High BMI linked to reduced inhibin B, sperm quality

March 1, 2007

New Orleans-Men with high body mass index values have lower serum inhibin B levels, according to a report from Reproductive Biology Associates, Atlanta. The study's authors point out that additional research is needed to determine whether increased BMI affects men's fertility.

Inhibin B, a glycoprotein hormone produced by the Sertoli cells of the testes, suppresses pituitary synthesis of follicle stimulating hormone and may also have an additional paracrine role within the testes. Low serum inhibin B levels are indicative of poor or absent spermatogenesis. BMI has been shown to negatively affect sperm quality (ie, chromatin integrity) and quantity (ie, normal-motile counts), as well as reproductive endocrine levels (ie, lower serum testosterone).

"Little to no information is available with regard to the impact that BMI has on inhibin B levels," said lead study author William E. Roudebush, PhD, manager of reproductive endocrinology, Beckman Coulter, Inc., Chaska, MN, whose aim was to evaluate associations between BMI and inhibin B.

Men presenting with BMI >30 kg/m2 had significantly lower (p<.05) inhibin B levels than did men presenting with BMI <30 kg/m2.

"We observed an inverse relationship between BMI and serum inhibin B, with men presenting with a high BMI (>30) typically found to have abnormal levels," he said.