Obese men have more than triple the risk of having a low sperm count and twice the risk of erectile dysfunction compared with men who are not overweight, according to a new study. The study findings will be presented Sunday, June 3, at The Endocrine Society’s 89th Annual Meeting in Toronto.

Obesity previously has been suspected as a possible cause of male infertility. However, there has been no firm evidence of a relationship, said author Dr. Ahmad Hammoud of the University of Utah, where he is a visiting instructor in reproductive endocrinology and infertility. Hammoud said his study showed a direct relationship between increased body weight and two factors that can contribute to male infertility: low sperm production and erectile dysfunction, also called impotence.

The study was performed in 257 male partners of couples being treated at a fertility clinic. Of men whose body mass index (BMI) characterized them as obese (BMI score of 30 or higher), 15 percent had low sperm counts, according to their medical records. Low sperm counts occurred in less than 4 percent of non-overweight patients (BMI less than 25) and in about 7 percent of men who were overweight but not obese (BMI 25-29.9).

Erectile dysfunction was present in nearly 24 percent of obese patients versus 14 percent of overweight men and 12.5 percent of non-overweight patients. The average age of the men was 32.5.

The study found a negative correlation between BMI and sperm motility, meaning as BMI increases, sperm motility decreases. Poor sperm motility is another cause of male infertility.

More studies are needed to find the extent of the relationship between obesity and male infertility, Hammoud stated. “We don’t know whether our results will hold true for the general male population,” he said. “Confirmation of our results will open new avenues for the diagnosis and treatment of infertile men.”

If obesity is linked to male infertility, studies would be needed to determine if weight loss will reverse infertility.