Influence of low-level lead and cadmium exposure on reproductive health in men

Abstract

Purpose: There is increasing evidence that occupational and environmental exposure to toxic pollutants may account for the recent declining fertility in men by reducing sperm count and testis function. Lead and cadmium are known reproductive toxicants that accumulate in the human body over a lifetime. In the most of published data, attention has usually been directed towards excessive exposure to these metals. Very few epidemiologic studies have attempted to investigate the influence of low-level lead and cadmium exposure on reproductive health in men. Methods: Blood lead and cadmium, serum zinc, copper and selenium, parameters of semen quality and of reproductive endocrine function were measured in 280 non-smoking men with no occupational exposure to metals. The interrelationship of all the measured parameters, including age and alcohol consumption, was calculated by forward stepwise multiple regression. Results of the study: The median and range values for blood lead were 32 (6-149) ug/L and for cadmium 0.34 (<0.05-3.7) ug/L. After adjusting for potential confounding variables, blood lead was significantly associated with an increase in testosterone (P<0.005) and immature sperm concentration (P<0.002) and a decrease in percentages of slight amorph sperm (P<0.0001), whereas blood cadmium was significantly associated with an increase in percentage of slow sperm (P<0.005). These results indicate that even low-level lead and/or cadmium exposure may have adverse effects on male reproductive health.