Sexual dimorphisms in the associations of BMI and body fat with indices of pubertal development in girls and boys.
BACKGROUND
The effect of obesity and concomitant insulin resistance on pubertal development is incompletely elucidated.


OBJECTIVE
To determine how measures of adiposity and insulin resistance are associated with pubertal maturation in boys and girls.


METHODS
Breast and pubic hair Tanner stage and testicular volume by orchidometry were determined by physical examination in 1066 children. Ovarian volume was estimated by trans-abdominal ultrasound. Fat mass, skeletal age, and fasting serum for insulin and glucose, total T, estradiol, estrone, dehydroepiandrosterone-sulfate, and androstenedione were measured at the National Institutes of Health Clinical Research Center. Convenience sample; 52% obese, 59% female.


RESULTS
Logistic regression identified a significant interaction between sex and obesity for prediction of pubertal development (P ≤ .01). There was a negative association between boys' testicular volume and body mass index (BMI)/fat mass but a positive association between girls' breast stage and BMI/fat mass. Ovarian volume in girls was positively associated with insulin resistance but not with BMI/fat mass. There was a positive association between obesity and measures of estrogen exposure (breast development and skeletal age) in both sexes. Positive correlations were seen for girls between BMI and pubic hair development and between insulin resistance and T production, whereas adiposity was negatively associated with pubic hair in boys.


CONCLUSIONS
Significant sexual dimorphisms in the manifestations of pubertal development are seen in obese girls and boys. Two known effects of obesity, increased peripheral conversion of low-potency androgens to estrogens by adipose tissue-aromatase and increased insulin resistance, may be in large part responsible for these differences.
Section on Growth and Obesity, Program in Developmental Endocrinology and Genetics (M.K.C., E.A.S., N.M.S., L.B.S., S.M.B., A.H.A., J.A.Y.), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland 20892; Division of Endocrinology (M.K.C.), Boston Children's Hospital, Boston, Massachusetts 02115; Department of Medical and Clinical Psychology (L.B.S.), Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814; Clinical Center (T.H.S.), NIH, Bethesda, Maryland 20892; and Division of Nutrition Research Coordination (V.S.H.), NIH and National Institute of Diabetes, Digestive Diseases, and Nutrition, NIH, Bethesda, Maryland 20892.
Melissa K
MK
Crocker
Elizabeth A
EA
Stern
Nicole M
NM
Sedaka
Lauren B
LB
Shomaker
Sheila M
SM
Brady
Asem H
AH
Ali
Thomas H
TH
Shawker
Van S
VS
Hubbard
Jack A
JA
Yanovski
D000273:Adipose Tissue / Q000254:growth & development; D050154:Adiposity / Q000502:physiology*; D000293:Adolescent; D041923:Adolescent Development; D001823:Body Composition; D015992:Body Mass Index; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D063766:Pediatric Obesity / Q000453:epidemiology*; D011627:Puberty / Q000502:physiology*; D012727:Sex Characteristics