Occupational and environmental exposures to heavy metals: risk factors for male infertility in Lebanon?

A case-control study was conducted to examine whether occupational or environmental exposures, particularly to heavy metals, are associated with male infertility in Lebanon, a war-torn country with a history of environmental degradation. Seventy-four infertile cases and 76 fertile controls were selected from 2 major fertility clinics in Beirut. Data collection involved risk-factor interviews, semen analysis, and blood collection for heavy metal analysis. Multiple regression analysis showed that men with reported occupational exposures were twice as likely to be infertile as unexposed men. However, none of the subcategories of infertile men (based on semen analysis results) had significantly higher whole blood concentrations of heavy metals when compared to fertile controls. Blood concentrations were well within the range for referent populations of healthy individuals. Thus, despite Lebanon's poor record of occupational and environmental stewardship, exposure to metal pollutants does not appear to represent an important risk factor for male infertility.