Pesticide Exposure and Depression among Male Private Pesticide Applicators in the Agricultural Health Study

BACKGROUND: Pesticide exposure may be positively associated with depression. Few previous studies have considered the episodic nature of depression or examined individual pesticides. OBJECTIVE: We evaluated associations between pesticide exposure and depression among male private pesticide applicators in the Agricultural Health Study. METHODS: We analyzed data for 10 pesticide classes and 50 specific pesticides used by 21,208 applicators enrolled in 1993-1997 who completed a follow-up telephone interview in 2005-2010. We divided applicators who reported a physician diagnosis of depression (n = 1,702; 8%) into those who reported a previous diagnosis of depression at enrollment but not follow-up (n = 474; 28%), at both enrollment and follow-up (n = 540; 32%), and at follow-up but not enrollment (n = 688; 40%) and used polytomous logistic regression to estimate odds ratios (ORs) and 95% CIs. We used inverse probability weighting to adjust for potential confounders and to account for the exclusion of 3,315 applicators with missing covariate data and 24,619 who did not complete the follow-up interview. RESULTS: After weighting for potential confounders, missing covariate data, and dropout, ever-use of two pesticide classes, fumigants and organochlorine insecticides, and seven individual pesticides- the fumigants aluminum phosphide and ethylene dibromide; the phenoxy herbicide (2,4,5-trichlorophenoxy) acetic acid (2,4,5-T); the organochlorine insecticide dieldrin; and the organophosphate insecticides diazinon, malathion, and parathion-were all positively associated with depression in each case group, with ORs between 1.1 and 1.9. CONCLUSIONS: Our study supports a positive association between pesticide exposure and depression, including associations with several specific pesticides.