In girls with excess total body fat, puberty looks different, both in terms of both reproductive hormones and breast maturation. A team led by NIEHS researchers, with collaborators from the National Cancer Institute and U.S. Centers for Disease Control and Prevention, published these findings Feb. 25 in the Endocrine Society’s Journal of Clinical Endocrinology and Metabolism.

The Body Weight and Puberty Study was the first pediatric study in people to be conducted at the NIEHS Clinical Research Unit. (Photo courtesy of energyy / iStock.com)

Changes to hormone levels

Previous studies reported that girls with obesity start puberty and experience their first menstrual period earlier than girls with normal weight.

“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,” said senior study author Natalie Shaw, M.D., in a press release from the Endocrine Society. Shaw leads the NIEHS Pediatric Neuroendocrinology Group.

Shaw said for studies like hers, it is important to compare girls who are lean and girls with obesity who are at the same stage of puberty. (Photo courtesy of Steve McCaw / NIEHS)

“In some girls with higher total body fat, higher testosterone levels were associated with irregular menstrual cycles, acne, and excess body hair,” she continued. “In late puberty, girls with greater body fat also showed earlier menarche and delayed breast maturation, as determined by breast ultrasound.” Menarche occurs when a girl has her first menstrual period.

The researchers did not find associations between amount of body fat and maturation of the ovaries or uterus.

Multiple approaches reveal differences

The team studied 90 girls between 8 and 15 years old who live in North Carolina over the course of four years. Thirty-six had obesity, and 54 had normal weight. Researchers used a variety of approaches.

• Total body fat calculation using dual-energy x-ray absorptiometry, or DXA scan.
• Puberty tracking via Tanner staging.
• Breast and pelvic ultrasounds.
• Measurement of hormone levels in blood samples.
• Recording each girl’s age at her first period.

After analyzing all the data, the researchers found several differences for girls with higher total body fat, compared to girls with lower body fat.

• Slower development of mature breasts.
• Younger age at first period.
• Higher levels of certain reproductive hormones.
  • Follicle-stimulating hormone, or FSH, is made by the brain.
  • The peptide inhibin B is made by the ovaries.
  • Male-like hormones, such as testosterone and androstenedione, are made by adrenal glands or ovaries.

“The long-term consequences of these differences in puberty markers deserve further study,” she said.

The authors presented the research March 20 at ENDO 2021, the Endocrine Society’s annual meeting.

Citation: Ortega MT, McGrath JA, Carlson L, Flores Poccia V, Larson G, Douglas C, Sun BZ, Zhao S, Beery B, Vesper HW, Duke L, Botelho JC, Filie AC, Shaw ND. 2021. Longitudinal investigation of pubertal milestones and hormones as a function of body fat in girls. J Clin Endocrinol Metab; doi:10.1210/clinem/dgab092 [Online 25 February 2021].

(This article is from the Endocrine Society’s press release.)