Body mass index in relation to semen quality and reproductive hormonesamong 1,558 Danish men
Received 15 October 2003; received in revised form 15 March 2004; accepted 15 March 2004.
Objective
To examine the relationship between body mass index (BMI) and semen quality among young men from the general population.
Design
Cross-sectional study.
Setting
Danish young men were approached when they attended a compulsory physical examination to determine their fitness for military service.
Patient(s)
From 1996–1998, 1,558 (19%) young men (mean age 19 years) volunteered.
Main outcome measure(s)
Semen volume (in milliliters), sperm concentration (in million per milliliter), percentage of motile spermatozoa, percentage of spermatozoa with normal morphology, total sperm count (in million), and testis size (in milliliters). In addition, serum reproductive hormones were measured.
Result(s)
Serum T, sex hormone-binding globulin (SHBG), and inhibin B all decreased with increasing BMI, whereas free androgen index and E2 increased with increasing BMI. Serum FSH was higher among slim men. After control for confounders, men with a BMI <20 kg/m2 had a reduction in sperm concentration and total sperm count of 28.1% (95% confidence interval [CI] 8.3%–47.9%) and 36.4% (95% CI 14.6%–58.3%), respectively, and men with a BMI >25 kg/m2 had a reduction in sperm concentration and total sperm count of 21.6% (95% CI 4.0%–39.4%) and 23.9% (95% CI 4.7%–43.2%), respectively, compared to men with BMI between 20–25 kg/m2. Percentages of normal spermatozoa were reduced, although not significantly, among men with high or low BMI. Semen volume and percentage of motile spermatozoa were not affected by BMI.
Conclusion(s)
High or low BMI was associated with reduced semen quality. It remains to be seen whether the increasing occurrence of obesity in the Western world may contribute to an epidemic of poor semen quality registered in some of the same countries. If so, some cases of subfertility may be preventable.
aUniversity Department of Growth and Reproduction, Rigshospitalet, Copenhagen, Denmark
bDepartment of Environmental Medicine, University of Southern Denmark, Odense, Denmark
cDepartment of Biostatistics, University of Copenhagen,Copenhagen, Denmark
Reprint requests: Tina Kold Jensen, M.D., Ph.D., University Department of Growth and Reproduction, GR 5064, Rigshospitalet, Blegdamsvej 9, 2100 Copenhagen, Denmark (FAX: 45-35456054
Supported by the European Union (contract no. QLK4-1999-01422/BMH4-CT96-0314), Danish Environmental Agency, Danish Research Council (grant no. 9700883 and SV1736).
ABSTRACT