Environmental and occupational exposures as a cause of male infertility.

OBJECTIVES: To determine the association between environmental and occupational exposures, semen parameters and lead (Pb) and cadmium (Cd) levels in seminal plasma of men investigated for infertility. METHODS: Data were collected from 300 men investigated for infertility using an interviewer administered questionnaire. Seminal fluid analysis and classification was done according to WHO guidelines. Positive exposure was defined as environmental or occupational exposure to agro or industrial chemicals, heavy metals and living in areas within 50 m of potential sources of pollution for three months or more. Seminal plasma lead and cadmium levels were estimated by graphite furnace atomic absorption spectrophotometry after digestion with nitric acid. The means of sperm parameters, Pb and Cd concentrations between exposed and non exposed groups were compared using t-test. RESULTS: Mean age was 34.8 (95% CI 34.2-35.4) years BMI was 24.3 (95% CI 23.8-24.7) kg/m2 and duration of the infertility was 45.7 (41.7-49.6) months. In this study, 54.6% were exposed to toxins through environmental or occupational sources. All sperm parameters were lower in the exposed group when compared to the non exposed. Lead and cadmium were detected in 38.3% and 23% of men respectively. The distance from the source of possible environmental or occupational exposure was negatively correlated to seminal plasma Pb (r=0.06, p>0.05) and Cd (r=0.26, p<0.05) concentrations. In the exposed, mean lead concentration was 17.7 (95% CI 15.0-20.4) µg/dl and 13.5 (95% CI 11.2-15.7) µg/dl in non exposed and cadmium concentration in exposed was 1.2 (95% CI 1.1-1.4) µg/dl and 1.1 (0.9-1.3) µg/dl in non-exposed. CONCLUSIONS: Environmental and occupational exposures were associated with reduced sperm count motility, viability, normal forms and detectable levels of lead and cadmium in seminal plasma.

Cost-effective diagnosis of male oxidative stress using the nitroblue tetrazolium test: useful application for the developing world.

Seminal oxidative stress plays an important role in male factor infertility (MFI), worldwide. A study was thus undertaken for the first time to establish seminal reactive oxygen species (ROS) as a clinical marker of MFI in a cohort of Sri Lankan males. The nitro blue tetrazolium (NBT) assay for ROS estimation and modified Endtz test for detecting leucocytes were carried out on semen samples (N = 102) of subfertile males. Age-matched individuals (N = 30) with proven past paternity served as controls. Significantly higher ROS production was evident in individuals with asthenozoospermia and unexplained infertility (Mann-Whitney U-test, P = 0.000), than in the fertile and the other subfertile groups tested. Receiver operating characteristic plot analysis established cut-off points of 40.57 and 42.02 µg formazan/10(7) spermatozoa for ROS to distinguish fertile males from asthenozoospermics (71.4% sensitivity: 70% specificity; AUC = 0.82), and from unexplained infertile males (74.1 % sensitivity: 73.3% specificity; AUC = 0.85) respectively. As ROS appear to be a potential marker of male infertility, it is imperative to validate this test as a simple, cost-effective hence a widely accessible diagnostic tool to be included in MFI investigations in the developing world.