Semen Quality Lower in Men from Rural Areas-Part II

Shanna H. Swan, Ph.D.
University of Missouri-Columbia School of Medicine
R01ES09916

Background: In a study published in April 2003, NIEHS-supported researchers reported that semen quality was found to be lower in a cohort of men living in an agrarian area in Missouri as compared to men from more urban locations. The authors speculated that a possible reason for these differences could be higher exposure to agricultural chemicals in the more rural Missouri population. Fifty-seven percent of the land in the Columbia, MO area is used for farming which far exceeds that of the other areas. The authors have conducted a follow-up study to determine whether exposure to eight commonly used pesticides is associated with changes in semen quality in two groups of men from Missouri and Minnesota.

Advance: Pesticide metabolites were measured in the urine of all men participating in the study. Pesticide metabolite levels were elevated in Missouri men, compared with controls, for the herbicides alachlor and atrazine, and for the pesticide diazinon. Men from Missouri with high levels of alachlor or diazinon were 30 and 16.7 times more likely to have poor semen quality. There were no associations for any pesticide exposure in the group of men from Minnesota where agricultural pesticides were low or for the commonly used mosquito repellant DEET or the insecticide Malathion.

Implication: The reported associations between pesticide exposure, confirmed by urine analysis, and poor semen quality in the Missouri men suggest that agricultural chemicals may be the cause of these effects. The researchers report, "This is the first population-based study to demonstrate links between specific biomarkers of environmental exposures and biomarkers of male reproduction in humans." They go on to conclude, "Given the current wisespread use of these pesticides, if further study confirms these findings, the implications for public health and agricultural practice could be considerable."

Citation: Swan SH, Kruse RL, Liu F, Barr DB, Drobnis EZ, Redmon JB, Wang C, Brazil C, Overstreet JW; Study for Future Families Research Group. Semen quality in relation to biomarkers of pesticide exposure. Environ Health Perspect. 2003 Sep;111(12):1478-84.