Semen quality and reproductive hormones in Faroese men: a cross-sectional population-based study of 481 men

Objectives: To determine semen quality and reproductive hormone levels in young Faroese men. Design: Descriptive cross-sectional study of Faroese men compared with Danish men. Setting: Faroese one-centre study. Participants: 481 men born from 1981 to 1987 and investigated from 2007 to 2010. Outcome measures: Sperm concentration, semen volume, total sperm count, sperm motility, sperm morphology and reproductive hormone levels. Results: Sperm concentrations for the Faroese men were lower than for the Danish men (crude median 40 vs 48 mill/ml, p<0.0005). Semen volume was higher, and thus the total sperm counts did not differ (159 vs 151 mill, p=0.2). Motility and morphology did not differ between the Faroese and Danes. The inhibin B/follicle-stimulating hormone ratios for the Faroese men were lower than for the Danes (64 vs 76, p=0.001). Similarly, lower total testosterone/luteinising hormone (LH) ratio (4.6 vs 6.0, p<0.0005) and lower calculated free-testosterone/LH ratio (94 vs 134, p<0.0005) were detected for the Faroese men. Conclusions: Semen quality among the Faroese men is at the same low level as reported for Danish men, and the reproductive hormone levels furthermore indicated a lower Leydig cell capacity for testosterone production. The influence of environmental exposure and genetic factors on semen quality has to be studied further.