Improvement in semen quality associated with decreasing occupational lead exposure

Background Cross-sectional studies have suggested that occupational lead ex posure may adversely affect sperm quality. Methods Sperm quality changes were prospectively assessed in 19 men employe d at a car battery plant where efforts were made to decrease the exposure l evel. The participants delivered monthly samples of semen and venous blood during their employment at the factory. The factory then closed, and additi onal samples were obtained from 16 of the men. Results Average blood-lead concentrations decreased from 2.03 mu mol/l to 0 .96 mu mol/l during the observation period. Concomitantly, significant impr ovements were seen in the proportion of motile cells both at sample deliver y and after 24 hr, and in penetration. However the sperm cell concentration and the proportion of morphological abnormalities did not change. Conclusions These results support the notion that occupational lead exposur e at currently acceptable levels has a small adverse effect on sperm qualit y especially sperm motility, and that this effect is at least partially rev ersible. (C) 1999 Wiley-Liss, Inc.