Sexual dimorphisms in the associations of BMI and body fat with indices of pubertal development in girls and boys.

CONTEXT: 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. SETTING AND DESIGN: 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.

Eating patterns in youth with and without loss of control eating.

OBJECTIVE: To compare the characteristic meal patterns of adolescents with and without loss of control (LOC) eating episodes. METHOD: The Eating Disorder Examination was administered to assess self-reported LOC and frequency of meals consumed in an aggregated sample of 574 youths (12-17 years; 66.6% female; 51.2% Caucasian; BMI-z: 1.38 ± 1.11), among whom 227 (39.6%) reported LOC eating. RESULTS: Compared to those without LOC, youth with LOC were less likely to consume lunch and evening meals (p's < .05), but more likely to consume morning, afternoon, and nocturnal snacks (p's ≤ .05), accounting for age, sex, race, socio-economic status, BMI-z, and treatment-seeking status. DISCUSSION: Adolescents with reported LOC eating appear to engage in different meal patterns compared to youth without LOC, and adults with binge eating. Further research is needed to determine whether the meal patterns that characterize adolescents with LOC play a role in worsening disordered eating and/or excessive weight gain.