Articles

Ikigai and subsequent health and wellbeing among
Japanese older adults: Longitudinal outcome-wide
analysis
Sakurako S. Okuzono,a,b,1* Koichiro Shiba,a,c,d,1 Eric S. Kim,e Kokoro Shirai,f Naoki Kondo,g Takeo Fujiwara,b Katunori Kondo,h,i
Tim Lomas,d Claudia Trudel-Fitzgerald,a,j Ichiro Kawachi,a and Tyler J. VanderWeelec,d,kaDepartment of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health, 677 Huntington Ave., MA, USA
Department of Global Health Promotion, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, Japanc
Department of Epidemiology, Harvard T.H. Chan School of Public Health, 677 Huntington Ave., MA, USAd
Human Flourishing Program, Harvard Institute for Quantitative Social Science, 1737 Cambridge St., MA, USAe
Department of Psychology, University of British Columbia, Vancouver BC V6T 1Z4, CanadafDepartment of Public Health, Graduate School of Medicine, Osaka University, 1-1 Yamadaoka, Suita, Osaka, Japang
Department of Social Epidemiology, Kyoto University School of Public Health, Yoshidahonmachi, Sakyo Ward, Kyoto, Japanh
Department of Gerontological Evaluation, National Center for Geriatrics and Gerontology, 7-430 Moriokacho, Obu, Aichi,
Japani
Department of Social Preventive Medical Sciences, Center for Preventive Medical Sciences, Chiba University, 1-33 Yayoicho,
Inage Ward, Chiba, Japanj
Lee Kum Sheung Center for Health and Happiness, Harvard T.H. Chan School of Public Health, 677 Huntington Ave., MA,USA
kDepartment of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, 677 Huntington Ave., MA, USAb

Summary
Background Having a purpose in life has been linked to improved health and wellbeing; however, it remains
unknown whether having “Ikigai”—a related but broader concept in Japan—is also beneficial for various physicaland psychosocial outcomes.
Methods Using data from a nationwide longitudinal study of Japanese older adults aged ≥65 years, we examined
the associations between having Ikigai in 2013 and a wide range of subsequent outcomes assessed in 2016 across
two databases (n = 6,441 and n = 8,041), including dimensions of physical health, health behavior, psychological distress, social wellbeing, subjective wellbeing, and pro-social/altruistic behaviors. We adjusted for sociodemographic
characteristics and the outcome values (whenever data were available) in the prior wave (2010).

The Lancet Regional
Health - Western Paciﬁc2022;21: 100391
Published online xxx
https://doi.org/10.1016/j.
lanwpc.2022.100391

Findings Having Ikigai (vs. not having Ikigai) was associated with a 31% lower risk of developing functional disability[95% confidence interval (CI) for risk ratio: 0.58, 0.82] and 36% lower risk of developing dementia [95% CI for risk
ratio: 0.48, 0.86] during the three-year follow-up. Having Ikigai was associated with decreased depressive symptoms
and hopelessness as well as higher happiness, life satisfaction, instrumental activity of daily living, and certain social
outcomes (e.g., more frequent participation in hobby clubs). Some of these associations were stronger for men than
women, and among individuals with high socioeconomic status (p-values for effect measure modification < 001).
Interpretation Having Ikigai may promote health and wellbeing outcomes among Japanese older adults, but particularly men and individuals with high socioeconomic status.
Funding NIH, John Templeton Foundation, JSPS, AMED, MHLW, MEXT, and WPE Foundation.
Copyright Ó 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Keywords: Ikigai; Purpose in life; Aging; Wellbeing; Asia

Introduction*Corresponding author at: Department of Social and Behavioral Sciences, Harvard T.H. Chan School of Public Health,677 Huntington Ave., MA, USA.
E-mail address: sshiba@hsph.harvard.edu (S.S. Okuzono).
1
These authors contributed equally to this work.

www.thelancet.com Vol 21 Month April, 2022

Public health and epidemiology have focused on reducing disease risk factors (e.g., smoking) to promote population health.1 In contrast, growing evidence suggeststhat cultivating positive psychological assets—factors
related to positive psychosocial and spiritual aspects of1

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Research in context
Evidence before this study
While there is a wealth of evidence linking having a purpose in life to longevity and improved health/wellbeingof older adults, little is known about whether having Ikigai—a related but not identical psychological concept—is likewise beneﬁcial for healthy aging. We searched
PubMed using the search term “Ikigai”, “health”, “wellbeing”, with no language restrictions, from Jan 1979 to
Jan 2021. We found only a few studies that investigatedthe longitudinal association between Ikigai, health, andwellbeing. These studies examined a narrow range ofhealth/wellbeing outcomes and lacked rigorous adjustment for confounding and reverse causation.
Added value of this study
To our knowledge, this is the ﬁrst study to holisticallyevaluate associations between Ikigai and a wide rangeof subsequent health and wellbeing, including dimensions of physical health, health behavior, psychologicaldistress, social wellbeing, subjective wellbeing, and prosocial/altruistic behaviors. We leveraged a large, nationwide, longitudinal cohort study of Japanese older adults
and adjusted for a rich set of potential confounders,
including pre-baseline outcome values to address
reverse causation. This study demonstrated that having
Ikigai was longitudinally associated with some favorable
physical health outcomes (lower risk of developing
functional disabilities and dementia), reduced psychological distress (depressive symptoms and hopelessness), and improved subjective wellbeing (happinessand life satisfaction). Moreover, our study revealed abidirectional association between Ikigai and psychological distress. Some of these associations were stronger
for men and individuals with high socioeconomic
status.
Implication of all the available evidence
Although more research is needed to understand why
Ikigai appeared less beneﬁcial for some outcomes andamong women and individuals with low SES, Ikigai may
be a promising modiﬁable positive psychological asset,
which can supplement the current public health efforts
to reduce risk factors to promote health and wellbeing.

life—can also contribute to improved health and wellbeing.2 One potentially modifiable psychological asset ispurpose in life, which is the extent to which individuals
perceive their lives as having aims that generate and prioritize their pursuits and actions.3,4 In studies of the
US-based populations, higher levels of purpose in life
have been linked to greater subjective wellbeing (e.g.,life satisfaction), healthier behaviors, and reduced morbidity and mortality risk.5,62

Ikigai, broadly defined as “what makes life worth living,” is a well-accepted psychological concept in the Japanese culture.7 In efforts aimed at promoting longer
and healthier lives, the Japanese government recently
decided that increasing Ikigai among older adults is apolicy priority.8 Although Ikigai and purpose in life
share many features, Ikigai is broader: while purpose inlife refers to one aspect of eudaimonic wellbeing (i.e.,
wellbeing that pertains to internal virtue and pursuing
human capacity),3 Ikigai is characterized not only by
purpose in life but also by other aspects of eudaimonic
wellbeing (e.g., personal growth) as well as features ofhedonic wellbeing (i.e., pleasure and satisfaction which
do not necessarily result from virtuous activities).2,9,10
For example, some people may derive their Ikigai
through activities that promote purpose in life such as
volunteering, others may cultivate Ikigai by fulfilling
one’s own need (e.g., reading books to satisfy curiosity)or simply indulging in pleasure (e.g., enjoying drinks
with peers). Despite the nuanced conceptual differences
between Ikigai and purpose in life, most available longitudinal evidence focuses predominantly on purpose inlife, rather than Ikigai, in relation to future health andwellbeing. Emerging evidence from Ikigai studies suggest that having Ikigai is associated with a reduced riskof cardiovascular disease, mortality, and functional disability.11−18
These past studies provided important insights about
the potential health benefits of Ikigai; however, threemethodological limitations remain unaddressed. First,
several of these studies did not include important potential confounders (e.g., depressive symptoms). Second,even though these studies harnessed longitudinal data,
they inadequately accounted for pre-baseline health conditions, so that the potential for reverse causation (i.e.,
better health and wellbeing leading to greater Ikigai, notvice versa) could not be precluded. Lastly, althoughhealth is a multidimensional construct (often defined as“a state of complete physical, psychological, and social
wellbeing” rather than the mere absence of diseases),
the existing evidence on the health benefits of Ikigai is
restricted to physical health outcomes.19,20 Assessing amore comprehensive set of outcomes simultaneously
can facilitate comparisons of the directions and magnitudes of the Ikigai-health association across outcomesand provide a more holistic picture (e.g., Ikigai may bebeneficial for some outcomes but have a detrimental
impact on others). Such analytic approach can also prevent selective reporting of study findings and publication bias.1,21
To address these gaps, we applied an outcome-wide
approach to examine the prospective associations of Ikigai with multiple health and wellbeing outcomes using
the nationwide longitudinal sample of Japanese older
adults.20,22 To reduce the concerns about unobserved
confounding and reverse causation, we leveraged the

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rich panel structure of the data and rigorously adjusted
for pre-existing health conditions such as depression.

MethodStudy sample
We used data from the Japan Gerontological Evaluation
Study (JAGES), a nationwide longitudinal survey ofphysically and cognitively independent communitydwelling older adults aged ≥ 65 years in Japan.23 In
2010, the JAGES was established and collected data onsociodemographic factors, health conditions, and wellbeing from 78,873 individuals in 19 municipalities inJapan (response rate: 69.3%). In 2013 (our study’s baseline wave), the JAGES conducted the follow-up survey(n = 54,283 individuals; follow-up rate = 68.8%) andrandomly selected 20% of the participants to fill out aquestionnaire which contained an Ikigai assessment(n = 10,867). We obtained two analytic samples by linking these 10,867 individuals either to the second followup wave of the main survey in 2016 (n = 6,441; followup rate = 59.3%) or to the national long-term care insurance database containing information on the onset of
all-cause mortality, functional disability, and dementia
through 2016 (i.e., n = 8,041; follow-up rate = 74.0%).
We used the two different analytic samples to increase
our sample size. Participation in the 2016 follow-up
wave was not necessary for the analysis of the outcomesfrom the long-term care insurance database. See
Figure 1 for the flow chart.

Measures
Ikigai. Participants reported whether they had Ikigai intheir life at the time of the survey in 2013. The survey
question asked, “Do you have Ikigai?” with a binary
response option (yes or no).
Outcomes. We examined 30 health and wellbeing outcomes in 2016, including physical health (all-cause
mortality, functional disability,22,24 dementia,25 noremaining natural teeth, self-rated health, flu infectionin the past year, pneumonia infection in the past year,
and instrumental daily activities of living [IADL]),26
health behaviors (current smoking, body mass index[BMI], sedentary lifestyle, insomnia, flu shot in the past
year, health check-up in the past year), psychologicaldistress (depressive symptoms 27 and hopelessness),social wellbeing (participation in a hobby group, sports
group, or senior citizens club, frequency of meeting
friends, number of friends seen per month, emotionalsocial support, and care social support), subjective wellbeing (happiness, and life satisfaction), and pro-social
behaviors (volunteering and sharing skills andwww.thelancet.com Vol 21 Month April, 2022

experiences). We chose these outcomes based on
VanderWeele’s multidimensional concept of humanflourishing as a framework.28 Although other theorizing and measures of multidimensional well-being exist,
we chose this framework as it covers physical health inaddition to a number of domains shared by the various
frameworks.29−32 Table S1 provides further details
about each outcome measurement.

Covariates. All pre-baseline covariates were drawn fromthe 2010 survey three years before the Ikigai assessment. These covariates included age, gender, marital
status, living alone, education, job, equivalized household income, the number of self-reported health conditions, and the number of major life events in the past
year. To reduce the possibility of reverse causation (i.e.,
health and wellbeing affecting having Ikigai), we also
controlled for prior values of all outcomes from the2010 survey, except for the following outcomes because
the data were not available: sedentary lifestyle, flu shotin the past year, infection in the past year (flu, or pneumonia), insomnia, happiness, and sharing skills andexperiences.

Statistical analysis
We used a longitudinal outcome-wide analytic
approach, which enables a holistic assessment of the
impact of a single exposure on a wide range of outcomes
and has several other methodological advantages (e.g.,less susceptible to “p-hacking”—deliberately or unconsciously changing analytic approaches to obtain resultswith p < 0.05—and publication bias).20,21 We fitted aseparate regression model for each outcome andrepeated the analysis of individual outcomes one byone. To estimate the associations between Ikigai andeach outcome adjusting for the pre-baseline covariates
and outcomes in the pre-baseline wave, we used the
doubly-robust targeted maximum likelihood estimation.33 This approach estimates both the exposure (propensity score) model and outcome model and, under
the assumption of no unmeasured confounding, yields
unbiased estimates for the average treatment effects ifeither of the two models is consistently estimated.
Hence, the approach improves statistical estimation,
not causal identification, and is more robust to model
misspecification. We estimated risk ratios (RRs) for thebinary outcomes. All continuous outcomes were standardized (mean = 0, standard deviation = 1), so theeffect estimates can be interpreted as a standard deviation change in the outcome variable. We used Bonferroni correction to account for multiple testing.
We conducted three additional analyses. First, we
examined potential antecedents of Ikigai. We used amodified Poisson regression with robust standard errors
to estimate the RR for the association between each of3

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Figure 1. Flow of Samples Selection (n=6,441 for the Outcomes Based on the Follow-up Survey in 2016 and n=8,041 for the Outcomes Based on the Long -term Care Insurence Database).
LTCI: Long-term care insurence.

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the pre-baseline covariates and Ikigai in 2013, simultaneously controlling for all other covariates.34 Second, toevaluate the robustness of our effect estimates tounmeasured confounding, we calculated E-values foreach Ikigai-outcome association.35 E-values quantify theminimum strength of association on the RR scale thatan unmeasured confounder would need to have withboth the exposure and outcome, above and beyond theadjusted covariates, to explain away the observed association. Third, given emerging evidence suggesting
potential heterogeneity in Ikigai-health associations, we
performed subgroup analyses for the outcome-wide
associations and antecedents of Ikigai to examine
whether the associations differ by socioeconomic status(SES) and gender.36−38 We defined binary SES asreporting both low educational attainment (< 10 yearsof schooling) and low equivalized household income(< 2 million yen/year: approximately 18,400 USD as ofMarch 1, 2021) in the 2010 wave, which follows benchmarks set by previous studies in Japan.39,40 We formallytested for effect measure modification by comparing thesubgroup-specific estimates, on both additive (difference in standardized differences for continuous outcome and difference in risk differences for binary
outcomes) and multiplicative scales (ratio of RRs forbinary outcomes).
We used multiple imputation by chained equations
to impute missing data on all variables, using the mice
R package.41 After generating five imputed datasets, we
performed the analyses described above using each
imputed dataset and combined the results across imputations (more details on missing data and our imputation approach is available in Table S2 and Appendix).
All analyses were conducted in R, version 3.6.0.

Role of the funding source
The founders on the study had no role in study design,
data collection, data analysis, data interpretation, or
writing of the report.

Results
Table 1 summarizes the pre-baseline characteristics ofthe study sample linked to the 2016 wave (n = 6,411)
according to Ikigai status in 2013. Compared to those
without Ikigai (n = 776), people with Ikigai (n = 5,205)
tended to be married, highly educated, and currently
working. Having Ikigai was also associated with better
pre-baseline levels of all health and wellbeing except forbody mass index. The same trends were found for the
pre-baseline characteristics of the study sample linked
to the national long-term care insurance record(n = 8,041; Table S3).
Table 2 shows the estimated standardized differences in the continuous outcomes and RRs for binary outcomes comparing those with versus without Ikigai,

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controlling for all aforementioned covariates. Having
Ikigai was strongly associated with lower risk of developing functional disabilities, higher IADL, fewer depressive symptoms, lower risk of having a sense ofhopelessness, more frequent participation in hobby
clubs, higher chance of reporting life satisfaction, andmore frequent sharing of skills and experiences withothers. These associations remained below the p < 0.05
threshold even after accounting for multiple testing via
Bonferroni correction. We also found modest evidence
for the associations between having Ikigai and lower
risk of dementia, sedentary lifestyle, and insomnia,
more frequent participation in sport clubs, and higher
likelihood of having emotional social support; however,these additional associations were not below thep < 0.05 threshold after Bonferroni correction for multiple testing.
While the results were generally similar across levelsof SES (Table S4) for most outcomes (e.g., all-cause
mortality), there was some evidence of effect measuremodification such that Ikigai is more strongly associatedwith better physical health outcomes in the high SES
group. In subgroup analysis by gender (Table S5), we
observed associations between Ikigai and physicalhealth outcomes only among men. The association
between Ikigai and all-cause mortality was modest in
the whole sample; but the evidence for an association
was stronger among men, although this did not reachthe p < 05 threshold after Bonferroni correction. We
also found evidence of effect measure modification foroutcomes in other domains (e.g., psychological distress)and evidence for associations with greater wellbeing
tended to be stronger among men.
Of the covariates assessed in 2010, greater depressive symptoms, hopelessness, and female gender werestrong predictors of not having Ikigai in 2013 (Table 3).
There was modest evidence that having emotional social
support, experiencing fewer major life events in thepast year, greater IADL, and not being a current
smoker (all assessed in 2010) were predictive of having Ikigai in 2013; but all other measured covariates
in 2010 were not antecedents of Ikigai in 2013. We
observed similar results when the analysis for antecedents of Ikigai was stratified by SES (Table S6) andby gender (Table S7).
The calculated E-values (Table 4) suggest that someof the observed associations of having Ikigai with subsequent health and wellbeing outcomes were moderately
robust to an unmeasured confounder. For example, toexplain away the association between having Ikigai andthe risk of developing functional disability during thefollow-up, an unmeasured confounder associated withboth Ikigai and the functional disability by the RR of
2.26—above and beyond the adjusted covariates—could
suffice, but weaker joint unmeasured confounding associations could not; to shift the confidence interval toinclude the null value, unmeasured confounding5

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Pre-baseline characteristics

Ikigai in 2013a

Overalln = 6,411

Non = 776Yesn = 5,205

71.9 (5.1)

71.8 (4.9)

71.8 (5.0)

p-valuebSociodemographic factors
Age, mean (SD)Men

2,931 (46%)

309 (40%)

2,460 (47%)

Women

3,510 (54%)

467 (60%)

2,745 (53%)

Married

4,771 (76%)

535 (71%)

3,940 (77%)

Widowed

1,168 (19%)

145 (19%)903 (18%)

Divorced

187 (3.0%)

32 (4.3%)

141 (2.8%)

Single115 (1.8%)

27 (3.6%)

79 (1.6%)

Other

35 (0.6%)

12 (1.6%)

23 (0.5%)703 (11%)116 (15%)514 (10%)<0.001

Marital status, n (%)

Living alone, n (%)<0.001<0.001

Education, n (%)<6 years

87 (1.4%)

16 (2.1%)

62 (1.2%)

6-9 years

2,691 (43%)

409 (54%)

2,041 (40%)

10-12 years

2,271 (36%)

230 (31%)

1,905 (37%)≥13 years

1,204 (19%)

93 (12%)

1,057 (21%)

Other

28 (0.4%)

4 (0.5%)22 (0.4%)

1,553 (27%)

154 (23%)

1,318 (28%)

Job, n (%)
Working

0.923<0.001

Gender, n (%)

0.006

Retired

3,521 (62%)

438 (64%)

2,868 (61%)

Never worked

644 (11%)88 (13%)499 (11%)Equivalized household income (10,000 yen), mean (SD)151 (93)128 (86)

156 (94)<0.001

Number of life events in the past year, mean (SD)0.82 (0.92)

0.88 (0.95)

0.81 (0.91)

0.071

Physical health
Number of health conditions, mean (SD)1.44 (1.38)

1.71 (1.53)

1.39 (1.35)<0.001

No remaining natural teeth, n (%)

620 (9.9%)106 (14%)449 (8.9%)<0.001

Good self-rated health, n (%)

5,489 (87%)

558 (74%)

4,564 (89%)<0.001

Instrumental Activity of Daily Living, mean (SD)11.9 (1.53)

11.2 (1.92)

12.0 (1.42)<0.001

Current smoker, n (%)

593 (10%)101 (14%)457 (9.6%)<0.001

Body mass index, mean (SD)23.1 (5.09)

22.9 (3.20)

23.1 (4.66)

0.3

Participating health check-up in the past year, n (%)

4,191 (67%)

440 (59%)

3,485 (69%)<0.001

Depressive symptoms, mean (SD)2.97 (3.00)

6.43 (3.70)

2.43 (2.49)<0.001

Hopelessness, n (%)

1,031 (17%)

375 (51%)565 (11%)<0.001Frequency of participation in hobby clubs, mean (SD)2.40 (1.57)

1.96 (1.47)

2.48 (1.58)<0.001Frequency of participation in sport clubs, mean (SD)2.00 (1.58)

1.65 (1.33)

2.07 (1.61)<0.001Frequency of participation in senior clubs, mean (SD)1.49 (1.01)

1.38 (0.88)

1.50 (1.02)

0.004

Frequency of meeting friends, mean (SD)3.85 (1.47)

3.41 (1.49)

3.91 (1.46)<0.001

Health behaviors

Psychological distress

Social wellbeing

Number of friends I met last month, mean (SD)2.27 (1.25)

2.74 (1.31)

2.19 (1.23)<0.001

Emotional social support, n (%)

5,807 (95%)

652 (88%)4,764 (96%)<0.001

Care social support, n (%)

5,864 (96%)

659 (89%)

4,810 (97%)<0.0015,235 (83%)

422 (56%)

4,473 (87%)<0.0011.43 (0.98)

1.26 (0.78)

1.46 (1.00)<0.001

Subjective wellbeing
Life satisfaction, n (%)
Pro-social/altruistic behaviors
Frequency of volunteering, mean (SD)

Table 1: Pre-baseline Demographic Characteristics in 2010 Stratiﬁed by Ikigai Among the Analytic Sample for the Analysis of the
Outcomes from the JAGES Survey (n = 6,441).
ab

6

Sample sizes for the Ikigai strata in this table do not add up to the overall sample size (n = 6,441) because of missing in the Ikigai variable.
P-values were calculated using Pearson’s Chi-square test for categorical variables and Wilcoxson rank sum test for continuous variables.

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Outcome

b

RR

95%CI
Lower

Upper

P-value

Sig.b

Physical healthAll-cause mortalityc

0.85

0.60

1.19

0.328

N.S.

Functional Disability (Any levels)c

0.69

0.58

0.82

<0.001***

Functional Disability (Level 1 or greater)c

0.67

0.54

0.83

<0.001***

Functional Disability (Level 2 or greater)c

0.71

0.53

0.96

0.027

*

Functional Disability (Need support)c

0.70

0.54

0.92

0.011

*

Dementiac

0.64

0.48

0.85

0.002

**

No remaining natural teeth

0.92

0.74

1.15

0.464

N.S.

Good self-rated health

1.05

1.00

1.10

0.070

N.S.

0.10

0.28

<0.001***

Instrumental Activity of Daily Living

0.19

Health behaviors
Current smoker
Body mass index

1.10
0.01

0.82

1.48

0.519

N.S.

-0.05

0.07

0.766

N.S.
*

Sedentary lifestyle

0.62

0.42

0.92

0.018

Flu shot in the past year

1.00

0.93

1.07

0.902

N.S.

Infection in the past year (ﬂu)

1.42

0.66

3.06

0.362

N.S.

Infection in the past year (pneumonia)

1.59

0.51

5.03

0.423

N.S.

Participating health check-up in the past year

1.03

0.94

1.13

0.468

N.S.

Insomniad

0.55

0.34

0.89

0.014

*

-0.68

-0.48

<0.001

***

0.43

0.37

0.51

<0.001***

Psychological distress
Depressive symptoms-0.58

Hopelessness
Social wellbeing
Frequency of participation in hobby clubs

0.19

0.09

0.28

<0.001***Frequency of participation in sport clubs

0.09

0.00

0.17

0.047

*

Frequency of participation in senior clubs

0.03

-0.09

0.14

0.645

N.S.

Frequency of meeting friends

0.07

-0.02

0.15

0.114

N.S.

Number of friends I met last month

0.08

N.S.

0.00

0.17

0.050

Emotional social support

1.03

1.00

1.06

0.033

*

Care social support

1.03

0.98

1.02

0.742

N.S.

0.33

0.52

<0.001

***

1.09

1.21

<0.001***

Subjective wellbeing
Happiness

0.43Life satisfaction

1.14

Pro-social/altruistic behaviors
Frequency of volunteering

0.07

-0.04

0.17

0.201

N.S.

Frequency of sharing skills and experiences

0.17

0.08

0.26

<0.001***aTable 2: Associations between Ikigai and subsequent health and well-being, Japan gerontological evaluation study (n = 6,441) .
CI, confidence interval; Sig., significance; N.S., not significant; RR, risk ratio; b, standardized difference.
a
We estimated standardized differences for the continuous outcomes and risk ratios for the binary outcomes, using the doubly robust targeted maximum
likelihood estimation. We adjusted for pre-baseline covariates (age, gender, marital status, living alone, education, job, equivalized household income, the number of self-reported health conditions, and the number of major life events in the past year) as well as prior levels of outcomes wherever data were available toaddress reverse causation.
b*p<0.05 before Bonferroni correction; ** p<0.01 before Bonferroni correction; *** p<0.05 after Bonferroni correction (the p-value cutoff for Bonferroni
correction is p = 0.05/30 outcomes = p <0.0017).
c
The analytic sample size was n = 8,951 for the following outcomes: all-cause mortality, functional disabilities, and dementia.
dItems for insomnia were available only in the submodule questionnaire in 2016 that was distributed to randomly selected 826 individuals.

associations of 1.74-fold each could suffice, but weakerconfounding could not.

Discussion
In this nationwide longitudinal study of Japanese older
adults, our main findings are four-fold. First, Ikigai waswww.thelancet.com Vol 21 Month April, 2022

associated with some favorable physical health outcomes such as lower risk of developing functional disabilities, particularly among men and those fromhigher SES backgrounds. Second, Ikigai was also associated with reduced psychological distress (depressive
symptoms and hopelessness) and improved subjective
wellbeing (happiness and life satisfaction), though7Articles

Predictors in 2010

RRa

95% CI
Lower

Upper

P-valueSig. bSociodemographic factors
Age

1.01

0.99

1.02

0.366

N.S.

Women (vs. Men)

0.95

0.93

0.98

<0.001***

Widowed

1.01

0.98

1.04

0.496

N.S.

Divorced

1.06

0.99

1.13

0.086

N.S.

Single

0.98

0.88

1.09

0.754

N.S.

Other

0.85

0.70

1.04

0.119

N.S.

Living alone

0.97

0.93

1.02

0.219

N.S.

Marital status (vs. Married)

Education (vs. <6 years)
6-9 years

0.98

0.87

1.11

0.742

N.S.

10-12 years

1.01

0.89

1.15

0.864

N.S.

≥13 years

1.01

0.89

1.14

0.894

N.S.

Other

0.98

0.81

1.18

0.795

N.S.

Retired

1.00

0.97

1.04

1.000

N.S.

Working

1.01

0.97

1.06

0.520

N.S.

Equivalized household income (10,000 yen)

1.00

0.99

1.01

0.424

N.S.

Number of major life events in the past year

1.01

1.00

1.02

0.033

*

Job (vs. Never worked)

Physical health
Number of health conditions

1.01

0.99

1.02

0.277

N.S.

No teeth

0.98

0.95

1.02

0.350

N.S.

Good self-rated health

1.00

0.97

1.05

0.831

N.S.

Instrumental Activity of Daily Living

1.02

1.00

1.04

0.039

*

Current smoker

0.96

0.93

1.00

0.027

*

Body mass index

1.00

0.99

1.02

0.955

N.S.

Participating health check-up in the past year

1.01

0.99

1.03

0.516

N.S.

Health behaviors

Psychological distress
Depressive symptoms

0.86

0.84

0.89

<0.001***

Hopelessness

0.88

0.84

0.93

<0.001***Frequency of participation in hobby clubs

1.00

0.99

1.02

0.454

N.S.

Frequency of participation in sport clubs

1.00

0.98

1.01

0.556

N.S.

Frequency of participation in senior clubs

1.01

1.00

1.02

0.206

N.S.

Frequency of meeting friends

1.00

0.99

1.01

0.881

N.S.

Social wellbeing

Number of friends I met last month

1.01

1.00

1.02

0.187

N.S.

Emotional social support

1.10

1.03

1.19

0.008

**

Care social support

1.09

1.00

1.19

0.051

N.S.

1.04

1.00

1.09

0.083

N.S.

1.00

0.98

1.01

0.387

N.S.

Subjective wellbeing
Life satisfaction
Pro-social/altruistic behaviors
Frequency of volunteering

Table 3: Antecedents of Ikigai in 2013, Japan gerontological evaluation study (n = 6,441).
CI, confidence interval; Sig., significance; N.S., not significant; RR, risk ratio.
a
We used a modified Poisson regression with robust standard errors was used to estimate the prevalence ratio for the association between each of the predictors in 2010 and Ikigai in 2013, simultaneously controlling for all other covariates.
b*p<0.05 before Bonferroni correction; ** p<0.01 before Bonferroni correction; *** p<0.05 after Bonferroni correction (the p-value cutoff for Bonferroni
correction is p = 0.05/33 predictors = p <0.002)

evidence for some associations were stronger among men.
Third, evidence for associations with outcomes in otherdomains (health behavior, social wellbeing, and character8

and virtue) were modest, mixed, or inconclusive. Fourth,
only a few pre-baseline characteristics such as gender andpsychological distress predicted subsequent Ikigai.

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Articles

E-value for point estimateb

E-value for conﬁdence limitc

All-cause mortalityd

1.77

1.00

Functional Disability (Any levels)d

2.26

1.74

Functional Disability (Level 1 or greater)d

2.30

1.67

Functional Disability (Level 2 or greater)d

2.08

1.16

Functional Disability (Need support)d

2.17

1.25

Dementiad

2.50

1.60

No remaining natural teeth

1.39

1.00

Good self-rated health

1.27

1.00

Instrumental Activity of Daily Living

1.66

1.42

Current smoker

1.43

1.00

Body mass index

1.10

1.00

Sedentary lifestyle

2.61

1.39

OutcomePhysical health

Health behaviors

Flu shot in the past year

1.07

1.00

Infection in the past year (ﬂu)

2.19

1.00

Infection in the past year (pneumonia)

2.57

1.00

Participating health check-up in the past year

1.22

1.00

Insomniae

3.07

1.51

Psychological distress
Depressive symptoms

2.75

2.45

Hopelessness

4.07

3.35

Frequency of participation in hobby clubs

1.66

1.40

Frequency of participation in sport clubs

1.38

1.05

Frequency of participation in senior clubs

1.18

1.00

Frequency of meeting friends

1.32

1.00

Number of friends I met last month

1.37

1.03

Emotional social support

1.21

1.06

Care social support

1.06

1.00

2.31

2.05

Frequency of volunteering

1.32

1.00

Frequency of sharing skills and experiences

1.60

1.36

Social wellbeing

Subjective wellbeing
Happiness
Pro-social/altruistic behaviors

Table 4: Robustness to Unmeasured Confounding (E-values) of Associations Between Ikigai and Subsequent Health and Well-being, Japana
Gerontological Evaluation Study (n = 6,441) .
a

For information on calculation on E-values, see VanderWeele and Ding (2017) for the formula.
E-values for effect estimates are the minimum strength of association on the risk ratio scale that an unmeasured confounder would need to have with boththe exposure and the outcome, above and beyond the measured covariates, to fully explain away the observed associations of Ikigai with the outcomes.
cE-values for the 95% confident interval limit closest to the null denote the minimum strength of association on the risk ratio scale that an unmeasured
confounder would need to have with both the exposure and the outcome, above and beyond the measured covariates, to shift the 95% confident interval toinclude the null value.
d
The analytic sample size was n = 8,951 for the following outcomes: all-cause mortality, functional disabilities, and dementia.
eInsomnia was measured one of the submodules in 2016, resulting in substantially smaller sample size (n = 821).
bConsistent with prior findings from studies of purpose in life (a conceptual cousin of Ikigai), our study
showed that Ikigai is associated with a lower risk ofdeveloping functional disability and dementia.42,43
Although the precise mechanisms by which Ikigai
might influence health outcomes have not yet been elucidated, there are at least three potential explanations,some of which can be discussed in the context of ourfindings regarding outcomes in other domains. First,

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evidence from purpose in life studies suggests that people with a higher levels of purpose tend to perceive
stressors as less stressful and emotionally recover fromnegative events more quickly, i.e., they are more resilient in adversity.44,45 Ikigai may likewise affect healthby buffering the adverse impacts of stressors: this explanation is supported by the observed associations
between Ikigai and reduced psychological distress andimproved subjective wellbeing. Second, Ikigai may

9Articles

motivate some individuals to invest in health-promoting
behaviors: for instance, prior results showed an association between higher levels of purpose in life and greater
engagement in physical activity. We only found modest
evidence that Ikigai was associated with lower risk of asedentary lifestyle and insomnia, which is consistent
with prior studies.46 Future studies assessing healthbehavior outcomes more comprehensively are warranted. Lastly, Ikigai may enhance regulation of physiological systems associated with reduced risk ofdementia and physical functioning problems (e.g.,
reduced inflammatory markers) although evidence has
been mixed, and more research is needed.47
In contrast to prior purpose studies,48,49 we did not
find substantial evidence that Ikigai was associated withall-cause mortality in the whole sample. However, theconfidence interval for the estimate was wide (0.60,
1.19) and the point estimate (0.85) was in fact relatively
close to that obtained by meta-analyses of the purpose
mortality relationship.48 There was some evidence of
the association with lower mortality among men andindividuals from higher socioeconomic backgrounds inour sample. The differences may also be explained byconceptual distinctions between purpose in life and Ikigai. For example, prior research examining associations
between both purpose in life and Ikigai with HbA1c—arisk factor of all-cause mortality—observed that purposein life was strongly associated with lower HbA1c, while
Ikigai was not.18 Another possible explanation for thediscrepancy is the difference in the operationalization of
the exposure variables (continuous or tertiles/quartiles
purpose scores in previous research vs. our binary Ikigai
score).50 The weak evidence for all-cause mortality inthe whole sample was also inconsistent with findings
from other Ikigai studies,13−15,51 which observed associations between Ikigai and lower all-cause and cardiovascular mortality in Japan. The conflicting results may be
attributable to differences in (a) age of the analytic samples (40−79 vs. ≥ 65 in our study), (b) length of followup (7 years vs. 3 years in our study), and (c) confounding
adjustment—we additionally adjusted for pre-baseline
psychological and social wellbeing as potential confounders 9,11,13,14,16 and for prior levels of the outcomes.
However, differences in results should not be exaggerated as the confidence interval in the present study forthe mortality association was quite wide.
While we observed consistent trends across outcomes for the domains of psychological distress andsubjective wellbeing, results were more mixed in otherdomains. For example, in the social wellbeing domain,
Ikigai was associated with more frequent participation
in hobby clubs, but we observed weak or little evidenceof associations with other outcomes in the same
domain. Further, in the pro-social/altruistic behaviors
domain, Ikigai was associated with more frequent sharing of skills and experiences, but we observed little evidence of an association with the frequency of

10volunteering. This specificity in the Ikigai-wellbeing
associations within a domain indicates that Ikigai mightenhance only certain aspects of wellbeing in these
domains and not others; understanding why this is so
and the mechanisms of action would be an interesting
direction for future research. Alternatively, the heterogeneity within domains might be attributable to the differential availability of opportunities to engage in specificsocial activities. For instance, hobby clubs might bemore accessible than other forms of social participation(e.g., sports clubs) in local communities and, hence,
more sensitive to the salubrious effect of Ikigai, which
resulted in the somewhat stronger association between
Ikigai and hobby club participation.
The sub-group analyses provided two insights. First,
Ikigai may improve physical health and other domainsof wellbeing (e.g., psychological distress) among men
but not as substantially among women. A prior study
also found the association between Ikigai and lower allcause mortality was stronger among men.14 Although
the reasons for this gender difference remain unclear, it
is possibly explained by patriarchal values embedded inJapanese society. Studies from Japan have documented
that social participation was associated with improved
health more strongly in men than in women, possibly
because Japanese men tend to feel more rewarded byhaving social roles and Ikigai.36,37 Moreover, although
speculative, sources of Ikigai may differ by gender andcontribute to the effect heterogeneity. Future studies
need to incorporate information on kind of activities
from which people drive Ikigai. Second, Ikigai may
improve some physical health outcomes (e.g., all-cause
mortality) among those with high SES but less so for
those with low SES, which is consistent with prior evidence that individuals from lower socioeconomic backgrounds may benefit less, health-wise, from having apurpose in life.38 A potential reason is the socioeconomic heterogeneity in sources to attain Ikigai. For
example, among individuals who identify “daily exercise” as a source of Ikigai, the high SES individuals areable to spend longer time engaging in exercise compared to those with low SES and must rely on other Ikigai sources. High SES and low SES individuals may
also derive Ikigai from different activities that yield collateral health benefits, which is another reason why weneed more detailed assessment of the kinds of activities
associated with Ikigai.
When evaluating potential antecedents of Ikigai, we
found some evidence of bidirectionality in the association between Ikigai and subsequent health and wellbeing. For example, Ikigai was associated with decreased
depressive symptoms; at the same time, lower depressive symptoms before the baseline were associated withan increased likelihood of having Ikigai later. The same
trend was observed for hopelessness. However, none ofthe other pre-baseline levels of the outcomes werestrongly predictive of subsequent Ikigai. Prior studies of

www.thelancet.com Vol 21 Month April, 2022

Articles

younger populations identified some predictors (e.g.,other aspects of subjective wellbeing) of subsequentchanges in purpose in life.6,52,53 Early randomized controlled trials, ranging from group cognitive behavioral
therapy to volunteering, have explored whether a senseof purpose can potentially be altered, but further work
is needed on developing Ikigai interventions.3,54−57
The strengths of our study include: (1) the first use ofan outcome-wide design to holistically evaluate associations between Ikigai with subsequent health and wellbeing, (2) the use of a large, nationwide, and longitudinalcohort study which helped ensure temporal ordering
between the covariates, Ikigai, and the outcomes, and(3) a rich adjustment of potential confounders including
prior outcome values to address reverse causation.
Nonetheless, our study has at least nine limitations.
First, our Ikigai measure was a single binary item that
asked if respondents had Ikigai or not. Sone et alassessed whether participants had Ikigai by asking “Do
you have Ikigai in your life?” with three response
options (yes/uncertain/no). In their analytic sample(n = 43,391), 36.4% indicated they were uncertain, suggesting our binary measure is prone to misclassification.13 Moreover, we could not assess varying levels of
Ikigai and its sources, which can result in heterogeneity
in the impacts of Ikigai on health and wellbeing. Futurestudies assessing varying levels of Ikigai are warranted
because such studies will inform whether increasinglevels of Ikigai among those who already have Ikigai
might provide additional benefit. Second, although Ikigai can be time-varying, we did not have information onwhen the respondents developed Ikigai and how long it
had persisted, making the interpretation of our findings
difficult. Future studies should adjust for pre-baseline
levels of Ikigai. Prior Ikigai levels were not available inour study, but such an adjustment would allow examining the impact of “changes” in Ikigai on health and wellbeing and also help further address potential
unmeasured confounding and reverse causation.20
Third, outcome measures we used in this study werelimited by data availability. Most outcomes were basedon self-report and crude, hence, susceptible to reporting
bias. For example, some people may obtain Ikigai fromengaging in unhealthy activities (e.g., smoking), andthe same individuals may underreport these outcomes.
Moreover, we could not assess some important outcomes that could be related to Ikigai (e.g., diet for thehealth behavior domain) as we lacked these information.58 Fourth, the 3-year follow-up period may havebeen too short for some of the beneficial effects of Ikigai
to manifest, which could explain the lack of conclusive
evidence for an association with all-cause mortality andother null findings in this study. Our ad-hoc analysis
indicated that changes from 2013 to 2016 were relatively
small for some outcomes; for example, only 6% of theanalytic sample (n=506) died during the three-year follow-up, and only 3% (n=162) experienced changes in

www.thelancet.com Vol 21 Month April, 2022

the binary self-reported health outcome (Table S9).
Fifth, the size of our analytic samples was relatively
smaller compared to the previous studies on Ikigai.13,14
The difference in sample size and corresponding power
may account for the inconclusive evidence in our study
concerning all-cause mortality, since our point estimate
was similar to many prior studies, but our confidence
interval was wider and included the null. Sixth, selection bias due to selective attrition is possible. The largest
sample attrition in this study occurred because the questionnaire containing the Ikigai item was distributed to arandomly selected 20% of the original sample(n=54,283 to n=10,867); hence, the attrition is random,and resulting selection bias is likely minimal. However,
attrition in other steps of the sample selection might
have caused selection bias, and we evaluated this possibility by comparing the distribution of covariates to
respondents of the pre-baseline wave survey and theanalytic sample; we observed similar distributions
between the two samples, which suggests reduced likelihood of selective sample selection (Table S8). Seventh,
we cannot entirely preclude the possibility of unmeasured confounding or reverse causation. We adjusted
for a comprehensive set of pre-baseline covariates,
including prior outcome levels (which tend to be thestrongest confounders and cause reverse causation).
However, even conditional on the pre-baseline outcome
values in 2010, outcome values may change before theexposure assessment in 2013 and independently confound the Ikigai-outcome associations. Moreover, we
conducted sensitivity analysis for unmeasured confounding and demonstrated some observed associations
might be somewhat robust to unmeasured confounding. Eighth, the outcome-wide approach sacrifices depth
for breadth, and this is indeed noted in the methodology
paper that presents the approach.21 However, the traditional design focusing on a single or a narrow set of outcomes has other limitations (e.g., not providing holistic
evidence on Ikigai-health associations, p-hacking, andpublication bias), which the outcome-wide design seeks
to address, at least to some extent. We think this is atrade-off, and the outcome-wide design (which contains
more breadth) and traditional study design (which contains more in-depth discussion) are both complementary and play different roles in the advancement ofscience. Lastly, these findings are based on a specificpopulation, and the results may not generalize to otherpopulations in which the potential effect modifiers of
the associations between Ikigai and health/wellbeing(e.g., reasons for having Ikigai) are distributed differently across populations.59
In conclusion, we found that having Ikigai may leadto decreased psychological distress and improved subjective wellbeing among Japanese older adults, as wellas improved physical health among Japanese older men
and those with high SES. More research is needed tounderstand the heterogeneous associations with the11Articles

outcomes within domains of social wellbeing and prosocial/altruistic behavior as well as the reasons why Ikigai
appeared less beneficial for some outcomes among
women and those with low SES.

Declaration of interests
Authors declare that they have no competing interests.

Acknowledgements
We are extremely grateful to all JAGES study participants for the use of their personal data, as well as toeveryone who participated and cooperated in the survey.

Contributors
S.S.O, K.S, I.K, T.J.V. contributed to the conceptualization. S.S.O, K.S contributed to the data curation, formal
analysis, methodology, project administration, visualization, validation, and writing original draft. T.J.V., E.S.K.,
I.K contributed to supervision. S.S.O, K.S, E.S.K, K.S,
N.K, T.F, K.K, T.L, C.TF, I.K, T.J.V. contributed to thewriting review and editing. K.K, K.S, T.J.V contributed
to funding acquisition. K.K, N.K, K.S contributed toinvestigation (data collection).

Data sharing statement
The dataset supporting the conclusions of this article isavailable in response to the request from the researchers
admitted by the JAGES committee (dataadmin.
ml@jages.net). All JAGES datasets have ethical or legal
restrictions for public deposition due to inclusion ofsensitive information from the human participants. Allanalyses were conducted in R, version 3.6.0. Code used
to generate the results presented in the manuscript areavailable from the corresponding author upon request.

Research project on health and welfare promotion
for the elderly from the Ministry of Health, Labour andWelfare, Health Labour Sciences Research Grants (KK,
H26-Choju-Ippan-006,
H27-Ninchisyou-Ippan-001
H28- Choju-Ippan-002, H28- Ninchisyou-Ippan-002,
H30-Kenki-Ippan-006,
H29-Chikyukibo-Ippan-001,
H30-Jyunkankinado-Ippan-004, 19FA1012, 19FA2001,
21FA1012).
The Research and Development Grants for Longevity
Science from Japan Agency for Medical Research anddevelopment(AMED)(KK,
JP18dk0110027,
JP18ls0110002,
JP18le0110009,
JP20dk0110034,
JP21lk0310073, JP21dk0110037).
The Research Funding for Longevity Sciences from
National Center for Geriatrics and Gerontology (KK, 2417, 24-23, 29-42, 30-30, 30-22, 20-19, 21-20).
Open Innovation Platform with Enterprises,
Research
InstituteandAcademia(OPERA,JPMJOP1831) from the Japan Science and Technology(JST).
The Japan Foundation For Aging And Health(J09KF00804).
Grant from Innovative Research Program on Suicide
Countermeasures (1-4).
Grant from Sasakawa Sports Foundation.
Grant from Japan Health Promotion & Fitness
Foundation.
Grant from Chiba Foundation for Health Promotion& Disease Prevention.
The 8020 Research Grant for fiscal 2019 from the8020 Promotion Foundation (adopted number: 19-206).
Grant from Niimi University (1915010).
The Wellbeing for Planet Earth Foundation [KS].
The Lee Kum Sheung Center for Health and Happiness [CTF].

Supplementary materials
Funding
US National Institutes of Health (TV, R01 CA222147).
The John Templeton Foundation grant (TV, 61075).
The Japan Society for the Promotion of Science (KK,
KS, KN, 15H01972, 15H04781, 15H05059, 15K03417,
15K03982, 15K16181, 15K17232, 15K18174, 15K19241,
15K21266,
15KT0007,
15KT0097,
16KK0059,
16H05556,
16K09122,
16K00913,
16K02025,
16K12964, 16K13443, 16K16295, 16K16595, 16K16633,
16K17256, 16K17281, 16K19247, 16K19267, 16K21461,
16K21465, 16KT0014, 17K04305, 17K04306, 25253052,
25713027, 26285138, 26460828, 26780328, 18H03018,
18H04071,
18H03047,
18H00953,
18H00955,
18KK0057,
19H03901,
19H03915,
19H03860,
19K04785, 19K10641, 19K11657, 19K19818, 19K19455,
19K24060, 19K20909, 20H00557).

12

Supplementary material associated with this article canbe found in the online version at doi:10.1016/j.
lanwpc.2022.100391.
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