Testicular Dysfunction in Systemic Diseases

To examine the relationship between body mass index (BMI) and semen quality among young men from the general population. Cross-sectional study. Danish young men were approached when they attended a compulsory physical examination to determine their fitness for military service. From 1996-1998, 1,558 (19%) young men (mean age 19 years) volunteered. 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. Serum T, sex hormone-binding globulin (SHBG), and inhibin B all decreased with increasing BMI, whereas free androgen index and E(2) increased with increasing BMI. Serum FSH was higher among slim men. After control for confounders, men with a BMI 25 kg/m(2) 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/m(2). 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. 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.

The relation between endogenous testosterone concentrations and health in men is controversial. We examined the prospective relationship between endogenous testosterone concentrations and mortality due to all causes, cardiovascular disease, and cancer in a nested case-control study based on 11 606 men aged 40 to 79 years surveyed in 1993 to 1997 and followed up to 2003. Among those without prevalent cancer or cardiovascular disease, 825 men who subsequently died were compared with a control group of 1489 men still alive, matched for age and date of baseline visit. Endogenous testosterone concentrations at baseline were inversely related to mortality due to all causes (825 deaths), cardiovascular disease (369 deaths), and cancer (304 deaths). Odds ratios (95% confidence intervals) for mortality for increasing quartiles of endogenous testosterone compared with the lowest quartile were 0.75 (0.55 to 1.00), 0.62 (0.45 to 0.84), and 0.59 (0.42 to 0.85), respectively (P<0.001 for trend after adjustment for age, date of visit, body mass index, systolic blood pressure, blood cholesterol, cigarette smoking, diabetes mellitus, alcohol intake, physical activity, social class, education, dehydroepiandrosterone sulfate, androstanediol glucuronide, and sex hormone binding globulin). An increase of 6 nmol/L serum testosterone ( approximately 1 SD) was associated with a 0.81 (95% confidence interval 0.71 to 0.92, P<0.01) multivariable-adjusted odds ratio for mortality. Inverse relationships were also observed for deaths due to cardiovascular causes and cancer and after the exclusion of deaths that occurred in the first 2 years. In men, endogenous testosterone concentrations are inversely related to mortality due to cardiovascular disease and all causes. Low testosterone may be a predictive marker for those at high risk of cardiovascular disease.