Obese teenagers may have up to 50% less total testosterone than their normal-weight peers, according to researchers from the State University of New York at Buffalo’s School of Medicine and Biomedical Sciences.
The lower testosterone levels can contribute to increased abdominal fat, decreased muscle mass, and slower sexual maturation. They may also lead to eventual diabetes and fertility problems.
Testosterone is a hormone that drives much of a boy’s sexual development, such as facial hair growth and the broadening of the shoulders. It is also responsible for sperm development and sex drive.
The study participants were 50 males between the ages of 14 and 20. Twenty-five participants were above a 95th percentile benchmark for body mass index (BMI) and were considered obese. The remaining 25 teenagers were considered lean, as their BMIs fell below an 85th percentile benchmark.
The researchers took morning fasting blood samples and measured levels of free testosterone (which is not bound to another substance), total testosterone (both free and bound), and estradiol, an estrogen hormone.
After controlling for age and sexual maturity, the researchers found that the obese participants had 40% to 50% less total testosterone than the lean participants.
The authors noted that these results should be confirmed in a larger study.
“The implications of our findings are, frankly, horrendous because these boys are potentially impotent and infertile,” said lead author Paresh Dandona, MD, PhD in a press release. “The message is a grim one with massive epidemiological implications.”
Dr. Dandona is chief of the Division of Endocrinology, Diabetes, and Metabolism at the University at Buffalo School of Medicine.
“These findings demonstrate that the effect of obesity is powerful, even in the young, and that lifestyle and nutritional intake starting in childhood have major repercussions throughout all stages of life,” Dr. Dandona added.
The study has been peer reviewed and accepted for publication by Clinical Endocrinology. It is available online in its pre-publication form.
The Chart (CNN Health)
“'Alarming' low testosterone levels found in obese teenage boys”
(October 12, 2012)
Mogri, Muniza, et al.
“Testosterone Concentrations in Young Pubertal and Post-pubertal Obese Males”
(Accepted article. Manuscript accepted online: September 13, 2012)
Medical News Today
“Obese Teen Boys Have Lower Testosterone Levels”
(October 17, 2012)
The State University of New York at Buffalo
“Obese Teen Boys Have Up to 50 Percent Less Testosterone than Lean Boys, UB Study Finds”
(Press release. October 12, 2012)