Here’s another reason for men to get into shape, for a new study has found that obese men are significantly more likely to be infertile.
The study was conducted by researchers at the National Institute of Environmental Health Sciences (NIEHS), one of the National Institutes of Health who analysed 1,468 couples enrolled in the Agricultural Health Study (AHS), a large project that began in 1993 examining factors that impact the health of farmers and their families in agricultural communities.
Markku Sallmen, lead author on the paper, said that the study showed that even a 20-pound increase in men’s weight can see a drop in their ability to father children.
"The data suggest that a 20-pound increase in men's weight may increase the chance of infertility by about 10 percent," Sallmen said.
Donna Baird, Ph.D., an NIEHS epidemiologist, said that though research had been conducted to show that women’s weight also effects their chances of getting pregnant, this was the first research that studied the effect of obesity on fertility of men.
"Women who are overweight or obese tend to have a more difficult time becoming pregnant than normal-weight women, but whether men who are overweight or obese also have fertility problems had not been studied," she said.
As a part of the study the researchers divided the couples into infertile and fertile groups. The infertile couples were those that tried for longer than a year to conceive, and the fertile couples were those that conceived within a year.
They found that men's BMI was an independent risk factor for infertility, and even when they adjusted for other factors that could affect fertility, including high BMI of the woman, age, cigarette smoking, alcohol intake, and solvent and pesticide exposure, they found that there was a general increase in infertility with increased BMI, reaching a nearly 2-fold increase among obese men.
When researchers divided the sample into two equal groups by men's age, they found that men's BMI was a risk factor for infertility in both the older and younger men.
"This study provides data on some additional health problems associated with obesity. Preventing obesity can help improve men's overall health, perhaps even their reproductive health," said David A. Schwartz, M.D., director of the National Institute of Environmental Health Sciences.
The study is published in the September 2006 issue of Epidemiology.