Association between urinary biomarkers of exposure to organophosphate insecticides and serum reproductive hormones in men from NHANES 1999–2002

•We studied 7 urinary OP insecticide metabolites in men 20–55 years old from NHANES.•Biomarkers were detected in >50% of the samples, except for DEDTP, DMP, and DMDTP.•There was a statistically significant inverse association between DEP and T.•Exposure to certain OP insecticides may have important implications for male health.

Exposure to organophosphate (OP) insecticides may alter reproductive hormone levels in men and increase the risk for poor reductive health and other adverse health outcomes. However, relevant epidemiology studies in men are limited. We evaluated urinary concentrations of OP metabolites (3,5,6-trichloro-2-pyridinol and six dialkyl phosphates) in relation to serum concentrations of testosterone (T) and estradiol among 356 men aged 20–55 years old from the U.S. National Health and Nutrition Examination Survey. Biomarkers were detected in greater than 50% of the samples, except for diethyldithiophosphate, dimethylphosphate, and dimethyldithiophosphate. In adjusted regression models, we observed a statistically significant inverse relationship between diethyl phosphate (DEP) and T when DEP was modeled as either a continuous or categorical variable. These findings add to the limited evidence that exposure to certain OP insecticides is linked to altered T in men, which may have important implications for male health.