the nurses ' health study ii ( nhsii ) is an ongoing prospective study of u.s .
a total of 109,172 participants remained after exclusion for diagnosis of any type of diabetes , cancer , or cardiovascular disease at baseline ( 2% ) or for missing information on childhood body shape ( 2.5% ) , bmi at age 18 years ( 0.7% ) , or baseline bmi ( 0.3% ) .
this study was approved by the institutional review board of the partners health care system ( boston , ma ) . at baseline ,
body fatness at ages 5 , 10 , and 20 years of age was assessed by recall of somatotypes or 9-level pictorial diagrams developed by stunkard et al .
( 9 ) representing sizes ranging from extreme thinness ( category 1 ) to obesity ( category 9 ) .
the use of recalled somatotypes has been validated in both older ( 10 ) and younger ( 11 ) women by comparison with childhood records .
somatotypes at ages 5 , 10 , and 20 years correlated moderately with recorded bmi ( r = 0.60 , 0.65 , and 0.66 , respectively ) ( 10 ) .
the validity did not differ by adult bmi at the time of report ( 10 ) .
weight change was the difference between weight at age 18 years and weight at baseline in 1989 .
the correlation between recalled weight at age 18 and documented weight from college or nursing school records was 0.84 , and the correlation between self - reported and technician - measured adult weight was 0.96 ( 13 ) .
a supplementary questionnaire was mailed to confirm the self - report of diabetes diagnosis and to distinguish different types of diabetes ( 14 ) .
the national diabetes data group diagnostic criteria were used for cases reported through 1997 and required confirmation of at least one of the following : 1 ) one or more symptoms ( weight loss , hunger , thirst , or polyuria ) and elevated glucose ( fasting 7.8 mmol / l [ 140 mg / dl ] or random plasma or 2-h glucose 11.1
mmol / l [ 200 mg / dl ] ) , 2 ) no symptoms but occurrence of elevated plasma glucose as described above on at least two different occasions , or 3 ) use of insulin or oral hypoglycemic medication ( 15 ) . for cases occurring after 1998 ,
the cutoff of fasting plasma glucose was changed to 7.0 mmol / l ( 126 mg / dl ) in accordance with revised criteria ( 16 ) .
we excluded women classified as having only gestational diabetes mellitus or type 1 diabetes . in the nurses ' health study , the supplemental questionnaire was highly reliable regarding diabetes diagnosis ( 14 ) . in a random sample of 84 women classified as being a case subject , medical records were available for 62 of these women and an endocrinologist confirmed the diagnosis in 61 women ( 98% ) ( 14 ) .
age was calculated as months from the reported birth date to date of questionnaire return .
race , smoking status , birth weight , prematurity , multiple gestation birth , age of menarche , being breast - fed , alcohol consumption , and family history of diabetes were self - reported at baseline or in 1991 .
parity and age at first birth were measured biennially . physical activity , in met units ,
was derived from the average time spent in certain activities ( e.g. , jogging or running ) in 1989 , 1991 , 1997 , and 2001 .
differences in participant characteristics by childhood somatotype at age 10 years were compared using  or linear regression .
person - years were calculated based on date of return to date of diagnosis , death , or 1 july 2005 , whichever came first .
multivariate cox proportional hazard models were used to estimate the relative risk ( rr ) for the associations of somatotypes at ages 5 , 10 , and 20 years and bmi at age 18 years with type 2 diabetes risk .
we used category 2 as the reference because most women had reported this category at both ages 5 and 10 years .
in one multivariate model , estimates were adjusted for age ( continuous ) , race ( african american , hispanic , asian , or white ) , parity ( 0 , 12 , or 3 ) in combination with age at first birth ( > 24 years ) , family history of diabetes ( maternal , paternal , or both ) , smoking ( current , past , or never ) , and physical activity ( quintiles ) . in a second model among participants not missing birth weight information ( n = 87,349 , case subjects = 2,771 ) , estimates were adjusted for characteristics influencing childhood size including age , race , family history of diabetes , birth weight ( < 5.5 , 5.56.9 , 7.08.4 , 8.59.9 , or 10 pounds ) , prematurity or multiple gestation birth status of the woman ( yes or no ) , and age of menarche ( < 12 , 12 , 13 , 14 , or > 14 years ) . to test for significant trends ,
linear models were fitted using the median values of each category of exposure ( e.g. , 17.0 , 19.0 , 21.0 , 23.5 , 28.0 , and 35.0 for bmi at age 18 years ) .
the differences in somatotype categories ( between ages 5 and 10 and between ages 10 and 20 ) or in weight ( between age 18 years and baseline ) were used to assess whether change in size was associated with diabetes development .
models were additionally adjusted for starting size ( e.g. , adjustment for age 5 somatotype in evaluating the difference between ages 5 and 10 ) , because where a woman began in size may reflect weight gain or loss ( i.e. , heavier women have the possibility to lose more weight ) .
the cumulative effect of overweight across the life course before reported diabetes was evaluated using the combination of somatotype 5 at age 10 , bmi 25 kg / m at age 18 , and bmi 25 kg / m at baseline ( i.e. , to represent adulthood ) .
the reference group comprised women who reported no overweight at any of those time points .
analyses were performed using sas ( version 8.2 ; sas institute , cary , nc ) .
at baseline , body fatness at ages 5 , 10 , and 20 years of age was assessed by recall of somatotypes or 9-level pictorial diagrams developed by stunkard et al .
( 9 ) representing sizes ranging from extreme thinness ( category 1 ) to obesity ( category 9 ) .
the use of recalled somatotypes has been validated in both older ( 10 ) and younger ( 11 ) women by comparison with childhood records .
somatotypes at ages 5 , 10 , and 20 years correlated moderately with recorded bmi ( r = 0.60 , 0.65 , and 0.66 , respectively ) ( 10 ) .
the validity did not differ by adult bmi at the time of report ( 10 ) .
weight change was the difference between weight at age 18 years and weight at baseline in 1989 .
the correlation between recalled weight at age 18 and documented weight from college or nursing school records was 0.84 , and the correlation between self - reported and technician - measured adult weight was 0.96 ( 13 ) .
a supplementary questionnaire was mailed to confirm the self - report of diabetes diagnosis and to distinguish different types of diabetes ( 14 ) .
the national diabetes data group diagnostic criteria were used for cases reported through 1997 and required confirmation of at least one of the following : 1 ) one or more symptoms ( weight loss , hunger , thirst , or polyuria ) and elevated glucose ( fasting 7.8 mmol / l [ 140 mg / dl ] or random plasma or 2-h glucose 11.1
mmol / l [ 200 mg / dl ] ) , 2 ) no symptoms but occurrence of elevated plasma glucose as described above on at least two different occasions , or 3 ) use of insulin or oral hypoglycemic medication ( 15 ) . for cases occurring after 1998 ,
the cutoff of fasting plasma glucose was changed to 7.0 mmol / l ( 126 mg / dl ) in accordance with revised criteria ( 16 ) .
we excluded women classified as having only gestational diabetes mellitus or type 1 diabetes . in the nurses ' health study ,
the supplemental questionnaire was highly reliable regarding diabetes diagnosis ( 14 ) . in a random sample of 84 women classified as being a case subject , medical records were available for 62 of these women and an endocrinologist confirmed the diagnosis in 61 women ( 98% ) ( 14 ) .
age was calculated as months from the reported birth date to date of questionnaire return .
race , smoking status , birth weight , prematurity , multiple gestation birth , age of menarche , being breast - fed , alcohol consumption , and family history of diabetes were self - reported at baseline or in 1991 .
physical activity , in met units , was derived from the average time spent in certain activities ( e.g. , jogging or running ) in 1989 , 1991 , 1997 , and 2001 .
differences in participant characteristics by childhood somatotype at age 10 years were compared using  or linear regression .
person - years were calculated based on date of return to date of diagnosis , death , or 1 july 2005 , whichever came first .
multivariate cox proportional hazard models were used to estimate the relative risk ( rr ) for the associations of somatotypes at ages 5 , 10 , and 20 years and bmi at age 18 years with type 2 diabetes risk .
we used category 2 as the reference because most women had reported this category at both ages 5 and 10 years .
in one multivariate model , estimates were adjusted for age ( continuous ) , race ( african american , hispanic , asian , or white ) , parity ( 0 , 12 , or 3 ) in combination with age at first birth ( > 24 years ) , family history of diabetes ( maternal , paternal , or both ) , smoking ( current , past , or never ) , and physical activity ( quintiles ) . in a second model among participants not missing birth weight information ( n = 87,349
, case subjects = 2,771 ) , estimates were adjusted for characteristics influencing childhood size including age , race , family history of diabetes , birth weight ( < 5.5 , 5.56.9 , 7.08.4 , 8.59.9 , or 10 pounds ) , prematurity or multiple gestation birth status of the woman ( yes or no ) , and age of menarche ( < 12 , 12 , 13 , 14 , or > 14 years ) . to test for significant trends ,
linear models were fitted using the median values of each category of exposure ( e.g. , 17.0 , 19.0 , 21.0 , 23.5 , 28.0 , and 35.0 for bmi at age 18 years ) .
the differences in somatotype categories ( between ages 5 and 10 and between ages 10 and 20 ) or in weight ( between age 18 years and baseline ) were used to assess whether change in size was associated with diabetes development .
models were additionally adjusted for starting size ( e.g. , adjustment for age 5 somatotype in evaluating the difference between ages 5 and 10 ) , because where a woman began in size may reflect weight gain or loss ( i.e. , heavier women have the possibility to lose more weight ) .
the cumulative effect of overweight across the life course before reported diabetes was evaluated using the combination of somatotype 5 at age 10 , bmi 25 kg / m at age 18 , and bmi 25 kg / m at baseline ( i.e. , to represent adulthood ) .
the reference group comprised women who reported no overweight at any of those time points .
analyses were performed using sas ( version 8.2 ; sas institute , cary , nc ) .
there were 3,307 incident cases of type 2 diabetes over 16 years of follow - up , for an incidence rate of 197 cases per 100,000 person - years .
table 1 shows the characteristics for all women and by reported childhood somatotype at age 10 years categorized from 1 to 6 .
women with somatotype 1 at age 10 years were more likely to be of minority race , to have birth weight < 5.5 pounds , to have been born prematurely , and to have had a later age at menarche ; whereas women with somatotype 6 were more likely to have birth weight > 10 pounds , to actively smoke , to be nulliparous , and to have had a positive parental history of diabetes .
somatotypes at ages 5 , 10 , and 20 years were associated with each other . of the women reporting somatotype 6 at age 10 years , 41% reported somatotype 6 at age 5 years , and 28% at age 20 years .
weight and bmi were also positively associated with somatotype ; a 12 kg / m increase in adolescent or adult bmi was observed per increase in somatotype category .
baseline characteristics of nhsii participants by somatotype at age 10 years means  sd presented unless indicated .
n = 109,172 . * reported in 1991 questionnaire ( rather than at baseline in 1989 for all other covariates ) .
somatotypes at ages 5 , 10 , and 20 years and bmi at age 18 years ( table 2 ) were all significantly and positively associated with diabetes risk ( all ptrend < 0.0001 ) .
compared with having a somatotype of 2 , the rr of diabetes associated with a somatotype 6 at age 5 was 2.19 ( 95% ci 1.792.67 ) , at age 10 years was 2.57 ( 2.203.01 ) , and at age 20 years was 5.67 ( 4.926.54 ) .
the rr among women who reported a bmi at age 18 > 30 kg / m was 8.72 ( 7.5810.02 ) compared with women with a bmi of 1819 kg / m . among a subgroup not missing birth weight information ( n = 87,175 ) , adjustment for childhood factors including birth weight did not substantially change these estimates .
childhood and adolescent size and rr ( 95% ci ) of type 2 diabetes in adulthood in nhsii data are rr ( 95% ci ) unless otherwise indicated .
* model 2 adjusted for age , race , smoking status , parental history of diabetes , parity , age at first birth , and adult physical activity .
model 3 adjusted for age , race , parental history of diabetes , birth weight , multiple birth , prematurity , age of menarche ( n = 87,175 , case subjects = 2,681 in subgroup not missing birth weight information ) .
type 2 diabetes risk increased among women who reported increases in size whether by somatotype between ages 5 and 10 and between ages 10 and 20 or by weight gain since age 18 ( table 3 ) . compared with women reporting no change in somatotype , one or more unit increases in somatotype at these ages
were associated with approximately twice the risk , whereas decreases in somatotype at these ages were associated with reduced risk .
weight gain since age 18 , which is the difference between baseline weight and weight at age 18 , was also significantly associated with risk of diabetes . compared with women who had little change in weight ( i.e. , 4.9 pounds ) ,
even a weight gain of 58 pounds doubled risks , whereas weight gain of > 25 pounds increased risk by > 20 times .
weight loss was associated with increased risk until after adjustment for bmi at age 18 to account for greater weight loss being associated with larger adolescent body size . in analyses stratified by bmi at age 18 years , weight loss of 10 pounds was significantly associated with a reduced risk of diabetes among women who were overweight ( rr 0.45 [ 95% ci 0.220.91 ] ) or obese ( 0.45 [ 0.280.72 ] ) in adolescence but not among those who were lean ( 1.72 [ 0.763.90 ] ) .
changes in size and rr ( 95% ci ) of type 2 diabetes in nhsii data are rr ( 95% ci ) unless otherwise indicated .
n = 109,172 . * model 2 adjusted for age , race , smoking status , parental history of diabetes , parity , age at first birth , and adult physical activity .
model 2 variables with additional adjustment for earlier size , i.e. , somatotype at age 5 and 10 years and bmi at age 18 years .
the prevalences of overweight by somatotype 5 at ages 5 , 10 , and 20 years were 7 , 12 , and 11% , respectively .
most of the cases ( 83% ) in the cohort occurred among women who were overweight ( bmi 25 kg / m ) at baseline with an incidence rate of 562 per 100,000 person - years . among these women ,
the prevalences of overweight by somatotype 5 were 12 , 21 , and 23% , respectively . to evaluate the cumulative effect of being overweight across the life course ,
women were jointly categorized as being overweight using somatotype at age 10 , bmi at age 18 years , and bmi at baseline ( with mean age of 34 years ) ( fig .
women who were overweight only as an adult ( bmi > 25 kg / m ) had an adjusted rr of 8.23 ( 95% ci 7.419.15 ) compared with women who were never overweight at any age .
the adjusted rr increased to 15.10 ( 13.2117.26 ) for women who were also overweight at age 10 ( somatotype 5 ) and age 18 ( bmi > 25 kg / m ) .
however , women who were overweight at age 10 but came off the trajectory and became lean in adulthood ( i.e. , not being overweight in adulthood ) did not have a significantly increased risk of diabetes ( 1.02 , 0.741.40 )
. adjusted rrs ( 95% ci ) of type 2 diabetes by somatotype 5 at age 10 , bmi 25 kg / m at age 18 years , and bmi 25 kg / m at baseline ( average age of 34 years ) , after adjustment for age , race , smoking status , parental history of diabetes , parity , age at first birth , and physical activity .
number of cases of type 2 diabetes for each category : 503 for none ; 50 for 10 years ; 21 for 18 years ; 10 for 10 and 18 years ; 1,469 for 34 years ; 260 for 10 and 34 years ; 664 for 18 and 34 years ; and 441 for all ages .
among 109,172 women followed for > 16 years , somatotypes at ages 5 and 10 years were positively associated with the risk of incident type 2 diabetes after adjustment for major risk factors .
however , women who were overweight at age 10 but were lean in adulthood did not have an increased risk of diabetes associated with childhood overweight , underscoring the importance of continued efforts to control adiposity among overweight children .
limited studies have investigated the long - term consequences of childhood overweight and the risk of type 2 diabetes in adulthood , with inferences hindered by small numbers of case subjects and/or lack of differentiation of diabetes type ( 28 ) .
in addition , some studies included case subjects with young age at onset ( < 30 years old ) ( 3,5,7 ) .
one study using data based on records ( 185 cases ) showed that the cumulative incidence of diabetes was doubled ( from 4.2 to 8.4% ) among women in the largest bmi group at age 11 years ( > 17.4 kg / m ) compared with those in the smallest bmi group ( 15.3 kg / m ) ( 4 ) .
in contrast , a study of older french women using recalled body shape , found an association between childhood thinness and diabetes risk ( 8) .
however , this birth cohort vastly differed from the nhsii as demonstrated by > 60% of their case subjects having reported extreme leanness ( somatotype 1 ) at age 8 years , possibly due to their nutritional status having been affected by world war ii ( 8) .
in addition to absolute size , longitudinal changes through different ages are also relevant to the risk of diabetes ( 17,18 ) . under normal development , infants lose weight after 6 months of age and continue doing so until 5 years of age when their adiposity rebounds ( 18 ) .
although we were unable to assess age at adiposity rebound , earlier rebound has been associated with increased risk of type 2 diabetes ( 17 ) , and there is some suggestion that age at rebound matters more than the absolute size of the child at any point in time because it corresponds to weight gain .
our findings of increased risk associated with increases in somatotype and weight gain support the importance of change in size in addition to absolute size . these findings offer support for continued weight reduction efforts across the life span .
moreover , in analyses of the cumulative effect of overweight through childhood , adolescence , and adulthood , the risk for type 2 diabetes was greatest among women reporting overweight by all three measures , even though the difference was marginal when compared with adolescent overweight .
however , women who became lean in adulthood did not have an increased risk of diabetes associated with childhood overweight .
similar observations have been made from other studies of youth overweight and type 2 diabetes or related traits , with findings becoming nonsignificant after accounting for adult bmi ( 6,19,20 ) .
tracking of metabolic risk factors ( e.g. , hdl and triglycerides ) has also been observed after 21 years of follow - up from childhood ( 21 ) , supporting the fact that cumulative overweight is linked with prolonged exposure to metabolic irregularities , putting children on the path to -cell dysfunction earlier .
it should be noted that although there is tracking of overweight to obesity from childhood to adulthood , the trajectory is not fixed from youth ( 18,22 ) .
it has been shown that 1030% of overweight children do not go on to be overweight as adults with conflicting evidence as to whether there is greater tracking in girls than in boys ( 22 ) .
conversely , the majority of adults who are overweight were not in childhood ( 22 ) as confirmed here with only 1220% of the overweight women reporting childhood overweight .
our study had some limitations . although experts have recommended bmi for the measurement of childhood size ( 18,23 ) , we used recalled somatotype .
however , two previous studies have shown that the accuracy of recall between childhood somatotypes and recorded childhood bmi did not differ by adult bmi ( 10,11 ) .
the misclassification of childhood size is thus more likely to be nondifferential , which can not explain the observed positive association between childhood size and type 2 diabetes risk .
in addition , our findings were in agreement with those of other studies that used childhood measures of weight and height ( 4,20 ) .
the generalizability of our findings may be limited to white women who comprised > 95% of our study population .
more research is needed in minority populations who have higher rates of overweight and diabetes ( 1,24 ) .
last , we can not rule out the possibility of residual confounding by unmeasured confounders because of the observational nature of the study . as for strengths ,
the nhsii included a large number of women ( > 3,000 case subjects ) and adjusted for many risk factors .
follow - up for previous studies required recontacting participants in adulthood with low to moderate success rates ( 2060% ) ( 5,7,19,20 ) , whereas we evaluated somatotypes at baseline and > 90% of the women remained for follow - up . in summary ,
women who do not continue to be overweight in adulthood do not have increased risks .
it remains important then to promote lifestyle changes from youth so that the adverse trajectory could be avoided .
multiple interventions to address childhood overweight have been suggested ( 23 ) , but these remain to be fully tested .
 objectiveto determine how childhood overweight , in conjunction with other life course weight characteristics , relates to the development of type 2 diabetes in adulthood.research design and methodsamong 109,172 women in the nurses ' health study ii , body fatness at ages 5 , 10 , and 20 years was assessed by recall using 9-level pictorial diagrams ( somatotypes ) representing extreme thinness ( category 1 ) to obesity ( category 9 ) . 
 recalled weights at age 18 years and adulthood were used to derive bmi . 
 self - reported cases of type 2 diabetes were confirmed by supplementary questionnaire.resultssomatotypes at ages 5 and 10 years were positively associated with diabetes risk ( ptrend < 0.0001 ) . 
 the adjusted relative risk ( rr ) of women with somatotype 6 ( vs. 2 ) at age 5 years was 2.19 ( 95% ci 1.792.67 ) and at age 10 years was 2.57 ( 2.203.01 ) . 
 increases in size by somatotype or by weight gain since age 18 were associated with increased risk . compared with women who were never overweight at any age , women who were overweight as an adult ( bmi > 25 kg / m2 ) but 
 not previously had an adjusted rr of 8.23 ( 7.419.15 ) . 
 the adjusted rr was 15.10 ( 13.2117.26 ) for women who were also overweight at age 10 ( somatotype 5 ) and 18 ( bmi > 25 kg / m2 ) . increased childhood size 
 was not associated with risk among women who did not continue to be overweight in adulthood.conclusionsincreased body size starting from childhood is associated with a greater risk of diabetes in adulthood . 
 however , women who become lean in adulthood do not have an increased risk . 
RESEARCH DESIGN AND METHODS
Assessment of childhood size and weight characteristics
Type 2 diabetes ascertainment
Assessment of covariates
Statistical analysis
RESULTS
CONCLUSIONS