Association of exposure to organophosphate pesticides with reproductive lifespan

Organophosphate pesticides (OPs) have been found to have reproductive toxicity with overt endocrine disruption potential, yet the relationships between OPs with reproductive lifespan remain unexplored. We aimed to investigate associations between urinary OP concentrations with reproductive lifespan. This study included 1,356 postmenopausal women who participated in the National Health and Nutrition Examination Survey from 1999 to 2018 to evaluate the relationship between OP exposure and reproductive lifespan. Urine was analysed using gas chromatography coupled with mass spectrometry for concentrations of six dialkyl phosphate (DAP) metabolites of OPs. Multivariate linear regression and Bayesian kernel machine regression (BKMR) models revealed that total urinary DAP metabolite concentrations (β = 0.10, 95% CI: 0.03–0.17, p = 0.006) were positively associated with age at menopause. Urinary dimethyl phosphate (DMP) concentration was positively associated with age at menopause (β = 0.67, 95% CI: 0.30–1.03, p = 0.001) and reproductive lifespan (β = 0.64, 95% CI: 0.26–1.02, p = 0.001). Furthermore, BKMR and weighted quantile sum models identified DMP as the primary risk contributor amongst the six detected DAP metabolites (weight = 0.573 for age at menopause and weight = 0.634 for reproductive lifespan). For the mixed analysis, the overall exposure to DAP metabolites was associated with delayed age at menopause. For the individual analysis, DMP exposure was associated with delayed age at menopause and longer reproductive lifespan, and DMP was identified as the major risk factor amongst the six detected DAP metabolites. Future research should prioritise DMP to further elucidate impacts of OPs exposure on female reproductive health.