Environmental pyrethroid exposure and diabetes in U.S. adults

Pyrethroid insecticides have been used widely as replacements for organophosphate insecticides over the past decades. While several animal studies suggest that exposure to pyrethroids can alter glucose homeostasis, there is only limited evidence of the association between environmental pyrethroid exposure and diabetes risk in human populations. Therefore, we examined the National Health and Nutrition Examination Survey (NHANES) 2007-2010 data to determine the association between environmental pyrethroid exposure and the prevalence of diabetes in the general U.S. population. Using data on 2796 participants aged 20-79 years from NHANES 2007-2010, we estimated odds ratios (ORs) and 95% confidence intervals (CI) of the association between diabetes and urinary metabolite concentration of pyrethroids using logistic regression. The weighted prevalence of diabetes was 10.3%. The weighted geometric means and detection rate of 3-phenoxybenzoic acid (3-PBA), the most common nonspecific pyrethroid metabolite, were 0.41 μg/L (95% CI: 0.38, 0.45) and 72.0%, respectively. After adjusting for sociodemographic, behavioral, and metabolic factors, we found a significant dose-response relationship between urinary 3-PBA as quartile and prevalent diabetes (p-trend=0.007). Compared to the lowest quartile of 3-PBA, the highest quartile had OR of 2.18 (95% CI: 1.18, 4.03) for diabetes. Our finding suggests pyrethroid insecticides as a potential risk factor for diabetes. Further studies should be conducted to confirm our finding and to determine if this association is causal.