Effects of environmental and occupational pesticide exposure on human sperm: a systematic review

Relatively recent discoveries of the hormone disrupting properties of some pesticides have raised interest in how contemporary pesticide exposures, which primarily take the form of low level environmental or occupational exposures, impact spermatogenesis. The objective of the present review was to summarize results to date of studies examining pesticide effects on human sperm. Outcomes evaluated included sperm parameters, DNA damage and numerical chromosome aberrations (aneuploidy (disomy, nullisomy) or diploidy). Studies investigating sperm in men environmentally and/or occupationally exposed to any types of pesticides were included in the review. The targeted literature search over the last 15 years showed a range of pesticide classes have been investigated including pyrethroids, organophosphates, phenoxyacetic acids, carbamates, organochlorines and pesticide mixtures. None of the studies involved acute exposure events such as chemical accidents. There were 20 studies evaluating semen quality, of which 13 studies reported an association between exposure and semen quality; 6 studies evaluating DNA damage, of which 3 reported an association with exposure; and 6 studies assessing sperm aneuploidy or diploidy, of which 4 reported an association with exposure. Studies varied widely in methods, exposures and outcomes. Although suggestive for semen parameters, the epidemiologic evidence accumulated thus far remains equivocal as to the spermatotoxic and aneugenic potential of pesticides given the small number of published studies. This question warrants more investigation and suggestions for future studies are outlined.