Obesity and infertility: The search for a link

May 1, 2011

Obesity is associated with hormonal dysfunction and with impaired spermatogenesis. What remains unknown is the causal factor.

Obesity is a true epidemic in the U.S. According to the Centers for Disease Control and Prevention, approximately one-third of U.S. adults are overweight, a slightly higher fraction are obese, and another 6% are extremely obese. Investigators have increasingly focused on how obesity may negatively affect health beyond cardiovascular disease and diabetes. A relatively recent avenue of research examines the impact of excessive weight on sperm quality and male fertility.

In short, obesity is associated with hormonal dysfunction and with impaired spermatogenesis. What remains unknown is the causal factor. Is it hormonal dysfunction that leads to obesity, or the converse? And is it an impaired endocrine system that throws a wrench into the sperm works, or is another bad cog the culprit? It certainly makes sense to counsel your obese male patient to lose weight for the sake of his overall health, but you may also want to explain that his weight may be putting the brakes on his sperm quality.

It's critical that future research tease out the factor that causes infertility in obese men. Current data only provide a correlation. It's my hope that obesity is the culprit because modifying lifestyle factors would then improve a man's fertility. In the absence of definitive data, however, I still counsel my overweight patients to lose weight in a gentle, structured fashion.

Dr. Niederberger, a member of the Urology Times Editorial Council, is professor and head of urology at the University of Illinois, Chicago.