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.