Urinary concentrations of permethrin metabolites in US Army personnel in comparison with the US adult population, occupationally exposed cohorts, and other general populations.

Permethrin is used to treat clothing as a personal protective measure against insect bites in military and recreational settings, and along with other pyrethroid insecticides, is sprayed in agricultural and residential sites for pest control. The widespread use of permethrin and other pyrethroid insecticides creates a potential for human exposure in occupational and non-occupational populations. This study aims to compare urinary biomarkers of pyrethroid exposure in two US military cohorts to the general US adult population from the 2009-2010 Nutritional Health and Nutrition Examination Survey (NHANES). Additional comparisons are made to previously published biomonitoring data from occupational and population cohort studies. Urine samples from two US military cohorts were analyzed for 3 permethrin metabolites: 3-phenoxybenzoic acid (3-PBA), and cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (DCCA). Biomarker concentrations were adjusted for creatinine. Geometric means were calculated and then compared to creatinine-adjusted concentrations of 3-PBA and trans-DCCA in US adults (aged 20-59) using data collected as part of the 2009-2010 NHANES. Sex- and race-standardized geometric means were calculated separately for each of the US military groups using the demographic distributions from NHANES 2009-2010. Data from other military, occupational, and non-occupational population studies were extracted from the literature for further comparison. The two US military cohorts' geometric mean values, non-standardized and standardized, were markedly higher than what was observed in the general US adult population. Biomarkers of permethrin exposure were detected at a high frequency in military personnel wearing treated uniforms (90-100%). Detection rates of these biomarkers were similarly high in other studies of occupational exposure (67-100%) to pyrethroid insecticides. Adjusting for creatinine, the concentrations observed in the military groups were generally higher than levels seen in the general US adult population (NHANES, 2009-2010), other occupational groups (e.g., farmworkers, flight attendants, and pest control workers), and population cohorts from other countries.