Workshop	
  on	
  the	
  occasion	
  of	
  Dr.	
  Mar-n	
  Tondel	
  visi-ng	
  Osaka	On	
  the	  descrip-on	
  about	
  childhood	
  thyroid	
  cancer	  in	
  UNSCEAR	  White	  Paper	
  2016	
  	
Tomoya	  Yamauchi	  Graduate	
  School	
  of	
  Mari-me	
  Sciences,	
  Kobe	  Univreisty	
  

21st	
  April	  	
  2019	  Shin-­‐Osaka	
  Maru-­‐biru	
  Bekkan,	  5-­‐3	

1/20	

On	
  the	  descrip-on	
  of	
  childhood	
  thyroid	
  Cancer	
  in	
  UNSCEAR	
  White	  Paper	
  2016	  	

2/20	

Focusing	
  on	
  two	  paragraphs	
  of	
  111	  &	
  112	  in	
  UNSEAR	
  2016	
  White	  Paper,	
  we	
  examine	  by	
  what	  way	  they	  deny	  the	
  analy-cal	
  result	  of	
  the	
  excess	
  of	
  childhood	
  thyroid	
  cancer	  in	
  Fukushima	
  Prefecture	
  based	
  on	
  
the	
  conven-onal	
  epidemiology.	
  
	
  
As	
  the	
  report	
  style,	  these	  paragraph	
  is	
  completely	
  out	  of	
  usual	
  scien-ﬁc	
  manner.	
  
	
  
They	
  have	  never	  adequate	
  knowledge	
  about	
  epidemiology,	
  especially	
  on	
  the	
  role	  of	
  regional	
  classiﬁca-on	
  as	
  an	
  opera-on	
  variable,	
  an	
  importance	
  of	
  external	
  comparison	
  based	  on	
  ordinal	
  	
  incidence,	
  and	
  -me	
  interval	
  aZer	  the	
  exposure.	
  
	
  
The	
  main	
  paper	
  in	
  the	  present	
  discussion	
  is	
  that	  published	
  by	
  Tsuda	  et	
  al.	  in	
  Epidemiology	
  in	
  2016.	

round of screening included 298,577 examinees, and a second roundbegan in April 2014. We analyzed the prefecture results from the firstand second round up to December 31, 2014, in comparison with the
Epidemiology t 7PMVNF /VNCFS
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Thyroid Cancer
AmongPlant
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incidence andincidence withina reference
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3/20	
On	
  
the	
  annualdescrip-on	
  of	
  thechildhood	
  thyroid	  Cancer	  in	
  U
NSCEAR	
  
W
hite	
  
P
aper	
  
2
016
	
activeelements
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using
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ORIGINAL
ARTICLEokinobu, Eiji Yamamoto,and Etsuji
Suzukitime, 131I, 134Cs, and 137Cs, in addition to other radionuclides, wereyears, was observed in the central middle district of the prefecture comreleased to both the northwest and the south of the plant.1 The relapared with the Japanese annual incidence (incidence rate ratio = 50; 95%
confidence
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Epidemiology,
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Prevalenceof Thyroid
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cture com= 50; 95%
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active elements after the Great East Japan Earthquake andresult from radiation-exposed children based on a prelimiTsunami on March 11, 2011. As the wind shifted direction overnary dose assessment. When the World Health Organization
time, I, Cs, and Cs, in addition to other radionuclides, werereported a preliminary dose estimation in 2012, it estimatedreleased to both the northwest and the south of the plant. The relathe mean population dose for the more-affected locations
tive amounts of radioactive material released were estimated to bewithin Fukushima Prefecture (excluding areas less than 20 km
9.1% I, 17.5% Cs, and 38.5% Cs. Compared with Cherfrom the plant, which were immediately evacuated ), the lessnobyl where one reactor melted down, at Fukushima three reacaffected remainder of Fukushima Prefecture, neighboring
tors melted down. Radiation released into the atmosphere fromJapanese prefectures, the rest of Japan, neighboring countries,
the
Fukushimaaccidentwasestimatedtobeapproximately
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APrefecture,map
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Ibaragi
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However, Nagataki et al. reported that thyroid radia131
137
131
137
Tsushima-naka,
Kita-ku,Okayama,
700-8530,
Japan.
E-mail:tsudatos@
petabecquerel(I:
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Editors’Note:
A commentary
this article appears on page 323.
areas
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Figure.
petabecquerel ( I: 500 petabecquerel,Cs:(282,
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1.9(0.84,
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Editors’ Note:md.okayama-u.ac.jp.
Letters to the Editor regarding this article
can be found on the131
information Nuclearon
I fromthe Fukushima
ation areas were estimated to be 10 mSv in 95.7% of children
131
The Nuclear
radiologic equivalence
toExposure
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World
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estimatedtheintake41)
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becauseof the8-day half-lifeof(maximum:35 mSv) among 1,083
by screening
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(95,
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Scale
was reserved.
approximatelyof uncertain
the 5,200
petabecquerel
epidem/pages/default.aspx
Copyright © 2015 Wolters Kluwer Health, Inc. All
rightsThisone-sixth
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the destruction of monitoring sites
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HealthOrganitical Sciences,
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Japan; and Department
asdeliveredbyinhalation,
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Science,FacultyofInformatics,
Okayama
University
of
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work
cannotbechanged
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way
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IRRs were based on diagnosis by cytology. When basedon histologicallyconfirmed
cases
thatInc.were
operated
external comparisonsusing a latent
nary
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the
World
HealthOrganization©
2015 Wolters
Kluwer
Health,All rights
reserved. on, the IRRs for 4
www.epidem.com| 317duration ofzationScience,predicted
Okayama, Japan. that an excess of thyroid cancer cases would
andarea,ingestion.
areas
1044-3983/16/2703-0316
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yearsISSN:
were
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30 estimation(95% CI =ground39)itinshine,
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and 16 (95%InCIthe= 10,most24) in contaminatedthe least contaminatedarea
reported
preliminary
in22,
2012,
estimatedearlier aspectsof thisCI
researchat conferencesof theInternational
resultfromradiation-exposed
basedon
apopulation
prelimiety for
Environmental
Epidemiology
in Basel (2013)
andchildren
Seattle (2014).
for whichthe 10.1097/EDE.0000000000000385
secondary
examinationof cytology
positivecases
incomplete.
just outside
20 km from the plant, the proportion of exposure by
DOI:
the ismeandose for the more-affected
locations
Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.
The authors report no conflicts of interest.
4,5
within Fukushima Prefecture (excluding
areas less than 20 km
nary Supplemental
dose assessment.
When
the URL
World
digital content is available
through direct
citationsHealth Organizationfrom the plant, which were immediately evacuated4), the lessin the HTML and PDF versions of this article (www.epidem.com).
316
www.epidem.com
Epidemiology t 7PMVNF /VNCFS .BZ
reporteda |preliminary
estimationin 2012,estimated
This
content
is notpeer-reviewed ordose
copy-edited;
it is the sole responaffecteditremainderof Fukushima Prefecture, neighboring
sibility of the authors.
Japanese
prefectures,
the
rest
of
Japan,
neighboring
countries,
middle
area,
and
16
(95%
CI
=
10,
24)
in
the
least
contamiDISCUSSION
themean Toshihide
population
dose
for Ecology,
the Graduate
more-affected locations4
Correspondence:
Tsuda, Departmentof Humanand the rest of the world. A map of the three variously exposed
School of Environmental and Life Science, Okayama University, 3-1-1
nated
area
for whichthe secondary
examinationofFukushima
cytologywithin
Fukushima
Prefecture(excluding
areasareas
less
than
20 kmPrefecture is shown inAlthough
precise measurements of both external andTsushima-naka,
Kita-ku,Okayama,
700-8530,
Japan.
E-mail: tsudatos@
withinFigure.
clogical changes in 131I radioactivity levels in fallout per day
the subject of this study, Watanobe et al.6 conducted a screening
tical
Sciences,
Okayama
Japan; andDepartment
sound thyroid
screeningon all residents
ages University,≤18 years. TheOkayama,
first(Epidemiology
2016;27:
316–322)
6
a
131
POR
IRR
Areas
Districts
(1)
to
(9)
per
(95%
(95%
in various(95%cities; inCI)
I radioactivity levelsin spinach,
cow’s CI)
exerciseCasesfrom 2012 to
201310includingthyroidCI)
ultrasonography forround ofand
screening
included
298,577
examinees,andasecondroundof Information Science, Faculty of Informatics, Okayama Universityof
4,5milk, and chicken eggs; and in tap water pollution with 131I
1,137 Fukushima residents ages 18 years and younger at the time
began in April
2014.
We
analyzed
theprefecture
results
from
the
first
from March to May of 2011 in various areas of east Japan.
Science,Okayama,
Japan.
of the accident. No thyroid cancer was detected in this screening.
131 round
134up to December
137 31, 2014,
and secondin comparison with theThey
not consider
inhalaIn regionsof Japanother(201,than Fukushima,
the Japanese MinisNearest
area (1)(2011aspects
fiscal year)359592)radio1.5 did(0.63,
4.0)radioiodine exposure through30 (17,49)
Presented
earlierof
thisresearchatconferencesoftheInternational
SociheFukushima
DaiichiNuclearPower
Plantreleasedtion. They also measured radioiodine concentrations in breast
Japanese annual incidence and the incidence within a reference area
try of Environment conducted thyroid screening of 4,365 chil1
etyfor Environmental
andelements
Seattleafter(2014).
milk
119 volunteer
activethe and
Great
East
Japan
Earthquakedren
adolescentsages(304,
3–18
years
living inand
three prefectures
Middlearea(2012fiscal year) Epidemiology in Basel (2013)
402
522)
1.7from(0.81,
4.1) lactating women residing
33 within(25, 250
43)
in Fukushima
Prefecture.
(Aomori,Nagasaki)using ultrasoundauthors
reportrate
noratio,conflicts
of interest.
Tsunami on March 11, 2011.
AsYamanashi,
the windand
shifteddirectionover in the 2012 km of the Fukushima nuclear power plant between April 24
Results:The
The highest
incidenceusing a latency
period of 4
and31, 2011.
Seven of 23 women who 20
were(10,examinedcase
was detected.8 We summafiscal year7; one thyroid
North middle
district (2)digital
(123,
414)
1.0May(0.40,
2.7)
35)
134
137
time, 131I,directCs, andCs,
in addition to237
othercancer
radionuclides,
wereyears, was observedin the central middle
districtcontent
of the prefecturecom- throughSupplemental
is available
URL
citationsin April secreted a detectable level of 131I in their breast milk.
rize previously collected data on thyroid
screening including that
131
137
134
4
1
both the northwest
and theinsouthof(302,theplant.
The relaNational
Institute of Radiological50
Sciencesparedwith the middle
Japaneseannualincidence(incidence
ratio = 50;of
95%this released
Centraldistrict(3)and605
1,082)
2.6 The(0.99,
7.0)(25,esti90)
in theHTML
PDFrateversions
article to(www.epidem.com).
in Chernobyl
theeTable1 (http://links.lww.com/EDE/A968).
doses in mothers and infants from the data
confidence intervalThis[CI] =content
25, 90). The
prevalenceof thyroid cancer
wasThree years
and 10monthsafter theto
accident,
tive amounts
oftheradioactive
material
releasedwereestimatedbe the main mated equivalentisnotpeer-reviewed
orcopy-edited;
it
is
sole
respon12,13
14
of
Unno
et al., 4.9)
based on an acute ingestion39
model.
City district
462Compared
(299,
683)
2.0
(0.87,(25,These57)
134 study
objectiveof thiswasto establish
605Koriyama
per million examinees(95% CI(4)= 302, 1,082) and the prevalence
9.1% 131I, 17.5% 137Cs, and
38.5%
Cs.
withaccurate
Cher- and quantita- estimateddoses ranged from 119 to 432 mSv among mothers
sibility
the authors.
2oftive estimates from the Fukushima experience and to plan for
odds
ratio
comparedwiththereference
districtin
Fukushima
Prefecture
nobyl where one reactor melted
down, healthat Fukushima
three
reacand
330 to6.0)
1,190 mSv in their infants for thosetoSouth
middle districtToshihide
(5)
(210,
957)
2.1from(0.7,
40 living(17,4580)
the future public 486
needsof thepopulation.
Correspondence:
Tsuda,
Department
Human
Ecology, Graduate
was 2.6 (95%CI = 0.99, 7.0). In the second screening
round,
even under oftors
220
melted down.2 Radiation released into the atmosphere from4 km south or southwest, including Iwaki City in the Fuku-

T

15

131

PIDEMIOLOGY

131

a

b

131

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3

1

On	
  the	  descrip-on	
  of	
  childhood	
  thyroid	
  Cancer	
  in	
  UNSCEAR	
  White	  Paper	
  2016 	
Secretariat: Infinity Conference Group(Contact: Doreen Albertson)
1035 Sterling Road, Herndon, VA 20170
703-925-0178 (Voice) 703-925-9453 (Fax)
info@iseepi.org (E-Mail)
www.iseepi.org (website)
Francine Laden, Sc.D., President
Verónica Vieira, D.Sc., Secretary-Treasurer
Manolis Kogevinas, M.D., Ph.D., President-electThe following correspondence was sent on January 22, 2016, to authorities in Japan including
Ms Tomoko Kitajima, Director General, Environmental Health Department, Ministry of the Environment Governmentof Japan
Mr. Hiroyuki Kobayashi, Chief, Department of Health and Welfare, Section for Fukushima Health Management Survey
Ms Tamayo Marukawa, Minister of the Environment (ascertained), Ministry of the Environment Government of JapanOn behalf of environmental epidemiologist, we at the International Society for Environmental Epidemiology (ISEE),
the largest international professional organization for such scientists, are concerned about the recent scientificevidence suggesting an increase in the risk of thyroid cancer among residents of Fukushima that is much higher thanpreviously anticipated.
The recently published study1 demonstrates a 12‐fold higher risk of developing thyroid cancer among residents ofFukushima compared to the rest of the Japanese population. This is an exceptionally high risk, as pointed out in thecommentary to the published paper. This study builds on previous concerns about the lack of appropriate data andstudies to monitor the long‐term impact of the Fukushima nuclear disaster on local residents. Preliminary results ofthe study were presented at a special Symposium, organized at the ISEE Annual Meeting in Sao Paolo in September
2015. The discussion at the Symposium demonstrated great scientific interest of the Society members in follow up of
health consequences of Fukushima accident.
The study illustrates the need of the on‐going, systematic screening of the population affected by the accident, enabling
early detection and treatment of the cases of thyroid cancer. Besides direct benefits to the affected population, suchprospective study has great value for building up global knowledge about risks of ionizing radiation.
We appeal to the government as the stakeholder serving the interest of the people, to develop a series of measures
to scientifically document and follow up the health of residents of Fukushima and to better understand and estimate
the risks from the accident that happened in 2011. We believe that detailed monitoring of population exposure to radiation
possibly remaining in the environment after the accident remains necessary both for scientific and preventive reasons.
Such studies would provide invaluable contribution to the global body of knowledge on health consequences ofnuclear accidents and ways for reduction such risks in affected populations.
ISEE would be available to assist and support activities where needed by utilizing the expertise of its members. We
would be interested to know if, and how, you would envision the involvement of ISEE as an independent international
professional organization.
We would appreciate hearing back about your perspective regarding our letter and your future plans regarding thisimportant matter.
Sincerely

Francine Laden PhD
President of ISEE
cc. World Health Organization
1
Tsuda T et al, Thyroid Cancer Detection by Ultrasound Among Residents Ages 18 Years and Younger in Fukushima,Japan: 2011 to 2014. Epidemiology
2015 DOI: 10.1097/EDE.0000000000000385

4/20	

Following	
  the	
  publica-on	
  of	
  Tsudas’	
  study,	  the	
  president	
  of	
  Interna-onal	
  Society	
  for	
  Environmental	
  Epidemiology	
  (ISEE)	
  has	
  
send	
  a	
  le_er	
  to	
  the	
  Director	
  of	
  the	
  Ministry	
  of	
  the	  Environment	
  Government	
  of	
  Japan,	
  and	
  Fukushima	
  Prefecture.	
  
	
  
It	
  said	  “The	  recently	
  published	
  study	  demonstrates	
  a	
  12-­‐fold	
  higher	
  risk	  of	
  developing	
  thyroid	
  cancer	
  among	  residents	
  of	
  Fukushima	
  compared	
  to	
  the	  rest	  of	
  the	  Japanese	
  popula-on.	
  This	
  is	
  an	
  
excep-onally	
  high	  risk,	  as	
  pointed	
  out	
  in	
  
the	
  commentary	
  to	
  the	
  published	
  paper”.	
  
	
  
It	
  also	  said	  “ISEE	
  would	
  be	
  available	
  to	
  assist	  and	
  support	
  ac-vi-es	
  where	  needed	  by	
  u-lizing	
  the	
  exper-se	
  of	
  its	
  members”.	
  	
  
	
  
Japanese	  Government	
  and	  Fukushima	
  Prefecture	
  have	  made	  no	
  response	  to	
  this.	

On	
  the	  descrip-on	
  of	
  childhood	
  thyroid	
  Cancer	
  in	
  UNSCEAR	
  White	  Paper	
  2016 	

5/20	

111.	
   One	   paper	
   [T17]	
   (and	
   a	
   subsequently	
   published	
   response	   to	  cri-cisms	
   [T16])	
   claimed	
   to	
   demonstrate	
   that	   there	
   had	   been	   a	
  radia-on-­‐induced	
  increase	  in	
  thyroid	
  cancer	
  incidence:	
  the	
  authors	
  reported	
  a	
  50-­‐fold	
  (95%	
  CI:	
  25,	  90)	
  excess	
  in	
  Fukushima	
  Prefecture.	
  However,	
   the	   study	
   design	
   and	   methods	
   were	   too	   suscep-ble	
   to	  bias	
   [J2]	
   to	
   warrant	
   this	   interpreta-on.	
   Tsuda	
   et	   al.	
   [T17]	
   did	   not	  adequately	
   account	
   for	   the	   impact	
   of	
   the	   sensi-ve	
   ultrasound	
  screening	
  of	
  the	
  thyroid	
  upon	
  the	
  observed	
  rate	  of	
  thyroid	
  cancer.	
  Their	  conclusions	
  were	  based	  on	
  a	
  comparison	
  of	
  the	
  rate	  of	
  thyroid	
  cancer	   among	   those	
   people	   screened	
   by	
   FHMS	
   with	
   the	   rates	
   found	  elsewhere	
   in	
   Japan	
   where	
   few	
   children	
   had	   undergone	   thyroid	
  screening.	
  	
FHMS:	  Fukushima	
  Health	
  Management	
  Survey	
[T17],	
  [T16]	
  [J2],	
  [H3],	
  [T6],	
  [A2],	
  [T5]	

On	
  the	  descrip-on	
  of	
  childhood	
  thyroid	
  Cancer	
  in	
  UNSCEAR	
  White	  Paper	
  2016 	

6/20	

111.	
   ・・・・ Studies	
   of	
   other	
   popula-ons	
   screened	
   in	
   childhood,	  par-cularly	
   those	
   who	
   underwent	
   ultrasound	
   screening	
   in	
   three	  unexposed	
   Japanese	
   prefectures	
   [H3],	
   as	
   well	
   as	
   other	   screening	
  studies	
   of	
   young	
   people	
   in	
   Japan	
   [T6],	
   found	
   baseline	
   rates	   of	  thyroid	
   cancer	
   in	
   the	   absence	
   of	
   radia-on	
   exposure	
   that	
   were	  similar	   to	
   the	   FHMS	
   rates.	
   Similarly,	
   the	   Republic	
   of	
   Korea	
  experienced	
  an	
  apparent	
  large	
  increase	  in	
  thyroid	
  cancer	
  rates	  once	  they	
   ins-tuted	
   universal	
   screening	
   [A2].	
   It	
   is	   also	
   likely	
   that	
   some	
   of	  the	
   cancers	
   detected	
   by	
   screening	
   may	   have	
   existed	
   before	
   the	  radia-on	
  exposure	
  [T5].	
  	[T17],	
  [T16]	
  [J2],	
  [H3],	
  [T6],	
  [A2],	
  [T5]	

On	
  the	  descrip-on	
  of	
  childhood	
  thyroid	
  Cancer	
  in	
  UNSCEAR	
  White	  Paper	
  2016 	

7/20	

112.	
   Wakeford	
   et	   al.	
   [W2]	
   carried	
   out	   an	
   analysis	
   of	
   the	   data	   in	
   the	  Tsuda	   et	   al.	
   paper	
   by	
   comparing	
   the	   thyroid	
   cancer	
   prevalence	
  among	
   children	
   studied	
   by	
   FHMS	
   who	   were	
   residing	
   in	
   locali-es	
  with	
  rela-vely	
  low,	
  medium,	
  and	
  high	  exposures	
  as	
  a	
  result	
  of	
  the	
  accident,	
   as	
   deﬁned	
   by	
   Tsuda	
   et	   al.	
   The	   analysis	
   by	
   Wakeford	
   et	   al.	
  did	
  not	
  show	
  any	
  dose–response	  trend.	
  In	
  fact,	  the	
  ra-o	  of	
  thyroid	
  cancer	   prevalence	
   between	
   the	   locali-es	
   with	
   the	   highest	
   and	  lowest	   exposures	
   was	   only	
   1.08	
   (95%	
   CI:	
   0.60,	
   1.96)	
   [W2].	
   Other	
  inconsistencies	
   between	
   Tsuda	
   et	   al.	
   and	   the	   substan-al	
   body	   of	  data	
   on	
   radia-on-­‐induced	
   thyroid	
   cancer	
   in	
   childhood	   include:	
   (a)	
  the	
   Tsuda	
   et	   al.	
   paper	
   reported	   excesses	
   within	
   1–2	
   years	
   aZer	  radia-on	
   exposure,	
   whereas	
   studies	
   aZer	   the	   Chernobyl	   accident	
  and	
   other	
   studies	
   with	   much	   larger	
   doses	
   to	
   the	   thyroid	
   did	   not	  show	
  excesses	
  within	
  3–4	
  years;	
  	
[W2]	

On	
  the	  descrip-on	
  of	
  childhood	
  thyroid	
  Cancer	
  in	
  UNSCEAR	
  White	  Paper	
  2016 	

8/20	

112.	
  ・・・ 	  (b)	  all	  the	
  thyroid	
  cancers	
  in	
  the	
  FHMS	  occurred	
  among	  those	
   6–18	
   years	
   old	   at	
   radia-on	
   exposure,	
   while	
   other	
   studies	
  show	
  the	
  greatest	
  incidence	
  of	
  thyroid	
  cancer	
  induc-on	
  was	
  among	  those	
   with	
   early	
   childhood	
   exposure	
   (before	
   age	   5);	
   and	   (c)	
   the	  measured	
  doses	
  to	
  the	
  thyroid	
  were	  much	  too	
  low	  to	
  be	
  consistent	
  with	
  the	
  high	  prevalence	  they	  reported	
  [T6,	
  W2].	
  Because	
  of	
  these	  weaknesses	
  and	  inconsistencies,	
  the	  Commi_ee	
  does	  not	  consider	
  that	
   the	   study	
   by	
   Tsuda	
   et	   al.	
   presents	
   a	
   serious	
   challenge	   to	
   the	  ﬁndings	
  of	
  the	  2013	
  report.	
  	[W2],	
  [T6]	
	The	
   occurrence	
   of	   a	   large	
   number	
   of	
   radia-on	
   induced	
   thyroid	
  cancers	
   in	
   Fukushima	
   Prefecture—such	
   as	
   occurred	
   aZer	   the	  Chernobyl	   accident—can	
   be	   discounted,	
   because	
   absorbed	
   doses	  to	
   the	   thyroid	
   aZer	   the	   FDNPS	
   accident	
   were	
   substan-ally	
   lower	  than	
  those	
  aZer	  the	
  Chernobyl	  accident.	
  UNSCEAR	
  2013	
  222	
[T17],	
  [T16]	
  [J2],	
  [H3],	
  [T6],	
  [A2],	
  [T5].[W2]	

References	
  of	
  111	  &	
  112	  in	
  the	
  order	
  of	
  appearance	
  	

9/20	

[T17]	
  Tsuda,	  T.,	  A.	
  Tokinobu,	
  E.	
  Yamamoto	
  et	
  al.	
  Thyroid	
  cancer	
  detec-on	
  by	
  ultrasound	
  among	  residents	
  ages	
  18	
  years	
  and	
  younger	
  in	
  Fukushima,	
  Japan:	
  2011	
  to	
  2014.	
  Epidemiology	
  27(3):	
  316-­‐322	
  (2016).	
  	
  [T16]	
  Tsuda,	  T.,	  A.	
  Tokinobu,	
  E.	
  Yamamoto	
  et	
  al.	
  Response	
  to	
  the	  Commentary	
  by	
  Professor	
  Davis	
  and	  the	
  Seven	
  Le_ers.	
  -­‐	  a	
  well-­‐known	
  fact	  should	
  be	
  disseminated	
  to	
  remedy	
  the	
  problems.	
  Epidemiology	
  27(3):	
  e21-­‐23	
  (2016).	
  	
  
[J2]	
  Jorgensen,	
  T.J.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e17	  (2016).	
  	
  
[H3]	
  Hayashida,	
  N.,	  M.	
  Imaizumi,	
  H.	
  Shimura	
  et	
  al.	
  Thyroid	
  ultrasound	
  ﬁndings	
  in	
  children	  from	
  three	  Japanese	
  prefectures:	
  Aomori,	
  Yamanashi	
  and	  Nagasaki.	
  PLoS	  One	
  8(12):	
  e83220	
  (2013). 	
  Survey	
  of	
  childhood	
  thyroid	
  cancer	  in	
  Aomori,	
  Yamanashi	
  and	  Nagasaki	
  prefectures	
  	
  
[T6]	
  Takamura,	
  N.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e18	  (2016).	
  [A2]	
  Ahn,	
  H.S.,	
  H.J.	
  Kim	
  and	
  H.G.	
  Welch.	
  Korea's	
  thyroid-­‐cancer	
  “epidemic”-­‐-­‐	
  screening	
  and	
  overdiagnosis.	
  N	
  Engl	  J	
  Med	
  371(19):	
  1765-­‐1767	
  (2014).	
  The	  New	  England	
  Journal	
  of	
  Medicine	
  
	
  
	
  
	
  Screening	
  and	
  over-­‐diagnosis	
  in	
  Korea	  for	
  adults	
  [T5]	
  Takahashi,	
  H.,	  T.	
  Ohira,	
  S.	
  Yasumura	
  et	
  al.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e21	  (2016).	
  	
  
[W2]	
  Wakeford,	
  R.,	  A.	
  Auvinen,	
  R.N.	
  Gent	  et	
  al.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e20-­‐21	
  (2016).	
  	
  References	
  of	
  111	  &	
  112	  in	
  the	
  order	
  of	
  appearance	
  in	
  the	
  text	  	Epidemiology	
  has	
  opportunity	
  for	  open	
  discussions	
  prior	  to	
  the	
  ﬁnal	  publica-on,	
  using	
  le+ers	
  to	
  editor.	

Epidemiology t 7PMVNF /VNCFS .BZ

graph further highlights that grouping a
number of clearly “different” inequality measurements under a common
title “relative inequality measures” isunhelpful for those trying to understandtheir implicit value judgments. The usefulness of the OR as an inequality measure depends on how easy it is for policy
makers to understand its implicit value
judgments and how closely its inequality equivalence criterion matches public
perspectives of what changes in healthwould leave inequalities unchanged.
Given that the inequality equivalencecriterion of the OR is a mixture of theattainment-relative and shortfall-relative measures, it may not add muchto the picture but instead overcomplicate things. This is an issue for further
research.

[J2]	
  	

Gustav Kjellsson
Department of Economics
University of Gothenburg
Centre for Health Economics at the
University of Gothenburg (CHEGU)
Gothenburg, Sweden
gustav.kjellsson@economics.gu.se

Ulf-G Gerdtham
Department of Economics
Health Economics & Management
Institute of Economic Research
Lund University
Lund, Sweden
Center for Primary Health Care Research
Lund University/Region Skåne
Lund, Sweden

Dennis Petrie
Centre for Health Policy
School of Population and
Global Health
The University of Melbourne
Melbourne, VIC, Australia

REFERENCES
1. Kjellsson G, Gerdtham UG, Petrie D. Lies,
damned lies, and health inequality measurements: understanding the value judgments.
Epidemiology. 2015;26:673–680.
2. Popham F. Re: Lies, damned lies, and healthinequality
measurements:
understanding the value judgments. Epidemiology.
2016;27:e14–e15.
3. Wagstaff A. The bounds of the concentrationindex when the variable of interest is binary,with an application to immunization inequality. Health Econ. 2005;14:429–432.
4. Kjellsson G, Gerdtham U-G. Research on
Economic Inequality. Vol 21. Bingley, England:

Emerald Group Publishing; 2013. Lost intranslation: rethinking the inequality equivalence criteria for bounded health variables.
pp. 3–32. Available at: http://www.emeraldinsight.
com/10.1108/S1049-2585(2013)0000021002.
Accessed September 5, 2015.

3F5IZSPJE$BODFS"NPOH:PVOH1FPQMF
JO'VLVTIJNB
To the Editor:
read with interest the article by Tsudaet al.1 Nevertheless, I was very disappointed that it failed to identify itself as aclassic ecologic study and acknowledge
that its findings were, therefore, vulnerable to the ecologic fallacy. Likewise,
the accompanying commentary, by Scott
Davis, failed to point out the ecologic
study design.2
The flawed inferential logic,
known as ecologic fallacy, threatens allstudies that draw risk inferences basedon community incidence rates without
individual dose data, yet that is but oneof problems with ecologic studies.3
Despite the well-known limitationsof this study design, a bibliometric
review of ecological studies publishedin major epidemiologic journals foundthat only 69% of articles clearly specified their study’s design by mentioning
the word “ecological” or “ecologic,”
and 49% failed to acknowledge susceptibility to ecologic fallacy as amajor weakness.4
The reluctance of authors to label
their studies as ecologic is understandable given the negative reception suchstudies often receive. But the Tsuda
article goes beyond failing to acknowledge that it is ecologic. It actuallyhides its design by using “the residential address of the subjects in March
2011…as a surrogate for individual[dose],” and then reports measuresI

The author reports no conflicts of interest.
Copyright © 2016 Wolters Kluwer Health, Inc. All
rights reserved.
ISSN: 1044-3983/16/2703-0e17
DOI: 10.1097/EDE.0000000000000465© 2016 Wolters Kluwer Health, Inc. All rights reserved.

Lettersof association with odds ratios andrelative rates—risk metrics typically
employed in case–control and cohort
studies, respectively. These two alternative study designs are much morereliable because they are based on individual dose data and, therefore, notprone to be influenced by factors thatvary between communities.
The thyroid cancer rates in the
Tsuda study are not consistent withthe risks found in earlier cohort andcase–control studies and, therefore,
do not seem to be credible based on
our prior experience with radioactive
iodine. This should be bluntly statedbecause the media do not appreciatethat all study designs are not equallyvalid, and the public needlessly panics over studies of limited scientificvalue.
I must, therefore, concur with
Dr. Davis that “these findings do not
add anything new regarding radiationinduced thyroid cancer.” But I would further add that publishing studies that use
ecologic study designs without acknowledging the issue of ecologic fallacy is adisservice to the people of Fukushima,
who have already suffered greatly anddo not need the added burden of groundless worry about their risk of thyroid
cancer—a risk level that most epidemiologists would consider very small, notwithstanding the Tsuda study.
Timothy J. Jorgensen
Health Physics and Radiation
Protection Program
Department of Radiation Medicine
Georgetown University Medical Center
Washington, DC
tjorge01@georgetown.edu

REFERENCES
1. Tsuda T, Tokinobu A, Yamamoto E, Suzuki
E. Thyroid cancer detection by ultrasound among residents ages 18 years andyounger in Fukushima, Japan: 2011 to 2014.
Epidemiology. 2016;27:316–322.
2. Davis S. Screening for thyroid cancer after the
Fukushima disaster: what do we learn from suchan effort? Epidemiology. 2016;27:323–325.
3. Morgenstern H. Ecologic studies in epidemiology: concepts, principles, and methods. Annu
Rev Public Health. 1995;16:61–81.
4. Dufault B, Klar N. The quality of moderncross-sectional ecologic studies: a bibliometric
review. Am J Epidemiol. 2011;174:1101–1107.

XXXFQJEFNDPN ] e17

Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.

10/20	
Epidemiology t 7PMVNF /VNCFS .BZ

Letters

Disease Control and Prevention” therein.
This source is for policy making, not forscientific research. The author states“However, the National Academy of Sciences has reported that childhood cancers
have a period of 1 to 10 years. Therefore,
based on the best available scientific evidence and the following methodology
presented in this revised White Paperon Minimum Latency and Types or Categories of Cancer, the administrator
selected a minimum latency of 1 year for
use in the evaluation of cases of childhood cancer for certification in the WTCHealth Program.…”
I would be happy if the present letter might help readers correctly understand the results presented in the lastcolumn of Table 2.
Yoshisada Shibata
Nagasaki University
Nagasaki, Japan
rsr75103@nifty.com

REFERENCES
1. Tsuda T, Tokinobu A, Yamamoto E, Suzuki
E. Thyroid cancer detection by ultrasoundamong residents ages 18 years and younger in Fukushima, Japan: 2011 to 2014.
Epidemiology. 2016;27:316–322.
2. Rothman
KJ.
ModernEpidemiology:
An Introduction. New York, NY: Oxford
University Press; 2002.
3. Tsuda T. On the results of the thyroid screening carried out by Fukushima Prefecture. In:
Executive Committee of “Meeting of Nationwide
Pediatricians,” ed. Nationwide Pediatricians
Shall Protect Children from Radiation
Exposure from the Scientific Viewpoint. Osaka,
Japan: Executive Committee of “Meeting of
Nationwide Pediatricians”; 2013:27–40 (inJapanese).
4. Greenland S, Rothman KJ. Measures of occurrence. In: Rothman KJ, Greenland S,
Lash TL, eds. Modern Epidemiology, 3rded. Philadelphia, PA: Lippincott Williams &Wilkins; 2008:47–48.

-FUUFSTTo the Editor:
suda et al.1 reported the current findings of a large-scale thyroid disease
screening program in Fukushima Prefecture, Japan, following the release ofradionuclides, in particular iodine-131,
from the accident at Fukushima Dai-ichi
nuclear power station in March 2011.
They suggest that these findings indicate
an increase in cases of thyroid cancer
that is attributable to the accident. We

Te20 ] XXXFQJEFNDPN

were members of an International Expert
Working Group established by the World
Health Organization to perform an initialassessment of the health consequencesof the Fukushima Dai-ichi accident,2 andwe have serious concerns over this interpretation of Tsuda et al.1
Thyroid disease screening withultrasound can have a dramatic effecton the detection of thyroid nodules.
A 15-fold increase in the incidence of
thyroid cancer occurred in South Korea
after the introduction of a national cancer screening program in 1999, with
the incidence rate in regions increasing
in direct proportion to the percentage
of screened people.3 Consequently, it isinappropriate to compare the data fromthe Fukushima screening program withcancer registry data from the rest ofJapan where there is, in general, no suchlarge-scale screening. The proper comparison is between different screened
areas within Fukushima Prefecture,since significant radioactive contamination from the accident was confined toa relatively small part of the prefecture.
There is no statistically discernible difference in thyroid cancer prevalence between the low, intermediate, andhigh contamination areas of Fukushima
Prefecture. The prevalence ratio for thehighest to lowest contamination areas
was 1.08 (95% confidence interval [CI]:0.60, 1.96), and the highest prevalence
was seen in the area with an intermediatelevel of contamination (prevalence ratio= 1.21 [95% CI: 0.80, 1.82]). Furthermore, the measured levels of radioactivity in thyroids in Fukushima Prefecture
were far lower4 than would be needed toelevate cancer rates as much as Tsuda etal.1 claim.
The situation in areas of the former USSR heavily contaminated following the Chernobyl accident in 1986 isof relevance here: in these areas, many
children received high thyroid doses(much higher than those following the
Fukushima accident) and there is a clear
and large excess of thyroid cancer in thisgroup. The thyroids of 13,127 Ukrainians, 17 years old or younger at the timeof the accident, were screened between
1998 and 2000.5 Based on this study, 105(95% CI: 30, 258) background cases ofthyroid cancer would be expected fromthe first screening in Fukushima prefecture.6 The good agreement between thispoint estimate and the number of 112
cases that has been detected up to theend of March 2015 in Fukushima Prefecture1 does not permit the inference thatan effect of radiation exposure has been
demonstrated. A more plausible conclusion is that the screening program is
finding an anticipated increase in thyroid
cancer detection across the prefecture.

[W2]	
  	

Richard Wakeford

The University of Manchester
Manchester, United Kingdom
Centre for Occupational andEnvironmental HealthInstitute of Population HealthFaculty of Medical and Human Sciences
The University of Manchester
Manchester, United Kingdom
richard.wakeford@manchester.ac.uk

Anssi Auvinen
University of Tampere
Tampere, Finland

R. Nick Gent
Public Health England
Chilton, United Kingdom

Drs. Wakeford and Kesminiene have received
research funding from the European Commission. Dr. Wakeford has received a grant fromChildren with Cancer UK (current) and is a
Member of Technical Working Party of UK
Compensation Scheme for Radiation-linked
Diseases (current). He has served as consultant
to US Electric Power Research Institute (past),
Horizon Nuclear Power Ltd (past), and the UK
Treasury Solicitor (past).
Copyright © 2016 Wolters Kluwer Health, Inc. All
rights reserved.
ISSN: 1044-3983/16/2703-0e20
DOI: 10.1097/EDE.0000000000000466

Peter Jacob
Helmholtz Zentrum München
Munich, Germany

Ausrele Kesminiene
International Agency for Research on
CancerLyon, France

Dominique Laurier
Institute for Radiological Protection and
Nuclear Safety
Fontenay aux Roses, France© 2016 Wolters Kluwer Health, Inc. All rights reserved.

Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.

References	
  of	
  111	  &	
  112	  in	
  the	
  order	
  of	
  appearance	  	

11/20	

[T17]	
  Tsuda,	  T.,	  A.	
  Tokinobu,	
  E.	
  Yamamoto	
  et	
  al.	
  Thyroid	
  cancer	
  detec-on	
  by	
  ultrasound	
  among	  residents	
  ages	
  18	
  years	
  and	
  younger	
  in	
  Fukushima,	
  Japan:	
  2011	
  to	
  2014.	
  Epidemiology	
  27(3):	
  316-­‐322	
  (2016).	
  	
  
Main	
  Paper	
[T16]	
  Tsuda,	  T.,	  A.	
  Tokinobu,	
  E.	
  Yamamoto	
  et	
  al.	
  Response	
  to	
  the	  Commentary	
  by	
  Professor	
  Davis	
  and	  the	
  Seven	
  Le_ers.	
  -­‐	  a	
  well-­‐known	
  fact	  should	
  be	
  disseminated	
  to	
  remedy	
  the	
  problems.	
  Epidemiology	
  27(3):	
  e21-­‐23	
  (2016).	
  	
  Response	
[J2]	
  Jorgensen,	
  T.J.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e17	  (2016).	
  	
  cri-cal	
  Le_er	
[H3]	
  Hayashida,	
  N.,	  M.	
  Imaizumi,	
  H.	
  Shimura	
  et	
  al.	
  Thyroid	
  ultrasound	
  ﬁndings	
  in	
  children	  from	
  three	  Japanese	
  prefectures:	
  Aomori,	
  Yamanashi	
  and	  Nagasaki.	
  PLoS	  One	
  8(12):	
  e83220	
  (2013). 	
  Survey	
  of	
  childhood	
  thyroid	
  cancer	  in	
  Aomori,	
  Yamanashi	  and	
  oNf	
  agasaki	
  prefectures	  	
  Reference	
  Main	
  Paper	
[T6]	
  Takamura,	
  N.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e18	  (2016).	
  cri-cal	
  Le_er	
[A2]	
  Ahn,	
  H.S.,	
  H.J.	
  Kim	
  and	
  H.G.	
  Welch.	
  Korea's	
  thyroid-­‐cancer	
  “epidemic”-­‐-­‐	
  screening	
  and	
  overdiagnosis.	
  N	
  Engl	  J	
  Med	
  371(19):	
  1765-­‐1767	
  (2014).	
  The	  New	  England	
  Journal	
  of	
  Medicine	
  
	
  
	
  
	
  Screening	
  and	
  over-­‐diagnosis	
  in	
  Korea	  for	
  adults	
  Reference	  of	
  Le_er	  &	
  Response	
[T5]	
  Takahashi,	
  H.,	  T.	
  Ohira,	
  S.	
  Yasumura	
  et	
  al.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e21	  (2016).	
  	
  cri-cal	
  Le_er	
[W2]	
  Wakeford,	
  R.,	  A.	
  Auvinen,	
  R.N.	
  Gent	  et	
  al.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e20-­‐21	
  (2016).	
  	
  cri-cal	
  Le_er	References	
  of	
  111	  &	
  112	  in	
  the	
  order	  of	
  publica-on	  	

12/20	

[H3]	  PLoS	  One	
  8(12):	
  e83220	
  (2013).	
  	
  Reference	
  of	
  Main	  Paper		
  Survey	
  of	
  childhood	
  thyroid	
  cancer	  in	
  Aomori,	
  Yamanashi	
  and	  Nagasaki	
  prefectures	
  	
  
[A2]	
  N	
  Engl	  J	
  Med	
  371(19):	
  1765-­‐1767	
  (2014).	
  	
   Reference	  of	
  Le_er	  &	
  Response		
  Screening	
  and	
  over-­‐diagnosis	
  in	
  Korea	  for	
  adults	
  Main	
  Paper	
[T17]	  Epidemiology	
  27(3):	
  316-­‐322	
  (2016).	
  	
  

	
  
[J2]	
  Epidemiology	
  27(3):	
  e17	  (2016).	
  	
  
[T6]	
  Epidemiology	
  27(3):	
  e18	  (2016).	
  [W2]	
  Epidemiology	
  27(3):	
  e20-­‐21	
  (2016).	
  	
  
[T5]	
  Epidemiology	
  27(3):	
  e21	  (2016).	
  	
  
	
  
[T16]	  Epidemiology	
  27(3):	
  e21-­‐23	
  (2016).	
  	
  cri-cal	
  Le_er	Response	

UNSCEAR	
  wrote	
  2016	
  White	  Paper	  based	  on	
  the	
  Le_ers,	
  completely	
  ignoring	
  the	
  Response	
  by	
  the	
  authors.	
  UNSCEAR	  completely	
  failed	
  to	
  describe	
  the	  discussions	  in	  Epidemiology	
  as	
  an	
  academic	
  and	
  expert	
  journal.	
  	
  UNSCEAR	
  insulted	
  the	
  academic	
  ac-vity	
  in	
  Epidemiology.	

The	
  role	  of	
  regional	
  classiﬁca-on	
  as	
  an	
  opera-on	
  variable	

13/20	

111.	
   One	   paper	
   [T17]	
   (and	
   a	
   subsequently	
   published	
   response	   to	  cri-cisms	
   [T16])	
   claimed	
   to	
   demonstrate	
   that	   there	
   had	   been	   a	
  radia-on-­‐induced	
  increase	  in	
  thyroid	
  cancer	
  incidence:	
  the	
  authors	
  reported	
  a	
  50-­‐fold	
  (95%	
  CI:	
  25,	  90)	
  excess	
  in	
  Fukushima	
  Prefecture.	
  However,	
   the	   study	
   design	
   and	   methods	
   were	   too	   suscep-ble	
   to	  bias	
  [J2]	
  to	
  warrant	
  this	
  interpreta-on.	
The	
  study	  design	
  and	
  method	  was	  constructed	
  by	
  Fukushima	
  Medical	
  University,	
  FMU,	
  not	  by	
  the	
  authors	
  of	
  paper	
  [17].	
  
	
  
The	
  Le_er	  [J2]	
  insisted	
  the	
  study	
  is	
  an	
  “ecological	
  study”	
  but	
  FMU	  has	
  started	
  this	  as	
  a	
  “Cohort	
  study”.	
  
	
  
The	
  Le_er	  [J2]	
  claimed	
  that	  individual	
  dose	  have	  never	  measured,	
  but	
  this	  can	  not	  be	
  a_ributable	
  to	
  	
  the	
  authors	
  of	
  paper	
  [17].	
  The	
  role	  of	
  regional	
  classiﬁca-on	
  as	
  an	
  opera-on	
  variable	

14/20	

Since	  the	
  paper	
  [17]	
  is	
  u-lizing	
  the	
  regional	
  classiﬁca-on	
  as	
  an	
  
opera-on	
  variable	
  to	
  express	
  exposure	
  level,	
  it	
  is	
  adequate	  analysis	
  from	  the	
  view	
  point	
  of	
  Epidemiology.	
One	
  example	
  of	
  2x2	
  table,	  without	
  miss	  classiﬁca-on.	
  
It	
  is	
  assumed	
  that	  we	
  know	
  real	  exposure	
  level	  for	  individual.	
  	
exposed	non-­‐exposed	

Totals	Cases	

40	

10	

50	

Noncases	

60	

90	

150	

Totals	

100	

100	

200	

Odds	
  for	
  exposed	
  :	
  40/60	
  =	
  0.667	

Odds	
  for	
  non-­‐exposed	
  :	
  10/90	
  =	
  0.111	Odds	
  ra-o	  :	
  (40/60)/(10/90)	
  =	
  6.6	We	
  recognize	
  the	
  causal	
  rela-onship	
  between	
  the	
  exposure	
  and	  the	
  cases.	
  	

The	
  role	  of	
  regional	
  classiﬁca-on	
  as	
  an	
  opera-on	
  variable	

15/20	

The	
  regional	
  classiﬁca-on	
  is	
  never	  match	  with	  the	
  real	  classiﬁca-on.	
  Let’s	  consider	
  the	
  case	  when	
  20%	  of	
  exposed	
  to	
  be	
  treated	
  as	
  non-­‐
exposure.	
  (40	  -­‐>	
  32,	  60	  -­‐>48,	
  100	  -­‐>	
  80)	
exposed	non-­‐exposed	

Totals	Cases	

32	

18	

50	

Noncases	

48	

102	

150	

Totals	

80	

120	

200	

Odds	
  for	
  exposed	
  :	
  32/48	
  =	
  0.667	

Odds	
  for	
  non-­‐exposed	
  :	
  18/102	
  =	
  0.176	Odds	
  ra-o	  :	
  (32/48)/(18/102)	
  =	
  3.78	The	
  regional	
  classiﬁca-on	
  has	  a	
  bias	  to	
  close	  the	
  odds	  ra-o	  to	
  one	  (no	
  eﬀect).	
  When	
  one	
  ﬁnd	  an	
  eﬀect	
  using	  regional	
  classiﬁca-on,	
  it	
  is	
  enough.	
  	
  
The	
  paper	
  [T17]	
  found	  the	
  eﬀect,	
  applying	
  the	
  regional	
  classiﬁca-on.	
  UNSCEAR	
  do	
  not	  have	  enough	
  knowledge	
  on	
  Epidemiology.	
  	
  

An	
  importance	
  of	
  external	
  comparison	
  based	  on	
  ordinal	
  	
  incidence	

16/20	

111.	
   ・・・・ Studies	
   of	
   other	
   popula-ons	
   screened	
   in	
   childhood,	  par-cularly	
   those	
   who	
   underwent	
   ultrasound	
   screening	
   in	
   three	  unexposed	
   Japanese	
   prefectures	
   [H3],	
   as	
   well	
   as	
   other	   screening	
  studies	
   of	
   young	
   people	
   in	
   Japan	
   [T6],	
   found	
   baseline	
   rates	   of	  thyroid	
   cancer	
   in	
   the	   absence	
   of	
   radia-on	
   exposure	
   that	
   were	  similar	  to	
  the	
  FHMS	
  rates.	
  	In	  [H3]	
  one	
  case	  of	
  childhood	
  thyroid	
  cancer	
  was	
  found	
  from	  4,365	
  persons.	
  The	
  simple	
  ra-o	  par	
  1,000,000	
  persons	
  is	
  229.	
  UNSCEAR	
  insists	
  this	  ra-o	  	  is	
  comparable	
  to	
  that	  in	
  FHMS.	
  But	
  this	  kind	  of	
  discussion	
  lacks	
  sta-s-cal	
  considera-on.	
  In	
  Poisson	
  distribu-on,	
  lower	
  and	
  upper	  limits	
  of	
  95%	  conﬁdence	
  interval	
  of	
  count	
  1	
  are	
  0.025318	  and	
  5.57163,	
  respec-vely.	
  The	
  observa-on	
  in	
  [H3]	
  is	
  concordant	
  with	  the	
  ordinal	
  incidence	
  between	
  5.8	
  and	
  127.6	
  persons	
  par	
  1,000,000	
  persons.	
  Age	
  group	  in	
  [H3]	
  was	
  between	
  3	
  
and	
  18	
  years	
  old.	
  The	
  lower	  group	
  was	  not	
  involved,	
  diﬀerent	
  from	  FHMS.	  It	  is	
  diﬃcult	
  to	
  make	  any	
  scien-ﬁcally	
  meaningful	  discussions.	
  An	
  importance	
  of	
  external	
  comparison	
  based	  on	
  ordinal	
  	
  incidence	

17/20	

111. ・・・・ Studies	
   of	
   other	
   popula-ons	
   screened	
   in	
   childhood,	  par-cularly	
   those	
   who	
   underwent	
   ultrasound	
   screening	
   in	
   three	  unexposed	
   Japanese	
   prefectures	
   [H3],	
   as	
   well	
   as	
   other	   screening	
  studies	
   of	
   young	
   people	
   in	
   Japan	
   [T6],	
   found	
   baseline	
   rates	   of	  thyroid	
   cancer	
   in	
   the	   absence	
   of	
   radia-on	
   exposure	
   that	
   were	  similar	  to	
  the	
  FHMS	
  rates.	
  	
Le_er	
  [T6]	
  said	  three	
  cases	  of	
  thyroid	
  cancer	
  were	  found	
  from	  2,307	  new	
  comers	
  to	
  Okayama	
  University	
  in	
  2013.	
  Since	
  they	  were	  university	
  students,	
  the	
  age	
  group	
  is	
  diﬀerent	
  from	  that	  in	
  FHMS.	
  Response	
  [T16]	
  indicated	
  the	
  fact	  that	  no	
  addi-onal	
  cases	
  were	  found	
  between	  2012	
  and	  2015	
  from	  36,927	
  persons,	
  including	
  elder	  students.	
  UNSCEAR	
  ignored	
  this	  response	
  when	
  they	  prepare	
  the	  White	  Paper	  in	
  2016.	
  An	
  importance	
  of	
  -me	
  interval	
  aZer	  the	
  exposure	

18/20	

112.	
  Wakeford	
  et	
  al.	
  [W2]	
  carried	
  out	  an	
  analysis	
  of	
  the	
  data	  in	
  the	
  Tsuda	   et	   al.	
   paper	
   by	
   comparing	
   the	   thyroid	
   cancer	
   prevalence	
  among	
   children	
   studied	
   by	
   FHMS	
   who	   were	
   residing	
   in	
   locali-es	
  with	
   rela-vely	
   low,	
   medium,	
   and	   high	
   exposures	
   as	   a	   result	
   of	
   the	  accident,	
  as	
  deﬁned	
  by	  Tsuda	  et	
  al.	
  The	
  analysis	
  by	
  Wakeford	
  et	
  al.	  did	
  not	
  show	
  any	
  dose–response	  trend.	
  In	
  fact,	  the	
  ra-o	  of	
  thyroid	
  cancer	   prevalence	
   between	
   the	   locali-es	
   with	
   the	   highest	
   and	  Epidemiology t 7PMVNF /VNCFS .BZ
lowest	  exposures	
  was	
  only	  1.08	
  (95%	
  CI:	
  0.60,	
  1.96)	
  [W2].	
  	Letters700

To the Editor:oshihide Tsuda and his colleagues1
600
report that the annual incidence rate
500
of thyroid cancer observed from September 2011 to March 2014 among ca.
400
300,000 children in Fukushima ages
300
18 years or less as of March 2011 isapproximately 30-fold higher than the200
mean annual incidence rate in Japan
reported by the National Cancer Center
100of Japan. However, the formula they use
0in Table 2 for deriving the incidence rate
low
middlehighratio, in which the prevalence is approxiFIGURE. 1SFWBMFODFPGUIZSPJEDBODFSJOBSFBTPG'VLVTIJNB1SFGFDUVSFXJUIEJGGFSFOU mately equal to the product of “incidence
SBEJBUJPODPOUBNJOBUJPO
rate” and “latent duration of disease,”
has not been validated to date, although
Alfred	  Korblein.	
  Re:	
  Thyroid	
  cancer	
  among	
  young	
  people	  in	
  Fukushima.	
  Epidemiology	
  27(3):	
  e18-­‐e19	
  (2016).	
  	
they cite 2nd edition of Rothman2 probTo the Editor:
2007.2 In Korea, however, it is 18.3 ably for authorizing their formula.
Rothman2 presents two formulasn the recent article by Tsuda and col- among men and 87.4 among women in
Thyroid cancer prevalence per Mio

TLe_er	  [W2]	
  paid	  no	
  a_en-on	
  on	
  the	
  -me	  interval	
  aZer	  the	
  exposure,	
  nevertheless	
  they	
  spoken	
  about	  the	
  dose-­‐response	
  rela-on.	

3

4

Epidemiology t 7PMVNF /VNCFS .BZ

An	
  importance	
  of	
  -me	
  interval	
  aZer	  the	
  exposure	

point is about minimum
nference on minimum
solely based on the CenControl-World Trade Cenlso on the Chernobyl data
cess thyroid cancer cases
after the 1986 Chernobyl
he excess was mainly inn 1980s, in contradiction
nt, “many patients wereyears old.”4
we discuss the issue of
In contrast to the second
y analysis was performed
he latent duration in theween the date when thyme detectable by screenhan 5.1 mm in diameter)
en it could be diagnosed
duration assigned in ourrs,9 which may be long for
ypothesis tested. One canber of years, even 20, in
alysis and still observe thesses. The effect of preclinbe quantitatively estimatedd proportion of preclinical
he detected cancer cases
http://links.lww.com/EDE/

Response	
  [T16]	
  	

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Nearest area (1) (2011 fiscal year)
Middle area (2012 fiscal year)
North middle district (2)Central middle district (3)Koriyama City district (4)South middle district (5)Least contaminated area (2013 fiscal year)
Iwaki City district (6)Southeastern least contaminated district (7)Western least contaminated district (8)Northeastern least contaminated district (9)1stExaminees

CancerCases

POR (95% CI)a41,810139,338
50,61818,19454,063
16,463
119,328
49,42929,82033,720
6,359

15
56
12
11
25
8
42
24
7
11
0

4.6 (2.2, 11)
2.6 (1.2, 6.0)
1.5 (0.65, 3.9)
3.9 (1.6, 10)
3.0 (1.4, 7.2)
3.1 (1.2, 8.4)
2.1 (0.92, 5.2)
1 (reference)
1.4 (0.54, 3.8)
0 (0, 2.5)

1	
  year	2	
  years	

3	
  years	

a

We obtained these results by correcting the observed cancer cases. With regard to central middle district (3) andKoriyama city district (4), we show the means of corrected PORs and 95% CIs because we cannot use numbers with adecimal point in EpiInfo 7.
CI indicates confidence interval; POR, prevalence odds ratio.

Prevalence	  Ra-os	
  
are	
  the
highest	  in	
  Nearest	  area	
  ausingnd	
  alower	  in	
  of the lengthOofdds	
  time elapsed
betweencontaminatedareas in Ukraine”
14
accidentcontaminated	
  and timing of screening.
We linearexcess relative
Given
the	
  least	  districts.	
  Higher	  POR	
  riskis	
  fmodel.
ound	
  
in	
  Iwaki	  mentioned as the second limitation of our the substantially larger sample size, how9
City,	
  article,
where	  iodine	  plume	  had	
  directpassed	  away.	  waki	
  city	  is	
  not	
  thatradio	
  this potential
confounding
ever,
estimationfrom Iultrasoundleads to an underestimation.
As a sensiscreeningso	
  contaminated	
  by	
  radio	
  cesium.	
  	
 data among 47,203 examinees
tivity analysis, we assigned the time fromthe accident to screening in each area toin the unexposed or relatively low contaminated areas in Ukraine would be moreConclusion	

20/20	

Descrip-on	
  about	
  childhood	
  thyroid	
  cancer	
  in	
  UNSCEAR	
  2016	  white	
  paper	  （111&112）was	
  examined.	
  The	
  descrip-on	
  by	
  UNSCEAR	
  has	
  failed	
  to	
  correctly	
  reconstructed	
  the	
  scien-ﬁc	
  discussions	
  which	  were	  made	  in	
  the	
  academic	
  and	  expert	  journal	
  of	
  “Epidemiology”.	
  UNSCEAR	  have	  never	
  enough	
  knowledge	
  about	
  epidemiology,	  especially	
  on	
  the	
  role	  of	
  regional	
  classiﬁca-on	
  as	
  an	
  opera-on	
  variable,	
  an	
  importance	
  of	
  external	
  comparison	
  based	  on	
  ordinal	  	
  incidence,	
  and	
  -me	
  interval	
  aZer	  the	
  exposure	
  for	
  dose-­‐resopnse	  rela-on.	
  We	
  can	  not	
  accept	  the	  descrip-on	
  in	
  111	  &	
  112	  of	
  UNSCEAR2016	
  white	
  paper,	
  from	  the	
  view	
  points	
  of	
  sciences.	
  For	
  Japanese	
  reading	  persons	  本発表に関連する論考が『科学9月号』（岩波書店）に掲載されています。	
  以下のサイトから無料でダウンロードできます。	
  h_p://www.lib.kobe-­‐u.ac.jp/handle_kernel/90005240	
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