Association between exposure to organophosphorus pesticide and suicidal ideation among U.S. adults: A population-based study

Objective: This study aims to investigate the potential link between exposure to organophosphorus pesticides (OPPs) and suicidal ideation (SI) among adults.

Methods: This study encompassed four cycles of the National Health and Nutrition Examination Survey (NHANES), involving 5244 participants aged 20 and above. SI was assessed using the Patient Health Questionnaire-9. The levels of exposure to OPPs were estimated by analyzing concentrations of OPP metabolites in urine samples. Multivariate logistic regression models were used to explore the association between exposure to each OPP and SI. Stratified analyses and interaction tests were conducted across various groups, including pairwise combinations of gender and age, as well as body mass index, smoking status, hypertension, and diabetes. Weighted Quantile Sum (WQS) regression and Bayesian Kernel Machine Regression (BKMR) models were applied to assess the cumulative impact of exposure to the four OPPs on SI, along with their respective contributions. Additionally, the potential interactions among these four OPPs were evaluated.

Results: Multivariate logistic regression revealed that only dimethylthiophosphate (DMTP) among OPPs demonstrated a statistically significant positive association with SI [OR: 1.18; 95 % CI: 1.02-1.37]. Stratified analyses indicated that the influence of OPPs on SI was particularly pronounced in young and older men. The WQS regression analysis revealed a statistically significant association between the mixed metabolites of OPPs and SI [OR = 1.10, 95 % CI: 1.04-1.16], with DMTP (weighted 0.63) contributing the most. Furthermore, the BKMR model supported a positive trend in the overall impact of these OPP metabolites on SI, displaying notable individual exposure-response relationships for DMTP (PIP: 0.77).

Conclusions: Our study suggests an association between exposure to DMTP and an increased risk of SI. Specifically, young adult males and older males appear particularly susceptible to the effects of OPP exposure.