Extra Weight Tied To Male Infertility In New Study

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 the National Institute of Environmental Health Sciences, 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.

"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, meaning the men and their wives failed to get pregnant after 12 months of trying.

Researchers screened out couples where the wives were 40 or older, since fertility in women declines sharply in those years.

The results are published in the September issue of the journal Epidemiol- ogy.

Before public health alarms get 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 inquire whether losing weight diminishes the risk of infertility among men.

"The little bit of research that exists on women suggests that is the case. It would be my hypothesis that would be true for men too," Baird said.

Multiple questions concerning 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 lean toward 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 a group of 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 weigh reported the same.

The good news is that more research shows that even moderate weight loss can reduce those difficulties.

Catherine Clabby