risk of obesity and depression

32 and health

33 after disaster34 relocation

Pre-Earthquake Papers on the effects of pre-earthquake factors on post-earthquake healthPre- and Post-Earthquake Papers on the effects of the changes in factors from before toafter the earthquake on post-earthquake health

Post-Earthquake Papers on the effects of post-earthquake factors on healthLong-Term Impact Papers on the effects of factors on health more than 5.5 years after the earthquake

Essay1 Optimists are more resilient after the earthquake

Pre-earthquake

3 Unexpected higher risk of PTSD among people who did not experience early life adversity

6

0.7

0.5
0.4
0.3
0.2

(n=580)Experienced adversity

Half destroyed

Mostly destroyed

Severity of housing damage

Destroyed

Gero K, Aida J, Shirai K, Kondo K, Kawachi I: Dispositional optimism anddisaster resilience: A natural experiment from the 2011 Great East Japan
Earthquake and tsunami. Soc Sci Med. 2021 Mar; 273:113777. doi:
10.1016/j.socscimed.2021.113777.

Dispositional optimism - the general belief that good things will happen - is considered a key asset for the preservation of mental health after a traumatic life event. However, it has been hypothesized that inextreme situations such as major disasters where positive expectations cannot overcome the grim reality on the ground, being optimistic might be a disadvantage. Gero et al. (2021) tested this mismatch
hypothesis, exploring whether higher pre-disaster dispositional optimism is associated with higher posttraumatic stress (PTS) and depressive symptoms among 962 individuals who experienced the 2011
Great East Japan Earthquake and Tsunami. The results show that higher pre-disaster dispositional optimism was associated with lower odds of developing depressive and PTS symptoms 2.5 years after theearthquake. Further, high dispositional optimism buffered the adverse impact of housing damage on depressive symptoms, but not on PTS symptoms. In contrast to the mismatch hypothesis, the results
suggest that dispositional optimism is a resilience resource among survivors of a disaster.

support before the earthquake reduced the risk of
2 Socialdeveloping depressive symptoms by 30%

Pre-earthquake

Social support before the earthquake reduced the risk of developing depressive symptoms by 30%

1.00

3
2

0.50

Pre-earthquake

Pre-earthquake

Damage to a house

Loss of a relative/friend

Yes (n = 1,743)

No (Standard) (n = 317)

Pre- and Post- Earthquake

Relationship between pre-disaster community social ties, disaster experiences, and the risk of developing PTSD

2.5

*p < 0.05; **p < 0.01; ***p < 0.0001

2.0
1.94***

1.5

1.64***

1.0
0.87*

0.75**

0.0
0.00

Inoue Y, Stickley A, Yazawa A, Aida J, Kawachi I, Kondo K, Fujiwara T: Adverse childhood
experiences, exposure to a natural disaster and posttraumatic stress disorder among
survivors of the 2011 Great East Japan Earthquake and tsunami. Epidemiol Psychiatr Sci.
2019 Feb;28(1):45-53. doi:10.1017/S2045796017000233. Epub 2017 May 15.

community social ties prevent incident posttraumatic stress disorder
4 Pre-disaster(PTSD)

0.5

Sasaki Y, Aida J, Tsuji T, Koyama S, Tsuboya T, Saito T, Kon do K, Kawachi I: Pre-disaster social support is protective for
onset of post-disaster depression: Prospective study from the Great East Japan Earthquake & tsunami. Sci Rep. 2019
Dec 19;9(1):19427. doi:10.1038/s41598-019-55953-7.

* Of the people included in each group: Damage to house Yes/
Experienced adversity during Childhood Yes (n=30); Yes / No (n=13);
No / Yes (n=320); No / No (n=217). Lost loved ones Yes / Experienced
Adversity during Childhood Yes (n=135); Yes / No (n=84); No / Yes(n=215); No / No (n=146).

Post-traumatic stress disorder (PTSD) is a disorder where a person undergoes something intensely distressing, the memory of which stays with them, and they repeatedly relive it in a frightening manner.
People who had not gone through an adverse experience during their childhood, such as losing a parent, were found to have signiﬁcantly higher rate of PTSD in case of damage from the earthquake thanthose who had no such experience. Inoue et al. (2019) presented the results of such a study. In a 2013 survey of older adults in Iwanuma City, JAGES analyzed data from 580 people who answeredquestions about adverse experiences in their childhood, such as bereavement, abuse, and ﬁnancial distress; 9.7% of people were found to have PTSD after the earthquake. People whose houses weredamaged and those who lost relative/friend were also at high risk of PTSD. Damage to houses and the loss of loved ones due to disaster was linked to the onset of PTSD in those who had not faced adversity,whereas no such association was found for those who had undergone adversity.

There was 30% lower risk of developing depressive symptoms
after the disaster if persons had given or received social
support before the disaster.
We adjusted for age, sex, income, living alone, and the effects of house damage andlosing loved ones.
* indicates a statistically signiﬁcant association.

0.7*

Post-earthquake0

Odds ratio

Risk of Developing Depressive Symptoms

1

No experience of adversity

4

1

0.1
0

Post-earthquake

5

0.6

Prevalence Ratio (PR)Probability of having high depressive symptoms

0.8

Partial damage

Pre-earthquake

Post-traumatic stress disorder (PTSD) after the earthquake became more pronounced in those who did not experience
adverse childhood experiences

Optimists have fewer depressive and post-traumatic stress symptoms after a disasterNo damageIwanuma Project

Loss of loved
ones

Damageto house

Individual-levelsocial ties

Community-levelsocial ties

Hikichi H, Aida J, Tsuboya T, Kondo K, Kawachi I: Can community social cohesion prevent posttraumatic stressdisorder in the aftermath of a disaster? A natural experiment from the 2011 Tohoku Earthquake and tsunami. Am J
Epidemiol. 2016 May 15;183(10):902-10. doi:10.1093/aje/kwv335. Epub 2016 Mar 29.

Giving and receiving social support

Sasaki et al. (2019) examined whether pre-disaster social support functions as a disaster preparedness resource to mitigate post-disaster depressive symptoms among older survivors of the 2011 Great East
Japan Earthquake and Tsunami. Based on JAGES Iwanuma data from 2010 and 2013, 2,242 older adults who did not have depressive symptoms in the 2010 survey were analyzed. In the follow-up survey in2013, 16.2% of those surveyed developed depressive symptoms. Survivors who had all four types of social support (giving and receiving emotional and instrumental support) prior to the disaster
experienced a lower risk of developing depressive symptoms than those who did not have such support, even after adjusting for demographic and disaster-damage-related variables. This result
demonstrates that social support in daily life might help older adults maintain psychological health following disasters.

11

In the aftermath of a disaster, the risk of posttraumatic stress disorder (PTSD) is high. We sought to examine whether the predisaster level of community social cohesion was associated with a lower risk of
PTSD after the earthquake and tsunami in Tohoku, Japan, on March 11, 2011. The baseline for our natural experiment was established in a survey of older community-dwelling adults who lived 80
kilometers west of the epicenter 7 months before the earthquake and tsunami. A follow-up survey was conducted approximately 2.5 years after the disaster. We used a spatial Durbin model to examine theassociation of community-level social cohesion with the individual risk of PTSD. Among our analytic sample (n = 3,567), 11.4% of respondents reported severe PTSD symptoms. In the spatial Durbin model,
individual- and community-level social cohesion before the disaster were signiﬁcantly associated with lower risks of PTSD symptoms (odds ratio = 0.87, 95% conﬁdence interval: 0.77, 0.98 and odds ratio =0.75, 95% conﬁdence interval: 0.63, 0.90, respectively), even after adjustment for depression symptoms at baseline and experiences during the disaster (including loss of loved ones, housing damage, andinterruption of access to health care). Community-level social cohesion strengthens the resilience of community residents in the aftermath of a disaster.

12

Essaybridging and linking social capital – Qualitative study of
5 Bonding,public health nurses

Pre- and Post- Earthquake

Clarifying human connections among public health nurses, external organizations, and disaster survivor groups
Linking Social Capital (Connection with administration)• Connection with regional leaders • Livelihood support• Information gathering • Health counseling• Connections among external supporters• Mutual aid• Isolated people exchanging
information to rebuild their lives

Volunteer groups etc.

Pre- and Post- Earthquake

People facing ﬁnancial hardship after a disaster had up to 1.47 times higher risk of sleep disorders
Aggravating Factors

Public health nurse

Communities in shelters
and temporary housing

Bonding
Social capital(Connections within the local
community)

7 Predictors of sleep problems in disaster survivors

Iwanuma Project

Preventing sleep problems

Details of damage causedby the earthquake

Short sleep duration

FinancialhardshipPoor sleep quality

Aggravation of sleep disorders

Financial hardshipexacerbates sleep
problems

Sleep insufﬁciency
Insomnia symptoms

Li X, Buxton OM, Hikichi H, Haneuse S, Aida J,
Kondo K, Kawachi I: Predictors of persistent
sleep problems among older disaster survivors:a natural experiment from the 2011 Great East
Japan Earthquake and tsunami. Sleep. 2018 Jul
1;41(7): zsy084. doi:10.1093/sleep/zsy084.

Sleep medication use

Short sleep duration

Bridging Social Capital(Connections with external organizations)

Complete destructionof house• Isolated support• Event sponsorship• Emergency food distribution

Sleep insufﬁciency
Poor sleep quality
Insomnia symptoms
Sleep medication use

Complete or partial
destruction ofhouse causing use of
sleeping medication use

Hikichi H, Kondo K, Aida J, Kondo N: Social capital in disaster medicine Group interviews with public health nurses working in areas stricken by the Tohoku earthquake. Japanese Journal of Disaster Medicine 2015;20 (1):51-56.

In October 2013, Hikichi et al. (2015) conducted group interviews with 22 public health nurses in Miyagi prefecture involved in health care activities for disaster survivors. We obtained the following
suggestions about the effects of social capital in affected areas. Social capital before the earthquake facilitated mutual aid among evacuees. They were able to share emergency food and drinks, and launchedcommunity groups to exchange information. One municipality in Miyagi prefecture established a meeting hall to prevent solitary death by improving social connections among victims. In othermunicipalities, survivors relocated to disaster relief housing in communities to preserve their pre-disaster social networks. Although some survivors had few acquaintances in the temporary housing
complex, they could make connections by participating in social events. We also found that combinations of different types of social capital (bonding, bridging, and linking) could be more effective for thevictims’ health and livelihood. For example, public health nurses could support victims effectively by collecting information about their personalities and chronic diseases from neighbors. They would thus
be able to conduct health care activities in cooperation with victims (linking social capital), by using social networks among victims (bonding social capital).

Short sleep duration

Partial destructionof house

Sleep insufﬁciency
Poor sleep quality
Insomnia symptoms
Sleep medication use

Short sleep duration

Health caredisruption

Disruption ofaccess to healthcare predict poor
sleep quality

Sleep insufﬁciency
Poor sleep quality
Insomnia symptoms
Sleep medication use

6 Maintaining social ties through group relocation

Pre- and Post- Earthquake

Short sleep duration

Loss of close
relatives/friends

The relationship between methods of relocation and social ties

No signiﬁcantassociation withloss of close
relatives/friends

Sleep insufﬁciency
Poor sleep quality
Insomnia symptoms
Sleep medication use

Preventive Factors
0.06

Availability of social support
before the disaster0.053 (p=0.013)
0.04
Change in Social Ties Score

Instrumental
Support0.02
0.00

Aggravation of sleep disorders

Short sleep duration
Sleep insufﬁciency

Pre-disaster social
support associatedwith reduced risksof having
sleep problems

Poor sleep quality
Insomnia symptoms
Sleep medication use-0.039 (p=0.035)
n=79

Emotional
Supportn=96-0.06
Group relocation(1) The value (risk ratio) in the ﬁgure:-The greater the number is than one,and the more often sleep problems occur.
-The smaller the number is than one,lower the incidence of sleep problems.
(2) If the horizontal line does notintersect the vertical line with a risk ratioof one, the result is statistically signiﬁcant.

Short sleep duration

-0.02
-0.04

Hikichi H, Sawada Y, Tsuboya T, Aida J, Kondo K, Koyama S, Kawachi I: Residential relocation and change in social
capital: A natural experiment from the 2011 Great East Japan Earthquake and tsunami. Sci Adv. 2017 Jul 26;3(7):e1700426. doi:10.1126/sciadv.1700426

Individual relocation

Social connections in the community ( “social capital” ) represent an important source of resilience in the aftermath of major disasters. However, little is known about how residential relocation due tohousing destruction affects survivors’ social capital. We examined changes in social capital among survivors of the 2011 Great East Japan Earthquake and Tsunami. People who lost their homes were
resettled to new locations by two primary means: (i) group relocation to public temporary trailer housing or (ii) individual relocation, in which victims moved into government-provided housing by lottery or
arranged for their own accommodation (market rental housing or private purchase/new construction). The baseline for our natural experiment was established seven months before the 11 March, 2011
disaster, when we conducted a survey of older community-dwelling adults who lived 80-km west of the earthquake epicenter. Approximately 2.5 years after the disaster, the follow-up survey gathered
information about individual experiences of disaster as well as health status and social capital. Among 3421 people in our study, 79 people moved via group relocation to public temporary trailer housing,whereas 96 people moved on their own. The individual ﬁxed-effects model showed that group relocation was associated with improved informal socializing and social participation (B coefﬁcient = 0.053,
95% conﬁdence interval: 0.011 to 0.095). In contrast, individual relocation was associated with declining informal socializing and social participation (B coefﬁcient = −0.039, 95% conﬁdence interval: −0.074 to −0.003). Group relocation, as compared to individual relocation, appeared to preserve social participation and informal socializing in the community.
13

Preventing sleep problems

Sleep insufﬁciency
Poor sleep quality
Insomnia symptoms
Sleep medication use
0

0.5

1

1.5

2

Figure. Relationship between earthquake experience / presenceof social support before the disaster and sleep problems 3 years
after the disaster.
(Male n = 1,542 female n = 2,005)

Risk ratio
Sleep disorders are one of the most common health problems for people affected by natural disasters. Sleep disorders are reported to be associated with the development of chronic diseases such as Type 2
diabetes and cardiovascular disease, as well as psychiatric disorders. Li et al. (2018) analyzed data from the 2010 and 2013 JAGES surveys of older adults in Iwanuma City to ﬁnd ways to alleviate sleep
disturbances after the disaster. As of 2013, 41% of all respondents answered "experiencing insomnia symptoms," 27% answered they had "Poor sleep quality," and 22% reported "sleep medication use." Of
the damage caused by the earthquake, "ﬁnancial hardship," "damage to the house," and "health care disruption," were found to predict sleep problems. It was also found that instrumental support ("having
someone to look after you") before the disaster was more conducive to alleviating sleep problems than emotional support ("having someone listened to your concerns and complaints.") This is the ﬁrst study
to follow-up on the actual state of sleep problems over a long period after a disaster. For older adults, the study showed that, in addition to the usual support systems, post-disaster ﬁnancial support, house
repairs, and medical support may be helpful in maintaining long-term health.

14

Essayparticipation in exercise and hobby groups help to reduce depressive
8 Increased
symptoms in disaster survivors

Pre- and Post- Earthquake

Increased participation in exercise and hobby groups reduces depressive symptoms-0.001-0.0015-0.002*-0.002-0.0025-0.003-0.003*-0.0035-0.004-0.004
Change in frequencyof sports group
participation

Change in frequencyof hobby group
participation

Change in frequencyof volunteer group
participation

Direction and strength of association with changes in
depression pre- and post-earthquake (n = 3,567)

Change in frequencyof senior citizens'club participation* p <0.05, statistically signiﬁcantAdjusted for age and sex, educational attainment, impaired ADL,
change in drinking habits, change in smoking status, change injob status, dwelling house damage, death of family members,change in equivalent income, and change in IADL score.

p < 0.10 Statistically signiﬁcant trend

Depression alleviatedp <0.05 Statistically signiﬁcant

Depression aggravated-0.049Decrease in income

-0.06

0.025

Losing family member-0.034-0.04

Damage to house-0.02

Loss of employment /leave of absence

0

0.019

Pre- and Post- Earthquake

How to mitigate the deterioration of depressive
symptoms caused due to housing damage?
Frequency of participation in
exercise groups 5-6 times / month"or

Walking duration"75 minutes / day"

Housing damage "1 Stage*"* None / Partial damage /Half-destroyed /Major partial damage/Completely destroyed

-0.06
-0.08
-0.10

-0.12

-0.12

Hikichi H, Aida J, Matsuyama Y, Tsuboya T, Kondo K, Kawachi I: Community-level social
capital and cognitive decline after a natural disaster: A natural experiment from the 2011
Great East Japan Earthquake and tsunami. Soc Sci Med. 2018 Sep:111981. doi:
10.1016/j.socscimed.2018.09.057.

-0.14
Increased walking time per day

Community Social Ties

We examined prospectively whether community-level social capital can mitigate the adverse effects of natural disaster on cognitive decline in the aftermath of the 2011 Great East Japan Earthquake andTsunami. The baseline for our natural experimental study was established seven months before the disaster in a survey of older community-dwelling adults who lived in Iwanuma City, Japan, located 80 km
west of the epicenter. Two and a half years after the disaster, we conducted a follow-up survey of survivors to gather information about their individual experiences during the disaster (n = 3560; 82.1%
follow-up rate). Our primary outcome was the level of cognitive disability (measured on an 8-level scale) assessed within people's homes. Factor analysis established two subscales of community social
capital: a cognitive dimension (perceptions of community social cohesion) and a structural dimension (informal socializing and social participation). The prevalence of cognitive decline at follow-up (11.5%)
was three times higher than at baseline (4.2%). Our multiple membership multilevel model indicated that pre- versus post-disaster increases in community-level informal socializing and social participation
were associated with lower risk of cognitive decline (coefﬁcient = -0.12, 95% conﬁdence interval: -0.20 to -0.04). In addition, social capital mitigated the risk of cognitive decline due to housing damage(interaction effect coefﬁcient = -0.07, 95% conﬁdence interval: -0.14 to -0.01). Community-level informal socializing and social participation buffers the impact of housing damage on cognitive decline in
the aftermath of natural disaster. Relocating residents together with other community members may help to preserve community social capital and improve the cognitive resilience of older survivors.

11 Depressive symptoms and higher mortality on the day of the disaster

Mortality risk the day ofthe earthquake

For example, if a person with a "half-destroyed" house participates in an
exercise group ﬁve to six times a month or walks about 75 minutes aday, their depressive symptoms would be alleviated to the same level as
someone with "partial damage" to their house.

Mortality risk the day after
the earthquake> 2000m

1

11000 - 1999m

3.01(0.56, 16.16)

0.83(0.42, 1.65)

500 - 999m

16.88(4.33, 65.84)

0.76(0.38, 1.51)

0 - 499m

22.66(5.78, 88.84)

0.84(0.43, 1.68)

Living alone

11

3.04(0.47, 19.74)

1.05(0.54, 2.06)

Living with parent(s)6.67(0.83, 53.71)

0.45(0.10, 2.12)

Social interactions(Interacted with friends)

Not meeting any friends

1

1

Meeting some friends

2.06(0.51, 8.23)

0.46(0.26, 0.82)

Depressive symptoms

Normal1

1

Mild0.79(0.29, 2.19)

1.39(0.81, 2.38)

Moderate

1.14(0.29, 4.50)

1.45(0.62, 3.26)

Severe3.90(1.13, 13.47)

1.91(0.81, 4.50)

Independent

1

1Partially disabled

0.73(0.18, 2.89)

2.44(1.30, 4.56)

Disabled

0.32(0.04, 2.64)

2.97(1.43, 6.14)

Distance from coastline

HouseholdCo-habiting with others,
but not parent(s)(n=3,567)

Tsuji T, Sasaki Y, Matsuyama Y, Sato Y, Aida J, Kondo K, Kawachi I: Reducing depressive
symptoms after the Great East Japan Earthquake in older survivors through group exercise
participation and regular walking: a prospective observational study. BMJ Open. 2017 Mar
3;7(3): e013706. doi:10.1136/bmjopen-2016-013706.

After the disaster, support activities were conducted in many areas to encourage people to exercise and walk to improve the health of those affected by the disaster. However, it was unclear what effect these
activities would have. Therefore, Tsuji et al. (2017) analyzed data from JAGES' surveys of older people in Iwanuma City in 2010 and 2013. The study examined the relationship between the frequency ofparticipation in exercise groups and the time spent walking per day, with depressive symptoms. They found that post-earthquake participation in exercise groups increased by an average of 1.9 days per year
and walking time per day increased by 1.3 minutes compared to pre-earthquake. In both activities, the more the number increased, the more the depressive symptoms were alleviated. However, there was apositive relationship between the worsening of depressive symptoms and "loss of employment or leave of absence" and "damage to house." Based on the results, we estimated the amount of exercise andwalking required to alleviate the worsening of depressive symptoms associated with damage to the house. For example, if people whose houses were "half-destroyed" joined an exercise group ﬁve or six
times a month or walked 75 minutes a day, their depressive symptoms would be alleviated to the same level as those whose houses had “partial damage."

15

-0.04

-0.04

Pre- and Post- Earthquake

Mortality risk during disaster is four times higher for those with depressive symptoms.
Post-disaster mortality risk reduced by about half through interaction with friends.

0.075
Increased walking time

0.02

Increased frequency ofparticipation in exercise group

Standardized partial regression coefﬁcient(Statistical index showing the strength of relative relevance)

0.04

0.00
-0.02

Damage to house

Relationships with changes in depressive symptoms pre- and post-disaster

0.057

0.05

0.02

Factors considered for statistical impact

9 Physical activity helps to prevent depressive symptoms in older disaster survivors

0.06(n=3,560)

0.04

We examined prospectively the association between changes in participation in civic associations and changes in depressive symptoms among older survivors of the 2011 Great Eastern Japan Earthquake.
We analyzed questionnaire-based survey data on pre- and post-disaster participation in civic associations and depressive symptoms compiled for 3567 respondents aged 65 years and above. Changes inthese symptoms were assessed using a 15-item Geriatric Depression Scale (GDS) as a continuous variable for 2010 and 2013. We investigated four types of civic associations: sports, hobby, voluntary groups,
and senior citizens’ clubs. Changes in participation were calculated by subtracting the participation frequency measured in 2010 from that measured in 2013. Applying 95% conﬁdence intervals, we used
linear regression models with imputation to estimate the age- and sex-adjusted and multivariate-adjusted standardized coefﬁcients. The survivors' GDS scores increased by 0.13 points on average between
the pre-disaster and post-disaster periods. Average changes in the participation frequencies of respondents in each group were respectively +0.36 days/year, −5.63 days/year, +0.51 days/year, and −1.45
days/year. Increased frequencies of participation in the sports and hobby groups were inversely associated with changes in GDS scores (B = −0.003, Cohen's f2 = 0.10, P = 0.01 and B = −0.002, Cohen's f2= 0.08, P = 0.04, respectively). The associations did not differ depending on the experience of housing damage caused by the disaster. In contrast, we did not observe a signiﬁcant association betweenchanges in participation frequencies for voluntary groups or senior citizens' clubs and changes in GDS scores after multivariable adjustment. Depressive symptoms of older adults’ post-disaster may be
mitigated through increased frequency of participation in sports and hobby groups, though civic participation did not mitigate the adverse impact of disaster experiences on mental health.

0.08

0.06

Zhang W, Tsuji T, Yokoyama M, Ide K, Aida J, Kawachi I, Kondo K: Increased frequency ofparticipation in civic associations and reduced depressive symptoms: Prospective study ofolder Japanese survivors of the Great Eastern Japan Earthquake. Soc Sci Med. 2021 Mar 8;
276:11 3827. doi: 10.1016/j.socscimed.2021.113827.

-0.0045

Pre- and Post- Earthquake

Social ties mitigate the impact of disaster experiences on post-disaster cognitive disability

Cognitive Function

Partial regression coefﬁcient-0.001

Reduction of Geriatric Depression Scale (GDS) score

0-0.0005social capital mitigates progression of cognitive disability
10 Community-level
after a disaster

Iwanuma Project

Activities of daily living

The coastal area of Iwanuma City was hit by a massive tsunami
about an hour after the earthquake. Aida et al. (2017) summarized
the results of a study that found on the day of the disaster, the riskof death was about four times higher for older adults who had
severe depression symptoms before the earthquake than for those
who did not. They analyzed risks of mortality on the day of thedisaster and from the next day of the disaster to May 2014 using the
JAGES Iwanuma data of 860 older adults in the Tamaura area,
Iwanuma city, which was ﬂooded by the tsunami. On the day, 33
people died (mortality rate-3.8%). The mortality rate on the day ofthe disaster was as high as 12.8% for those who had severe
depressive symptoms before the disaster, and their adjusted risk ofdeath was about four times higher than for those who did not haveany depressive symptoms. The mortality risk may have increased
because the evacuation was delayed due to cognitive decline
associated with depression, or because people gave up, thinking
that evacuation would not save them. The mortality risk on the dayof the disaster tended to also be higher for those with rich social
interactions before the disaster. Among such people, actions such as
trying to help a friend may have delayed evacuation from thetsunami. Additionally, 95 people died the day after the earthquake
in May 2014. During this period, the risk of death for those with richsocial interactions was about half that of those who did not. The
results show the importance of helping people with severe
depressive symptoms to minimize tardiness in evacuation, andassisting those who are isolated after the disaster.

Note: Adjusted for age, sex, medical history, lifestyle, etc. Logistic regression analysis applied for mortality on the day. Analysis for the death fromthe next-day of the disaster, Cox proportional hazard model was applied.
Aida J, Hikichi H, Matsuyama Y, Sato Y, Tsuboya T, Tabuchi T, Koyama S, Subramanian SV, Kondo K, Osaka K, Kawachi I: Risk of mortality during and after the 2011 Great East Japan
Earthquake and tsunami among older coastal residents. Sci Rep. 2017 Nov 29;7(1):16591. doi:10.1038/s41598-017-16636-3.

16Essaysocial ties mitigate post-earthquake progression of
12 Individual-levelcognitive disability

Pre- and Post- Earthquake

14 Positive effects on mental health of group relocation into temporary housing
Figure 1 Relationship between relocation methods and social support* p <0.05, ** p <0.01, *** p <0.001

-0.05

-0.10

-0.10***

Hikichi H, Tsuboya T, Aida J, Matsuyama Y, Kondo K, Subramani an SV, Kawachi I: Social capital and cognitive decline
in the aftermath of a natural disaster: a natural experiment from the 2011 Great East Japan Earthquake and tsunami.
Lancet Planet Health. 2017 Jun;1(3): e105-e113. doi:10.1016/S2542-5196(17)30041-4.

-0.15
Improved social ties

Deteriorated social ties

In this natural experiment, the baseline for our study was established 7 months before the 2011 Great East Japan Earthquake and Tsunami in a survey of older community-dwelling adults who lived 80 km
west of the epicentre (59·0% response rate). About 2 and a half years after the disaster, which occurred on March 11, 2011, the follow-up survey collected information about personal experiences ofdisaster as well as incidence of cognitive disability. Our primary outcome was cognitive disability (measured on an 8-level scale) assessed by in-home assessment. We obtained 5058 respondents at thebaseline survey (59·0% response rate) and re-contacted 3594 survivors in the follow-up survey (82·1% follow-up rate). The experience of housing damage was associated with risk of cognitive impairment(coefﬁcient 0·05 [95% CI 0·03 to 0·07]). Factor analysis of our analytical sample (n=3566) established two subscales of social capital: a cognitive dimension (perceptions of community social cohesion) anda structural dimension (informal socialising and social participation). Fixed effects regression indicated that improved informal socialising and social participation mitigated the risk of cognitive
decline due to housing damage (coefﬁcient –0·10 [95% CI –0·14 to –0·05]) and deteriorating informal socialising and social participation aggravated the effect of housing damage on cognitive decline(coefﬁcient 0·04 [0·01 to 0·07]). Improved informal socialising and social participation reduces the risk of cognitive decline due to housing damage in the aftermath of natural disasters. Interventions topromote civic participation should be tried to promote cognitive resilience of older survivors.

Lottery allocation

30%
25%
20%
15%
10%
5%
0%
Receiving social support[if they have someone
who listened to their concerns
and complaints]
n=222

Providing social support[if they listened tosomeone else’s concerns
and complaints]
n=212

3

2.5
1.93

1.5
1

1

1

0.4
0.2

0

0
Receiving social support Providing social support(p = 0.05)(p = 0.21)[if they have someone who[if they listened tolistened to their concerns
someone else’s
and complaints]
concerns and complaints]
The lack of receiving social support increases the risk ofserious psychological distress.

Relocation Method(p=0.36)Thus, the present results suggest thatthe method of resettlement totemporary housing is an important
predictor of access to social support.

Koyama S, Aida J, Kawachi I, Kondo N, Subramanian SV, Ito K, Kobashi G, Masuno K, Kondo K, Osaka K: Social support improves mental health among the victims relocated to temporary housing following the Great East Japan Earthquake and tsunami. Tohoku J Exp Med. 2014 Nov;234(3):241-7. doi:10.1620/tjem.234.241.

The victims of the Great East Japan Earthquake and Tsunami have been forced to live in temporary housing, by two different methods of resettlement: group allocation that preserved pre-existing local social
ties and lottery allocation. Koyama et al. (2014) surveyed the effects of various factors, including the resettlement methods and social support, on mental health. Survivors who underwent group allocation totemporary housing (and were thus living in proximity to people who were their neighbors before the disaster) were signiﬁcantly more likely to report receiving social support than those who underwent lottery
allocation. Moreover, respondents who were receiving social support showed signiﬁcantly lower psychological distress, although the resettlement approach was not signiﬁcantly associated with distress.

15 Review article: Disaster resilience in older populations

In areas with high social participation, the negative health impact of housing damage was reduced

Increasing levels of symptoms of dementia depending on the severity of damage to housing

Change in functional capacity score after the earthquake

0.00

0.8

1.29

0.6

0.5

Relocation to temporary housing together with pre-disaster community
members was signiﬁcantly associated with higher social support.
(Receiving social support p = 0.003 Providing social support p=0.050)

1.4

1

2

1

Group allocation
Lottery allocation

1.2

2.5

13 Community social capital helps to preserve functional independence in older survivors Pre- and Post- Earthquake

Pre- and Post- Earthquake

Community social participation
Lowest tertile
Middle tertile
Highest tertile

-0.05
-0.10

MiyagiEpicenter

Adjusted for individual social capital

-0.15
-0.20

Tokyo

-0.25
-0.30
Gero K, Hikichi H, Aida J, Kondo K, Kawachi I: Associations between
community social capital and preservation of functional capacity in theaftermath of a major disaster. Am J Epidemiol. 2020 Nov 2;189(11):1369-1378. doi:10.1093/aje/kwaa085.

-0.35
-0.40
-0.45

No damagePartial damage

Half destroyed

Mostly destroyed

Destroyed

Severity of housing damage
The strength of social connections in the community ("social capital") is hypothesized to be a crucial ingredient in disaster resilience. Gero et al. (2020) examined whether community-level social capital iscorrelated with the ability to maintain functional capacity among older Iwanuma City residents 2.5 years after the 2011 Great East Japan Earthquake and Tsunami. Functional capacity was measured by theInstrumental Activities of Daily Living scale, evaluating the survivors’ ability to use public transportation, shop for daily necessities, prepare meals, pay bills, and manage deposits and withdrawals at a bankor post ofﬁce independently. Three subscales of community-level social capital were assessed: social cohesion, social participation, and reciprocity. The results show that community-level social participation
was associated with a lower risk of functional decline after disaster exposure. The average level of social participation in the community also mitigated the adverse impact of housing damage on functional
status, suggesting a buffering mechanism.

17

35%

Group allocation

Figure 2 Relationship between social support and serious
psychological distressYes
No
Odds of serious psychological distress

0.00

Association between change in social ties and change in cognitive
disability due to housing damage

Percentage of people without social support

Impact of housing damage on cognitive impairment

0.04*

Pre- and Post- Earthquake

Survivors who underwent group allocation to temporary housing were signiﬁcantly more likely to report receivingsocial support than those who underwent lottery allocation

Social ties mitigate the progression of dementia due to a disaster

0.05

Iwanuma Project

Densely Inhabited Area
(DID) Flooded Area

Kawachi I, Aida J, Hikichi H, Kondo K: Disaster resilience in aging
populations: lessons from the 2011 Great East Japan Earthquake
and tsunami. Journal of the Royal Society of New Zealand. 2020
Feb 4;50(2):263-278. doi:10.1080/03036758.2020.1722186.

Recovery after major disaster poses a unique set of challenges for the older population, including disruption of medical care for pre-existing conditions, functional limitations that impede recovery, andsocial isolation following involuntary resettlement. In this review, we summarize the lessons about disaster resilience that have been learned (so far) from a unique ongoing ﬁeld study based in a communitythat was affected by the 2011 earthquake and tsunami in Japan. In the Iwanuma Study, baseline information about the health status and living conditions of older residents was collected seven months
before the disaster. A follow-up survey was conducted 2.5 years after the disaster, allowing us investigate the risk and protective factors for a range of disaster-related health sequelae, including mental
illness and cognitive disability. A consistent ﬁnding to emerge from our studies is the critical role of social connections (the "social capital" of a community) in protecting against the deleterious after-effectsof psychological trauma and involuntary resettlement following the disaster. In contrast to the emphasis on investing in material infrastructure to prepare for disasters, a review of our studies suggests that
repairing (or at least preserving) the social fabric of people's lives is a crucial ingredient in disaster resilience.

18

Essay16 Socializing with neighbors post-earthquake reduces depressive symptoms

Pre- and Post- Earthquake

Relationship between changes in neighborhood relationships and the degree of severity of depressive symptoms

0.15

0.1

No ➡ Yes(n=257)0
Yes ➡ No
(n=336)Neighborhood relationships
Yes ➡ Yes (Standard )(n=2,195)

-0.1
-0.2

Note: adjusted for changes in age, gender, medical treatment, living
alone, social participation, smoking habits, drinking habits, subjective
economic status, and walking habits before and after the earthquake, as
well as for the effects of relocation and losing loved ones.
* Indicates that there was a statistically signiﬁcant association.

0.01
No ➡ No(n=323)-0.3-0.4-0.39*

Sasaki Y, Tsuji T, Koyama S, Tani Y, Saito T, Kondo K, Kawachi I, Aida J: Neighborhood ties reduced
depressive symptoms in older disaster survivors: Iwanuma study, a natural experiment. Int J Environ
Res Public Health. 2020 Jan 3;17(1):337. doi:10.3390/ijerph17010337.

-0.5

Changes in neighborhood relationships before and after the earthquake
A study by Sasaki et al. (2020) found that older adults who increased neighborhood ties after the disaster were less likely to suffer from depressive symptoms. An analysis of data from a survey of 3,111 older
adults in Iwanuma in 2010 and 2013 showed that those who increased neighborhood ties after the earthquake, had 0.39 points less likely to worsen depressive symptoms after the earthquake than those
who had neighborhood ties before and after the earthquake. Increased neighborhood ties may have played a beneﬁcial role in the mental health of the older survivors affected by natural disasters.

17 Relocation affects social relationships in areas receiving displaced survivors

Pre- and Post- Earthquake

1

0.95
0.89

0.90

0.92

0.85

0.92 0.93
0.80 0.81

0.80

St(n= rong
40 er
0)
Mu
ch
str
o
(n= nge34 r)

W(n= eake
58 r
)

Mu
ch
w
(n= eake12 r)(re Nof; n ch=2 an,70 ge
6)

0.75

1.10
1.05
1.00

1.07
1

1

0.97

0.95
0.89

0.90
0.85

0.96 0.95

0.90
0.84

0.80

Gero K, Aida J, Kondo K, Kawachi I: Evaluation of trust within a community after survivor relocation following the Great East Japan Earthquake and tsunami. JAMA Netw Open. 2020 Nov;3(11):e2021166. doi:10.1001/jamanetworkopen.2020.21166.

IDPs Within 100 m
IDPs Within 250 m

Trust is a core component of social cohesion, facilitating cooperation and collective action in the face of adversity and enabling survivors to remain resilient. Residential stability is an important prerequisiteof developing trusting relations among community members. However, little is known about whether the movement of internally displaced persons (IDPs) after a disaster might change community
relations. Gero et al. (2020) explored perceived changes in trust after the 2011 Great East Japan Earthquake and Tsunami among 3250 nonrelocated residents of Iwanuma City. The results show that eachstandard deviation increase in the inﬂux of internally displaced persons (1 SD = 11 IDPs) within 250 m of a resident's home address was associated with higher odds of a decrease in the resident's
particularized (trusting people from the same community) and generalized trust (trusting people from other communities). Therefore, to avoid the erosion of social cohesion after a disaster, it may be crucial
to provide opportunities for social interaction between old and new residents of communities.
19

12.4

10

7.9

7.4

5

* N = 2,332 (the graph included only those without missing
information)* Tooth loss: Fewer numbers of teeth in responses from 2013 than2010
* Subjective economic deterioration and housing damage due to thedisaster were signiﬁcantly associated with tooth loss after adjusting forsex, age, education, income, pre-disaster health status, post-disastermental stress, and loss of loved ones.

Matsuyama Y, Aida J, Tsuboya T, Hikichi H, Kondo K, Kawachi I, Osaka K: Are lowered socioeconomic
circumstances causally related to tooth loss? A natural experiment Involving the 2011 Great East
Japan Earthquake. Am J Epidemiol. 2017 Jul 1;186(1):54-62. doi:10.1093/aje/kwx059.

0
No change

Became worse

No damage

Change in subjective economic circumstancesby the earthquake

Destroyed

Housing damage

A study by Matsuyama et al. (2017) found older people who were severely affected by the earthquake were more likely to lose their teeth. Housing damage and worsening economic conditions due to thedisaster were the risk factors. The study analyzed pre- and post-disaster data (2010 and 2013, N = 3,039) and showed that 8.2% of the study participants lost their teeth after the disaster. Subjective
economic deterioration and housing damage due to the disaster were associated with tooth loss. After statistically adjusting for sex, age, education, income, pre-disaster health status, post-disaster mental
stress, and loss of loved ones, subjective economic deterioration and housing damage due to the disaster were signiﬁcantly associated with 8.1% and 1.7% increases in the probability of tooth loss,
respectively. Disaster survivors were more likely to have poor oral health. Measures to support oral hygiene, such as distributing toothbrushes and having space for brushing teeth in evacuation centers,
are required.

19 Decreased social capital does not explain post-disaster increased depressive symptoms Pre- and Post- Earthquake

B: Association between changes in social support/social capital before and after the earthquakeand depression in 2013

Losing relatives

Emotional support fromfamily and friends

Losing friends

Instrumental support fromfamily and friends

Income change(Unit: 1 million yen)

Emotional support fromnon-family and friends

Deterioration of subjective
economic conditions

Instrumental support fromnon-family and friends

Loss of employment

Social participation

0.75
St(n= rong
55 er
3)
Mu
ch
str
o
(n= nge
36 r
)

1

15.5

A: Association between disaster-related experiences and depression in 2013

W
(n= eake
61 r
)

1.00

1.07

15

1.15

1.15

Mu
ch
w
(n= eake
12 r
)

1.10

1.20

(re Nof; n ch=2 an,55 ge
4)

1.15

1.15
1.05

Trust in people from your area
Multivariable-adjusted odds ratios

Multivariable-adjusted odds ratios

1.20

20

Decrease in social support and social capital after the disaster does not explain the increase in depressive symptoms
among disaster survivors

Changes in community relations (trust) among nonrelocated Iwanuma City residents
Trust in people from other areas

Pre- and Post- Earthquake

People severely affected by the earthquake were more likely to lose their teeth

Percentage of people who lost their teeth (%)

Degree of worsening depression symptoms (points)

0.2

18 Worsening ﬁnancial status increases risk of tooth loss after disaster

Iwanuma Project

Loss of house

Social connections
0.0

0.5

1.0

1.5

2.0

Changes in Depressive Symptoms (GDS Scores) 2010-2013
Note: Adjusted for the effects of municipality of residence, age, gender, education,
income, IADL, and marital status in 2010.

-0.5

0.0

-0.5

1.0

1.5

2.0

2.5

Changes in Depressive Symptoms (GDS Scores) 2010-2013
Shiba K, Yazawa A, Kino S, Kondo K, Aida J, Kawachi I: Depressive symptoms in the aftermath of major disaster: Empirical test of the social support
deterioration model using natural experiment. Wellbeing, Space and Society. 2020 Jan 1; 1:100006. doi: 10.1016/j.wss.2020.100006.

Depressive symptoms are known to increase among survivors who have experienced trauma after a major disaster. Post-disaster decrease in social capital has been claimed to be one potential cause.
However, Shiba et al. (2020) used follow-up data from approximately 3,500 survivors of the 2011 Great East Japan Earthquake and tsunami to investigate whether post-disaster changes in social capital
mediates the association between disaster traumas and increased depressive symptoms using statistically rigorous methods. They found that social capital did not explain the trauma- depression
associations.

20Essay20 Predictors of worsened depressive symptoms after disasterPost-earthquake3

20House Entirely
destroyed

House Entirely
destroyed (Men)House Entirely
destroyed (Women)

Have lost jobs

Disruption of accessto psychiatry

Tsuboya T, Aida J, Hikichi H, Subramanian SV, Kondo K, Osaka K, Kawachi I:
Predictors of depressive symptoms following the Great East Japan
Earthquake: A prospective study. Soc Sci Med. 2016 Jul; 161:47-54. doi:
10.1016/j.socscimed.2016.05.026. Epub 2016 May 20.

A unique feature of our study was the availability of information about mental health status pre-dating the disaster. Our sample comprised community-dwelling survivors aged 65 and older, who responded
to surveys in 2010 (i.e. one year before the disaster) and in 2013 (n = 3464). We categorized disaster exposure according to three types of experiences: loss of family/friends, property damage, anddisruption in access to medical service. Our main outcome was change in depressive symptoms, measured by the 15-item geriatric depression scale (GDS). Among the participants, 917 (26.5%) reported
losing a family member to the disaster, while a further 537 (15.5%) reported losing a friend. More than half of the participants reported some damage to their homes. After adjusting for demographics andbaseline mental health, people whose homes were completely destroyed had signiﬁcantly elevated depressive symptom scores three years later (+1.22 points, 95%CI: 0.80, 1.64, p < 0.0001). Disruptionof psychiatric care was also associated with change in GDS scores (+2.51 points, 95%CI: 1.28, 3.74, p < 0.0001). By contrast, loss of family/friends was no longer associated with GDS after 3 years; +0.18
points (95%CI: -0.018, 0.37, p = 0.08) for loss of family, and -0.045 points (95%CI: -0.28, 0.19, p = 0.71) for loss of friends. Three years after the disaster, survivors of the 2011 earthquake and tsunami
appeared to have recovered from the loss of loved ones. By contrast, property loss and disruption of psychiatry care were associated with persistent adverse impact on mental health.

21 Access to medical care is key to preserving functional independence

Post-earthquake

Relationship between disaster experiences and decline in functional independence
Change in instrumental activities of daily living (IADL) scoresHouse Entirely
destroyed

-0.2
-0.4

Have lost jobs

Disruption of accessto medical service(Internal Medicine)

On yearincrement of age

Ten years
increment of age

The value on the Y-axis is the decline in the level of independence score of older
adults (13-item version of Instrumental Activities of Daily Living, IADL).
House damage (entirely destroyed), loss of job, and disruption of access to medical
service were associated with signiﬁcant adverse impact on decline in physical andcognitive functions.

-1

Tsuboya T, Aida J, Hikichi H, Subramanian SV, Kondo K, Osaka K, Kawachi I: Predictors of decline in IADL functioning
among older survivors following the Great East Japan Earthquake: A prospective study. Soc Sci Med. 2017
Mar;176:34-41. doi: 10.1016/j.socscimed.2017.01.022. Epub 2017 Jan 18.

-1.2
We described associations between the type of disaster experience and change in instrumental activities of daily living among older adult survivors before and after a terrible disaster. The study took
advantage of a “natural experiment” afforded by the Japan Gerontological Evaluation Study (JAGES), a nationwide cohort study established in 2010, seven months prior to the earthquake and tsunami. A
follow-up survey was conducted in 2013. This study was conducted in Iwanuma, which was directly struck by a tsunami. Our sample comprised community-dwelling aged survivors in Iwanuma who
responded to questions about personal circumstances and functional status both before and after the disaster (N = 3547). Individual experiences of earthquake and tsunami damage were used as an
exposure variable. The outcome was changes in self-reported 13-item instrumental activities of daily living (IADL), which was assessed both before and after the disaster. Among the participants, 931
reported losing family member(s) to the disaster, while a further 549 reported losing friend(s). More than half of the participants reported damage to their houses while approximately 1 in 8 lost their car(s).
The multivariable OLS regression revealed that complete house loss and disruption of internal medicine were associated with signiﬁcantly worse IADL: −0.67 points (95%CI: −0.99, −0.34) for entirely
destroyed homes; −0.40 points (95% CI: −0.71, −0.092) for disruption of internal medicine. By contrast, loss of family/friends/pets/cars and disruption to the other medical service were not associated withdecline in IADL. Complete house loss and disruption of access to internal medicine after a disaster were associated with signiﬁcant adverse impacts on declines in physical and cognitive functions 2.5 years
after the disaster, while loss of family/friends was not.
21

1.46

1.44

1.44
1.43
Hikichi H, Aida J, Kondo K, Tsuboya T, Kawachi I: Residential relocation and obesity after a natural disaster:A natural experiment from the 2011 Japan Earthquake and tsunami. Sci Rep. 2019 Jan;9(1):374.
doi:10.1038/s41598-018-36906-y.

1.40
0

Bar

Fast food outlet

Supermarket

Natural disasters are often associated with forced residential relocation; thereby, affected people experience a change in food environment that results in an increased body mass index. However, there aresome studies that have examined whether a change in food environment causes risks of obesity after a natural disaster. To address this question, we leveraged a natural experiment of residential relocationin the aftermath of the 2011 Japan Earthquake and Tsunami. Our baseline data came from a nationwide cohort study of older community-dwelling adults conducted 7 months prior to the disaster. By
chance, one of the ﬁeld sites (Iwanuma City, Miyagi Prefecture) was directly in the line of the tsunami. Approximately 2.5 years after the disaster, we ascertained the residential addresses and health statusesof 3,594 survivors aged 65 years or older (82.1% follow-up rate). Fixed effects multinomial logistic regression showed that shortened distances to food outlets/bars increased the risks of transitioning from
BMI in the normal range (18.5–22.9) to obesity (≥25.0) (Odds ratios: 1.46 for supermarkets; 1.43 for bars; 1.44 times for fast food outlets). Radically changed food access after a natural disaster may raise
the risk of obesity among older survivors.

23 Long-term effects of total destruction of one’ s house on cardiometabolic risks

Post-earthquake

Degree of property damage and changes in cardiometabolic proﬁles before and after the earthquake (2010–2013)
Waist circumference (cm)No Damage to house

No Damage to house

Partial damage

Partial damage

Half damage

Half damage

Major damage

Major damage

Complete destruction

Complete destruction
-0.5

0.0

0.5

1.0

-2.5

HDL cholesterol (mg/dL)

-0.6
-0.8

1.46

BMI (kg/m2)(n=3,547)

Post-earthquake

Note: Odds ratios mean the risks of being obese signiﬁcantly associatedwith each 1 km shortening of the distance to the nearest foodestablishment

1.42

1

0

1.48

Odds ratio

Change in Geriatric Depression Scale (GDS)* Values on the Y-axis show the reduced scores on
the depressive symptom scale for older adults(15-item version of the geriatric depression scale)* Total destruction of house, loss of work, andbarriers to psychiatric consultation (failure to see a
psychiatrist) had a statistically signiﬁcant impact on
the worsening of depression three years after thedisaster.

22 Residential relocation linked to increased obesity due to changed food environment

Iwanuma Project

0.0

2.5

7.5

5.0

LDL cholesterol (mg/dL)

No Damage to house

No Damage to house

Partial damage

Partial damage

Half damage

Half damage

Major damage

Major damage

Complete destruction

Complete destruction
-7.5

-5.0

-2.5

0.0

n=1,195. Estimates of changes in values before and after the earthquake are indicated by •.
If the lines around it do not cross 0, it indicates that the difference was statistically signiﬁcant.

2.5

-10

0

10

Shiba K, Hikichi H, Aida J, Kondo K, Kawachi I: Long-term associations between disaster experiences and cardiometabolic risk: A natural experiment from the 2011
Great East Japan Earthquake and tsunami. Am J Epidemiol. 2019 Jun 1;188(6):1109-1119. doi:10.1093/aje/kwz065.

Older adults, whose homes were completely destroyed by the disaster (versus no property damage), had worse cardiometabolic proﬁles two and a half years after the disaster. Shiba et al. (2019) conducted
such a study that revealed the long-term health effects of a natural disaster. They combined data from 2010 and 2013, from the survey of older adults in Iwanuma by JAGES, with data from health check-ups
carried out by the city, and analyzed data from 1,195 individuals. People whose homes were destroyed had a higher body mass index (BMI) by 0.81,kg/m2 and waist circumference by 4.26 cm than those
whose homes were not damaged, and their HDL cholesterol was 4.77 mg/dl lower. There was no association between losing a family/friend or minor property damage and cardiometabolic proﬁles, whichsuggests the long-term associations between home loss and the outcomes may be due to circumstances speciﬁc to those whose homes were completely destroyed, such as relocation to temporary housing.
22Essay24 Relocation to prefabricated housing doubled the risk of depression

Post-earthquake

Odds ratios of depression according to type of post-disaster housing

1.49

1.40

1.00
0.80

0.00
Prefabricatedhousing(n=42)

Existing private
housing(n=19)

Newly establishedhousing(n=36)

25 Post-disaster mental health as a predictor of mortality

Post-earthquake

0.29**

0.25
0.20
0.15
0.12*

0.10
0.05
0.00

Other
(n=10)

Many people were forced to relocate because they lost their homes due to the earthquake. No previous research has analyzed relocation and psychological problems of survivors using pre- and post-disasterdata. The JAGES analyzed data from a survey of 3,567 older adults in Iwanuma City, conducted in 2010 (before the earthquake) and in 2013 (after the earthquake). The study examined the association
between relocation and the risk of developing depressive symptoms after the disaster. The results showed no difference in the risk of developing depressive symptoms between those who did not relocate
and those who relocated to existing private housing or newly established housing. However, the risk of developing depressive symptoms after the disaster doubled for those who moved to prefabricatedhousing. It suggests that older adults moving to prefabricated housing may lead to the risk of developing depressive symptoms.

* p < 0.05** p < 0.01 indicates statistical signiﬁcance

0.30

Sasaki Y, Aida J, Tsuji T, Miyaguni Y, Tani Y, Koyama S, Matsuyama Y,
Sato Y, Tsuboya T, Nagamine Y, Kameda Y, Saito T, Kakimoto K, Kondo
K, Kawachi I: Does type of residential housing matter for depressive
symptoms in the aftermath of a disaster? Insights from the Great East
Japan Earthquake and tsunami. Am J Epidemiol. 2018 Mar;187(3):455-464. doi:10.1093/aje/kwx274.

0.50

No relocation(n=2,084)

0.35

Regression coefﬁcient

Risk of developing depression

1.00

Note: Adjusted for the impact of age, gender,
subjective health, educational history, income,living alone, losing close loved ones due to theearthquake, and damage to the house.
※* Indicates that there was a statisticallysigniﬁcant association.
* The analysis included 2,242 people who did nothave depressive symptoms at the time of the 2010
survey.

2.07*

1.50

Post-earthquake

Association between severity of housing damage and increased cognitive disability score

2.50

2.00

26 Housing damage is associated with increased cognitive disability

Iwanuma Project

0.07

0.05
Partial damage(n=1,496)

Half damage(n=257)

Major damage(n=131)

Hikichi H, Aida J, Kondo K, Tsuboya T, Matsuyama Y, Subramani an SV, Kawachi
I: Increased risk of dementia in the aftermath of the 2011 Great East Japan
Earthquake and tsunami. Proc Natl Acad Sci USA. 2016 Nov 8;113(45):E6911-E6918. doi:10.1073/pnas.1607793113. Epub 2016 Oct 24.

Complete destruction(n=158)

No previous study has been able to examine the association by taking account of risk factors for dementia before and after the disaster. We prospectively examined whether experiences of a disaster wereassociated with cognitive decline in the aftermath of the 2011 Great East Japan Earthquake and Tsunami. The baseline for our natural experiment was established in a survey of older community-dwelling
adults who lived 80 km west of the epicenter 7 months before the earthquake and tsunami. Approximately 2.5 years after the disaster, the follow-up survey gathered information about personal experiencesof disaster as well as incidence of dementia from 3,594 survivors (82.1% follow-up rate). Our primary outcome was dementia diagnosis ascertained by in-home assessment during the follow-up period.
Among our analytic sample (n = 3,566), 38.0% reported losing relatives or friends in the disaster, and 58.9% reported property damage. Fixed-effects regression indicated that major housing damage andhome destroyed were associated with cognitive decline: regression coefﬁcient for levels of dementia symptoms = 0.12, 95% conﬁdence interval (CI): 0.01 to 0.23 and coefﬁcient = 0.29, 95% CI: 0.17 to
0.40, respectively. The effect size of destroyed home is comparable to the impact of incident stroke (coefﬁcient = 0.24, 95% CI: 0.11 to 0.36). The association between housing damage and cognitive decline
remained statistically signiﬁcant in the instrumental variable analysis. Housing damage is an important risk factor for cognitive decline among older survivors in natural disasters.

27 Increased risk of developing arthritis associated with disaster trauma

Post-earthquake

Post-disaster depressive symptoms, post-traumatic stress disorder (PTSD), and mortality rates* The ﬁgure shows the hazard ratios for mortality amongpeople who had depression alone, depression and PTSD
together, and PTSD alone (relative to people who have neither
depression nor PTSD).

2.5
Hazard ratio for mortality

2
1.5
1
0.5
0
Depression(n=974)

Depression and PTSD

PTSD
(n=747)

Li X, Aida J, Hikichi H, Kondo K, Kawachi I: Association of postdisaster depression
and posttraumatic stress disorder with mortality among older disaster survivors ofthe 2011 Great East Japan Earthquake and tsunami. JAMA Network Open. 2019;2(12): e1917550. doi:10.1001/jamanetworkopen.2019.17550.

To assess whether postdisaster depression and PTSD were associated with mortality in older disaster survivors, this cohort study was conducted. Prospective data were retrieved from older Japanese adults in
Iwanuma City, Miyagi Prefecture, which was directly affected by the 2011 Great East Japan Earthquake and Tsunami. Mortality data were obtained by linkage to the national long-term care insurance
database. Cox proportional hazards regression models were adjusted for predisaster sociodemographic characteristics, health behaviors, social cohesion, predisaster depression, and disaster experiences. In
adjusted models, depression was associated with more than double the risk of mortality (hazard ratio, 2.29; 95% CI, 1.54-3.42); PTSD was not associated with increased risk of mortality (hazard ratio, 1.10;
95% CI, 0.73-1.64). When evaluating the association of the 4-category comorbid depression and PTSD variable with mortality, survivors with depression only (HR, 2.24; 95% CI, 1.43-3.49), as well as thosewith comorbid depression and PTSD (HR, 2.54; 95% CI, 1.50-4.27), were at increased risk of death during the follow-up period compared with those with neither depression nor PTSD. Depression, but not
PTSD, was associated with mortality during 3.3 years of follow-up among older disaster survivors. These ﬁndings suggest that long-term mental health consequences of natural disasters may exist and thattreating depression in older survivors of disasters may be beneﬁcial.

23

Percentage of people who develop arthritis (%)

3

7
6

Those who were affected by the earthquake had ahigher incidence of arthritis after the disaster(n=2,360)

6.3

5
4.8

4
3

3.4

3.0

2
1
0
No change

Deteriorated

Changes in economic conditions
due to the earthquake

No damage

DamageIkeda T, Aida J, Kawachi I, Kondo K, Osaka K: Causal effect of deteriorating socioeconomic
circumstances on new-onset arthritis and the moderating role of access to medical care: A
natural experiment from the 2011 Great East Japan Earthquake and tsunami. Soc Sci Med.
2020 Nov;26 4:113385. doi: 10.1016/j.socscimed.2020.113385. Epub 2020 Sep 25.

Damage to house

The results show the importance of identifying and treating people with arthritis in the initial stages after a disaster. It has been reported that the health effects of the disaster are long-term andwide-ranging. However, no study has ever examined whether it affects the onset of arthritis. We analyzed follow-up data from 2,360 older adults aged 65 and over before (2010) and after (2013) theearthquake to examine the impact of the disaster and the onset of arthritis. Results showed a 16% increase in the risk of developing arthritis in the group with worse economic conditions compared to thegroup with no change in economic conditions. Similarly, the risk of arthritis onset was 8% higher in the group that experienced total destruction of the home compared to those with no housing damage.
Injuries caused by the earthquake were not only external but also extended to the tissue within the joints. These types of injuries in the joints immediately after such an earthquake are thought to result inthe onset of chronic arthritis. Therefore, in addition to assessing external injuries, checking for injuries that cannot be easily visually conﬁrmed, such as joint tissue injury, in evacuation shelters immediately
after the earthquake, is thought to be important for early detection and treatment.

24

Essay28 Risk of increased BMI due to relocation to temporary housing

Post-earthquake

Empirical evidence on the relationship between property damage/relocation to temporary housing and increased BMI
BMI ( kg/m2)

30 Long-term trends in mental health after disaster

PTSS (n=253)

2013

2016

PTSS (n=106)

No PTSS (n=147)

PTSS (n=109)

No PTSS (n=1,913)

Transition of PTSS

Persistent symptoms (n = 106) 4.7%

Recovery (n = 147) 6.5%

Delayed onset (n = 109) 4.8%

No onset (n = 1,913) 84.1%

Total effects

0.47(72.6%)

1.47(15.1%)

Effects explainedby moving totemporary housing

Depression (n=504)

2010
0.00

0.25

0.50

0.75

No PTSS (n=2,022)

9.73(100%)

Total effects

Effects explainedby moving totemporary housing

Long-term Impact

Trajectories of post-traumatic stress symptoms and depression, 2.5 and 5.5 years after the disaster

LDL cholesterol (mg/dL)

0.65(100%)

Iwanuma Project

1.00

0

Changes from 2010 to 2013

No Depression (n=1,231)

10

Changes from 2010 to 20132013

Depression (n=338)

No Depression (n=166)

Depression (n=168)

No Depression (n=1,063)

Shiba K, Aida J, Kondo K, Nakagomi A, Arcaya M, James P, Kawachi I: Mediation of the relationship between home loss and worsened cardiometabolic proﬁles of older disaster survivors by post-disaster relocation: A natural experiment from the Great East Japan Earthquake and tsunami.
Health & Place. 2020 Nov 1; 66:102456. doi: 10.1016/j.healthplace.2020.102456.

After the Great East Japan Earthquake in 2011, there was an increased risk of metabolic syndrome in people who experienced property damage; however, the underlying mechanism was unclear. Shiba etal. (2020) analyzed pre- and post-disaster (2010 and 2013) data from approximately 1,165 older survivors aged 65 years and over affected by the Great East Japan Earthquake and demonstrated that 72.6%of the effect on worsening BMI was mediated by property damage and relocation to temporary housing. Potential explanations include changes in the neighborhood environment, such as the proximity torestaurants or the difﬁculty of cooking in the new living environment; however, further research is needed to determine if there is a link between moving to temporary housing and increased BMI.

2016

Depression (n=258)

Transition ofdepressive symptoms

No Depression (n=80)

Persistent symptoms (n = 404) 23.3%

Depression (n=63)

No Depression (n=103)

Recovery (n = 268) 15.4%

Depression (n=83)

No Depression (n=85)

Depression (n=101)

Delayed onset (n = 101) 5.8%

No Depression (n=962)

No onset (n = 962) 55.4%

Kino S, Aida J, Kondo K, Kawachi I: Long-term trends in mental health disorders after the 2011 Great East
Japan Earthquake and tsunami. JAMA Netw Open. 2020 Aug 3;3(8): e2013437.
doi:10.1001/jamanetworkopen.2020.13437.

29 Persistent impact of housing loss on cognitive disability 6 years after disasterLong-term Impact

Individual symptoms of mental illness changed pre- and post-earthquake; however, prevalence in community did not

Persistent impact of housing loss on cognitive disability 6 years after disaster

0.14
0.12

Rate of Prevalence

Regression Coefﬁcient

0.08
0.07
0.06
0.04
0.02
0.00

Hikichi H, Aida J, Kondo K, Kawachi I: Persistent impact of housing
loss on cognitive decline after the 2011 Great East Japan
Earthquake and tsunami: Evidence from a 6-year longitudinal
study. Alzheimers Dement. 2019 Aug;15(8):1009-1018. doi:
10.1016/j.jalz.2019.04.016. Epub 2019 Aug 1.

0.01
Affected

Minor

Major

Destroyed

Depression

We previously established that housing loss and residential dislocation in the 2011 Japan earthquake and tsunami was a risk factor for cognitive decline among older survivors. The present study extends
the follow-up of survivors to six years. The baseline for our natural experiment was established in a survey of older community-dwelling adults who lived 80 km west of the epicenter seven months before
the earthquake and tsunami. Two follow-up surveys were conducted approximately 2.5 and 5.5 years after the disaster to ascertain the housing status and cognitive decline from 2810 older individuals(follow-up rate through three surveys: 68.4%). The experience of housing loss was persistently associated with cognitive disability (coefﬁcient = 0.14, 95% conﬁdence interval: 0.04 to 0.23). Experiences of
housing loss continued to be signiﬁcantly associated with cognitive disability even six years after the disaster.

25

30

Depressive symptoms

25

0.10*

0.06

35

(n=2,810)* p <0.01 statistically signiﬁcant association withcognitive decline

0.12*

0.10

Severe emotional trauma, such as the loss of a relative or damage to one's home in a disaster, can lead to post-traumatic stress symptoms (PTSS), such as sudden ﬂashes of painful memories, anddepression. Kino et al. (2020) analyzed the results of the JAGES surveys of older adults in Iwanuma City in 2010, 2013, and 2016 to examine the long-term effects of the disaster on mental health; 13.6% of
people who had no depressive symptoms before the disaster had depressive symptoms in 2013. By 2016, 50% of them had recovered. In contrast, the number of people with PTSS was 11% of the total as of2013. As of 2016, 60% had recovered, while 40% still had PTSS.

PTSS

20
15
10
5
0
2010

2013

2016

Post-traumatic stress symptoms (PTSS) and depression are common among survivors of major disasters. However, few studies have followed participants over an extended period to identify the symptoms ofmental illness or to document the prevalence of mental illness symptoms in the community. In a study of 2,781 older adult survivors in Iwanuma City, about half of older adults who reported PTSS anddepression had recovered 5.5 years after the disaster, while about half were still reporting symptoms more than ﬁve years later. However, for the region as a whole, the prevalence of depression was foundconstant between pre- and post-disaster data. This suggests that the region itself has the "capacity to be ﬂexible and resilient in the face of adversity and difﬁculty."

26

Essay31 Relocation linked with increased cardiometabolic risksLong-term Impact

-50

-25

0

25

50

-10

-5

0

5

-20

0

20

ec
ed

ici
n

Jo
b

lm

no
co

er

na

ee

in
in
t

tiv

pt

in
s

ion

ub

jec

in
g
us

are

los
s

us
m

De

ic
s

str
oy

tat

ed

r
e:
da

in
g

m

da

ag

m

ag

ag

e:

e:

M

M

in
o

ajo

r

ted

ru
ter
In

NonDisplacedDr
op

Both genders
Male
FemaleHo

Displacedus

Low (Reference Value)
Medium
High

0.0

Ho

Whole

DelayedNever in 2013 or 2016

Kino et al. (2021) explored a lingering inﬂuence of persistence ordelayed onsets of mental health problems after 5.5 years. They
found that job loss was associated with persistent post-traumaticstress symptoms (PTSS) while a drop in subjective economic status
predicted delayed onset of PTSS. In addition, depressive symptoms
pre-dating the disaster was a strong predictor of persistent anddelayed onset PTSS.
Worsening economic situation due to the disaster rather than theuncontrollable disaster experience itself affects post-traumatic
symptoms, suggesting that chronic mental health problems after
the disaster would be addressable by economic support.

1.0mType of neighborhood /walkability

LDL (mg/dL)

Delayed PTSS

2.0

da

0

aff
ec

-5

e:

1.0

in
g

0.5

us

0.0

Ho

HDL (mg/dL)

-0.5

nd

-1.0

ag

-1.5

m

5

da

0

ily
/fr
ie

Triglycerides (mg/dL)

-5

in
g

-10

us

10

Ho

0

Persistent
Recovered in 2016

3.0

s

-10

4.0

om

-20

Persistent PTSS

5.0

ff
am

NonDisplaced

6.0

Odds ratio

Displaced

7.0

pt

Whole

Some people who lost their homes to the tsunami inthe coastal areas of Iwanuma were ﬁrst displaced totemporary housing, and then moved to public
permanent housing approximately 4 km further awayfrom the temporary housing. Shiba et al. (2020) foundthat moving from a place far from supermarkets,
restaurants, and pachinko parlors to a place near thosedestinations worsened the risks of metabolic
syndrome.
The JAGES analyzed survey data from 2010, 2013, and2016 of older adults in Iwanuma, which was linked
with the results of health check-up records. The
relationships between environmental changes
associated with moving and cardiometabolic proﬁleswere examined. Residential areas were rated on ascale of "high," "medium," and "low" based on thedensity of shops and other factors. Moving from "low"to "high" was associated with worse cardiometabolic
proﬁles: BMI increased by 0.46, waist circumference
increased by 1.8 cm, LDL cholesterol increased, andthere was a decrease in HDL cholesterol. BMI increased
only for females. Thus, the effects of efforts to maintainthe health of survivors, such as promoting physicalactivities, may be cancelled out by the adverse effect ofenvironmental changes associated with relocation.

ym

Waist Circumference(cm)

Lo
ss
o

BMI (kg/m2)

es

Diastolic Pressure (mmHg)

pr
es
siv

Systolic Pressure (mmHg)

Long-term Impact

Predictors of persistent versus delayed post-traumatic stress symptoms

De

Correlation between neighborhood environment and lifestyle-related diseases

33 Predictors of persistent mental health problems 6 years after disaster

Iwanuma Project

40

Kino S, Aida J, Kondo K, Kawachi I: Persistent mental health impacts of disaster. Five-year follow-up after the 2011 Great East Japan Earthquake and tsunami: Iwanuma Study. J
Psychiatr Res. 2021 Apr; 136:452-459. doi: 10.1016/j.jpsychires.2020.08.016. Epub 2020 Aug 23.

Shiba K, Hanazato M, Aida J, Kondo K, Arcaya M, James P, Kawachi I: Cardiometabolic proﬁles and change in neighborhood food and built environment among older adults: A natural experiment.
Epidemiology. 2020 Nov;31(6):758-767. doi:10.1097/EDE.0000000000001243.

Unemployment and deterioration of ﬁnancial status due to the earthquake affect persistent and delayed onset PTSS

32

Long-term Impact

Long-term relationship between a traumatic experience and health

The long-term health impacts of an earthquake may have been underestimated(n=4,857)

Analysis Method

Risk ratio (95% conﬁdence interval)

Bias adjustment
method 1

1.34 (0.96,1.68)

Bias adjustment
method 2

1.21 (0.70,1.69)

Bias adjustment
method 3

2.00 (1.21,2.87)

0.5

1.0

1.5

2.0

2.5

3.0

Shiba K, Kawahara T, Aida J, Kondo K, Kondo N, James P, Arcaya M, Kawachi I: Causal inference in studying the long-term health effects of disasters: Challenges
and potential solutions. Am J Epidemiol. 2021 Mar 17. doi:10.1093/aje/kwab064.

Conventional analytical methods do notappear to link loss of housing anddepressive symptoms.

2016

PTSS (n=106)

No PTSS (n=147)

PTSS (n=109)

No PTSS (n=1,913)

TrajectoryGroupsPersistent

Recovered (ref)DelayedNever (ref)The people who lost their homes had atwice as high risk of depressive symptoms
in 2016
Note: Bias adjustment method three assess the health effects of losing
one's house among a subset of the affected population (people who
would have participated in the survey 5.5 years later, regardless of whether
they had lost their homes).

Depression (n=504)

2010

2013

Several studies reported that trauma caused by disasters has long-term negative effects on health. However, analyzing data acquired after an earthquake using conventional statistical methods can lead tobias and underestimation. We therefore used follow-up data from about 4,800 survivors of the Great East Japan earthquake to compare the differences in the estimated long-term effects of disaster-related
home loss on health. The results showed the link between the traumatic experience of the disaster and subsequent health problems was likely underestimated. For instance, they demonstrated that people
who experienced home loss (versus no home loss) had a two times higher risk of depressive symptoms ﬁve and a half years after the earthquake. The result indicates that negative effects do not diminish in
the long-term; thus, continued health supports for survivors is necessary.

27

No PTSS (n=2,022)

1.21 (0.85,1.60)

Unadjusted bias

Risk ratio

PTSS (n=253)

2013

Depression (n=338)

No Depression (n=1,231)

No Depression (n=166)

Depression (n=168)

No Depression (n=1,063)

2016

Depression (n=258)

No Depression (n=80)

Depression (n=63)

No Depression (n=103)

Depression (n=83)

No Depression (n=85)

Depression (n=101)

No Depression (n=962)

TrajectoryGroupsPersistent

Recovered

Persistent

Recovered

Persistent

Recovered

DelayedNever

Risk of persistence

Risk of ﬂuctuation

Risk of symptoms persisting

Risk of delayed onset of symptoms

Few studies have tracked the long-term mental health outcomes following major disasters. Therefore, they sought to document the trajectories of depressive symptoms and PTSS in the aftermath of the2011 Great East Japan earthquake and tsunami. Among people without pre-disaster depressive symptoms, 13.6% had developed depressive symptoms 2.5 years after the disaster. Of these, half of those
had recovered and half had persisted at the 5.5-year follow-up. Exactly 11.1% of survivors reported PTSS in 2013; of these, 58% recovered by 2016, while 4.8% experienced delayed onset.
The experience of job loss and drop in subjective economic status appeared to exert a lingering inﬂuence on the persistence or delayed onset of PTSS.

28

Essay34 6-year followup study of the health impacts of residential relocation

Iwanuma ProjectLong-term Impact

Group relocation to disaster relief housing increases the risk of obesity and depression* p < 0.01

1.60
1.40

1.50*

Regression Coefﬁcient

1.20
1.00
0.80
0.79*

0.60
0.40

0.19

0.20
0.00

-0.10

-0.20
Relocating to disaster
relief housing

Relocating topermanent housing

Relocating to disaster
relief housing

BMI

Relocating topermanent housing

Depression
Hikichi H, Aida J, Kondo K, Kawachi I. Six-year follow-up study of residential displacement and health outcomes following the 2011 Japan Earthquake andtsunami. Proc Natl Acad Sci U S A. 2021 Jan 12;118(2): e2014226118. doi: 10.1073/pnas.2014226118.

Studies examining the long-term health consequences of residential displacement following large-scale disasters remain sparse. Following the 2011 Japan Earthquake and Tsunami, victims who lost theirhomes were resettled by two primary means: 1) group relocation to public housing or 2) individual relocation, in which victims moved into public housing by lottery or arranged for their own
accommodation. Little is known about how the speciﬁc method of residential relocation affects survivors’ health. We examined the association between residential relocation and long-term changes inmental and physical well-being. Our baseline assessment predated the disaster by 7 months. Two follow-up surveys were conducted approximately 2.5 and 5.5 years after the disaster to ascertain thelong-term association between housing arrangement and health status. Group relocation was associated with increased body mass index and depressive symptoms at 2.5-year follow-up but was no longer
signiﬁcantly associated with these outcomes at 5.5-year follow-up. Individual relocation at each follow-up survey was associated with lower instrumental activities of daily living as well as a higher risk ofcognitive impairment. Our ﬁndings underscore the potential complexity of long-term outcomes associated with residential displacement, indicating both positive and negative impacts on mental versus
physical dimensions of health.

JAGES HEART 2019Conclusions of Iwanuma Project 2021.6

Development of disaster preparedness"visualization" system

The Iwanuma Project compared data obtained before the disaster with thatobtained afterwards to gain several insights and to answer the question of how much

JAGES built a "visualization" system for regional analysis using health and lifestyle survey data.
The name of the system is "Community-based Management Support System (JAGES HEART)."

the reduction of social capital due to a major natural disaster affects peoples' health.

It performs visualizations like those given below
Participants in disaster andemergency drills (%)

Which regions arevulnerable to disasters?

The more social capital a community has,the more prepared it is for disaster
Correlation Coefﬁcient : 0.4924

100

50

25

38.5-95.5%
029Comparison between primary school
districts and municipalities

Percentage of participants in
disaster and emergency drills

75

90

75

60

45

18

19

20

Social capital (Mutual aid)

21

I

W

A

N

U

M

A

P

R

O

J

E

C

T

Conclusion

Implications of the Iwanuma Project-Steps to maintain social connections-

We found numerous links between areas with rich social capital(connections between people) and better health pre- and post-disaster.
It suggests that increasing social capital before a disaster can lesad to disaster mitigation

The higher the pre- and post-disaster social capital,
the lower the health risk after a disaster.

Pre- and post-disaster factors that increase the riskof health deterioration after a disaster:
Risk factors that aggravated health after the earthquake

Pre-earthquake

Factors before the earthquake● Distance from coastline (mortality risk on day of disaster)● Severe depression before the earthquake (mortality risk on the day of the earthquake)● Dependence on others before the earthquake (mortality risk from the day after the earthquake)

Post-earthquake

Pre-disaster(Preparedness stage)
Factors for disastermitigation

Down!

● Damage to the house (depression, PTSD, loss of teeth, loss of independence, risk of dementia)

Communication● Loss of loved ones (PTSD)

Post-disaster
Factors for disastermitigation● Loss of loved ones

● Declining economic conditions (loss of teeth)● Difﬁculty in seeking medical attention immediately after the disaster(depression, declining degree of independence)

Communication

Neighborhood
Relationships

with group relocation

Mortality
Group Physical Exercise

2 Lottery (compared to group) allocation was associatedwith less providing/receiving social support.

（Koyama, 2014 No. 14）

0.04

0.053(p=0.013)

0.02
0.00
-0.02
-0.04
-0.06

Individual relocation
Group Relocation-0.039(p=0.035)

Relationship between relocation method
and social connection(n=3,421)

31

Percentage of people without social support

Changes in Social Ties Scores

0.06

30%

Dementia

Down!

Longitudinal panel data for post-disaster relocation of socially connected groups 2010–2013（Hikichi, 2017 No. 6）

Depression

Down!

Method of relocation to temporary housing
post-disaster affects health
1 Social ties increase

Down!

Earthquake

Neighborhood
Relationships● Relocation to temporary housing (depression)

PTSD

Group
Relocation

Factors after the earthquake● Facing the disaster without having experienced adversity (PTSD)

Iwanuma Project

Lottery Allocation

Lottery Allocation

Group Physical Exercise

・Neighborhoods with strong pre-earthquake ties are likely to have lower post-earthquake health risks.
・Group relocation of communities, rather than individual or lottery relocation, lowers post-disaster health risks.

25%

Group Allocation

20%
15%
10%

Increasing social capital before and after the disasteris the key to disaster mitigation.

Group Allocation

5%0%

Receivingsocial support

Implications of the Iwanuma Project

Providingsocial support

・Developing social capital in daily life in preparation for earthquakes and disasters
・Taking measures such as group relocation to maintain social capital after the disaster
32

Conclusion

Iwanuma Project

The higher the social capital, the higher the resilience to disaster• Developing social capital in daily life in preparation for earthquakes and disasters.
• Taking measures, such as group relocation, to maintain social capital after the disaster.

Three typesof Social
CapitalExternal Connections

Social capital can be strengthened byallowing people from different regions tointeract, instead of staying within one
region.

33

Exercise and Hobbies

Social capital can be improved among
local residents through exercise andhobby group activities, festivals, andother events in which participation canoccur.

Temporary Housing

Group relocation to temporary housing after anearthquake is more likely to bring people closer
together and has less impact on health whencompared to individual relocation by lottery.

Public Space

Bonding Type

Refers to the bond between people who have something in common.
While strong bonds are created inside groups, there is also an aspect of exclusivity.

Bridging Type

Bonding type refers to ties within the same area, whereas the bridging type refers to looser
ties with the outside world.
Connecting with the external world provides added information and resources.

Linking TypeThe link between the general public and authority represented by the administration.
It is the relationship of trust that exists between people who cross the boundaries ofsocial power and authority.

It is possible to provide public spaces that areaccessible to a wider range of local residents byfocusing on places where people are likely tocongregate, such as town halls, community
centers, schools, and parks.

Places for Experience

In addition to creating places, it isimportant to offer a variety of events,
experiences, and activity programs inparks and sports facilities.

Neighborhood Environment

The study demonstrated that aneighborhood environment in which local
residents can go out, exercise, communicate,and shop on a daily basis has a positive
impact on health.

34