Gentlemen, here’s one more reason to stay slim: Packing on extra pounds may increase the risk of male infertility, a new study says.
The preliminary research, conducted at a federal institute in Research Triangle Park, finds that the heavier one group of men became, the greater their chances of fertility woes. That’s sobering news in a country confronting an obesity epidemic.
In North Carolina alone, nearly 26 percent of adults are obese and another 37 percent are overweight, according to the latest tally. “We know more and more men have become overweight but no one has looked at this fertility issue before,” said Donna Day Baird, a National Institute of Environmental Health Sciences researcher involved with the study. Baird’s team didn’t actually set out to explore the topic. But while mining data on the health of a large group of North Carolina and Iowa farmers, they spotted signs of fertility problems. When they sorted the men by weight, the frequency of infertility rose along with heft. A 20-pound increase in men’s weight correlated to a 10 percent increase in infertility.
Infertility is defined as a couple’s failure to achieve pregnancy after 12 months of trying. Researchers screened out couples where the wives were 40 or older, because fertility in women declines sharply in those years. The results, released Thursday, are published in the September issue of the journal Epidemiology. Before public health alarms are sounded, Baird said, she wants to confirm the findings in additional groups of men — a project she has started with data collected in Norway. If the findings hold, researchers should also ask whether losing weight diminishes the risk of infertility among men. “The little bit of research that exists on women suggests that is the case,” Baird said. “It would be my hypothesis that would be true for men, too.” Questions about male infertility linger already. Recent federal estimates say about 9 percent of married couples trying to conceive encounter infertility problems. Research attributes at least 25 percent of the difficulty to men. But treatment of male infertility works only once every five times, as opposed to 80 percent of the time for women.
This new infertility study doesn’t answer why overweight men may may have more fertility problems. But earlier research has shown that overweight men can have reduced sperm counts, for instance, and lower testosterone levels. It could also be that overweight men have less sex. Research at Duke University two years ago showed that men and women seeking treatment for obesity experience more sexual impairments than people outside treatment. In that study, involving 506 weight-loss patients, 41 percent said they either didn’t enjoy sexual activity, had no sexual desire, experienced difficulty with sexual performance or avoided sex. Only 5 percent of people with normal weight reported the same. The good news is that more research shows that even moderate weight loss can reduce those difficulties. All this emphasizes the need to better understand and help with sexual problems among people who are overweight, said psychologist Martin Binks, one of the Duke researchers. Sex, after all, is a basic part of human experience. But it would be easier if people could figure out how to prevent the spread of obesity in the first place. “How do we avoid these things to begin with rather than try to treat them?” he asked.
Staff writer Catherine Clabby can be reached at 956-2414 or