Higher Total Body Fat in Girls Associated With Differences in Hormonal Changes During Puberty

Girls with higher total body fat (TBF) during late puberty have increased levels follicle-stimulating hormone (FSH), inhibin B, estrone, total and free testosterone, and androstenedione over time as well as menarche compared with girls with lower total body fat, according to a study in the Journal of Clinical Endocrinology and Metabolism.

This longitudinal study included 90 healthy girls between 8.2 and 14.7 years of age (mean age, 10.9±1.3 years) who completed a mean of 2.8±1.7 study visits over a 4-year period. Girls were classified as overweight/obese (n=36) and normal weight (n=54), based on the age-adjusted body mass index scale.

At each visit, participants underwent dual-energy x-ray absorptiometry to measure total body fat. Additionally, the investigators performed Tanner staging, breast ultrasound for morphological staging (BMORPH), pelvic ultrasound, hormone tests, and assessment of menarchal status. Researchers also evaluated the effect of total body fat on pubertal markers in analyses controlled for baseline BMORPH.

At baseline, girls who were of normal weight were significantly older (11.3 vs. 10.2 years, p<0.01) and presented with more advanced BMORPH (p<0.01) compared with those who were overweight/obese.

Overall, levels of luteinizing hormone, estradiol, and ovarian and uterine volumes increased over time. Mean total body fat did not seem to affect progression through early stages of breast development, according to analysis of BMORPH transitions using multi-state modeling. Higher mean total body fat was associated with a slower progression out of breast stage D compared with lower mean total body fat.

Levels for FSH, inhibin B, estrone, total and free testosterone, and androstenedione were all initially similar between groups. After just 1 year, however, levels for these values increased in participants with higher total body fat. In contrast, levels of these values plateaued in girls with mid-range TBF and decreased in those with lower total body fat.

The overall median age at menarche was 12.4 years. For every 1-unit increase in visit 1 total body fat, the chance of achieving menarche at any time was 3% higher in girls who with higher total body fat (hazard ratio, 1.03; 95 CI, 1.00-1.07; P =.05).

The majority of girls in this study did not complete visits beyond the second visit, and researchers did not measure markers of other health effects associated with high total body fat, such as inflammation or insulin resistance.

According to the researchers, further study is needed to investigate “the mechanistic basis for these differences and their potential clinical consequences in girls with higher total body fat.”

Reference

Ortega MT, McGrath JA, Carlson L, et al. Longitudinal investigation of pubertal milestones and hormones as a function of body fat in girls. Published online February 25, 2021. J Clin Endocrinol Metab. doi:10.1210/clinem/dgab092