Male obesity associated with lower sperm concentration, count

Compared with lean men, obese men may be more than three times as likely to have low sperm concentration and count.

Researchers of a retrospective analysis studied the effect of obesity on sperm parameters and erectile dysfunction. They enrolled 390 men (mean age, 32.8 years) who presented for infertility treatment. Based on BMI, men were classified as normal weight (<25), overweight (25-30) or obese (≥30). At baseline, 43% of men were overweight, 33% were obese and 24% were normal weight. In addition, 10.5% presented with low sperm counts.

The researchers reported an increasing incidence of oligozoospermia with increasing BMI (normal weight, 5.32%; overweight, 9.52%; and obese, 15.62%).

Findings also revealed an increasing prevalence of low progressively motile sperm count with increasing BMI (normal weight, 4.52%; overweight, 8.93%), with the greatest prevalence among obese men (13.28%).

Researchers reported a nonsignificant trend toward increasing incidence of erectile dysfunction with increasing BMI.

“There is a strong relationship between overweight and obesity and altered sperm parameters,” the researchers wrote. – by Katie Kalvaitis

Fertil Steril. 2008;90:2222-2225.

It is not surprising that there are alterations in the sperm function of obese men because there are a number of endocrine changes dealing with the concentrations of sex hormone binding globulin and free testosterone, which are influenced by the degree of adiposity. Fatter men have greater changes in these two and one might well expect this to be reflected in function of the sperm from these men.

– George A. Bray, MD

Endocrine Today Editorial Board member