New study shows girls with excess body fat developed fully mature breasts more slowly but started their period sooner.
Puberty looks different, in terms of both reproductive hormones and breast maturation, in girls with excess total body fat, according to a new study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism.
Previous studies found that girls with obesity start puberty and experience their first menstrual period earlier than girls with normal weight. It is unknown if excess body fat can alter not only the timing of puberty, but also a girl’s reproductive hormone levels and development of reproductive organs such as the breasts, ovaries and uterus.
“We found that in mid- to late puberty, girls with greater total body fat demonstrated higher levels of some reproductive hormones including follicle-stimulating hormone (FSH), inhibin B, and male-like hormones such as testosterone. In some girls with higher total body fat, higher testosterone levels were associated with irregular menstrual cycles, acne and excess body hair,” says study author Natalie D. Shaw, MD, of the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health (NIH) in Durham, N.C. “In late puberty, girls with greater body fat also showed delayed breast maturation, as determined by breast ultrasound, and earlier menarche. There were no differences in maturation of the ovaries or uterus as a function of body fat.”
The researchers studied 90 girls between 8 and 15 years old (36 with obesity, 54 with normal weight) over the course of four years. They calculated total body fat using dual-energy x-ray absorptiometry (known as a DXA scan), tracked puberty using Tanner staging, conducted breast and pelvic ultrasounds, measured hormones levels in blood samples, and recorded each girl’s age at her first period. The researchers found that girls with higher total body fat had differences in reproductive hormone levels, developed mature breasts more slowly and got their first period earlier than girls with lower total body fat.
“The long-term consequences of these differences in puberty markers deserves further study,” Shaw says.
Other authors of the study include: Madison T. Ortega, Lauren Carlson, Vanessa Flores Poccia, Bob Z. Sun, Shanshan Zhao and Breana Beery of the NIEHS; John A. McGrath, Gary Larson and Christian Douglas of Social & Scientific Systems, Inc., in Durham, N.C.; Hubert W. Vesper, Lumi Duke and Julianne C. Botelho of the Centers for Disease Control and Prevention in Atlanta, Ga.; and Armando C. Filie of the National Cancer Institute of the NIH in Bethesda, Md.
The manuscript received funding from the NIEHS.
The manuscript, “Longitudinal Investigation of Pubertal Milestones and Hormones as a Function of Body Fat in Girls,” was published online, ahead of print.
The authors will be presenting related research at ENDO 2021, the Endocrine Society’s annual meeting.