Pesticide Use and Age-Related Macular Degeneration in the Agricultural Health Study

BACKGROUND: Age-related macular degeneration (AMD) is a leading cause of blindness in developed countries. Few studies have investigated its relationship to environmental ncurotoxicants. In previous cross-sectional studies, we found an association between pesticide use and self-reported retinal degeneration. OBJECTIVE: We evaluated the association of pesticide use with physician-confirmed incident AWL. METHODS: The Agricultural Health Study (AHS) is a prospective cohort of pesticide applicators and their spouses enrolled from 1993-1997 in Iowa and North Carolina. Cohort members reported lifetime use of 50 specific pesticides at enrollment. Self-reports of incident AMD during follow-up through 2007 were confirmed by reports from participants' physicians and by independent evaluation of retinal photographs provided by the physicians. Confirmed cases (n = 161) were compared with AHS cohort members without AMD in = 39,108). We estimated odds ratios (ORS) and 95% confidence intervals (Cis) by logistic regression with adjustment for age, gender, and smoking. RESULTS: AMD was associated with ever use of organochlorine [OR = 2.7 (95% CI: 1.8,4.0)1 and organophosphate [OR =2.0 (95% CI: 1.3, 3.0)1 insecticides and phenoxyacetate herbicides [OR = 1.9 (95% CL 1.2, 2.8)]. Specific pesticides consistently associated with AMD included chlordane, dichlorodiphenyltrichloroethane (DDT), malathion, and captan; others with notable but slightly less consistent associations were heptachlor, diazinon, phorate, 2,4,5-aichlorophenoxyacetic acid (2,4,5-T), and 2,4-dichlorophenoxyacetic acid (2,4-D). Results were similar for men and women. Some specific pesticides were associated with both early- and late-stage AMD, but others were associated with only one stage. CONCLUSIONS: Exposures to specilic pesticides may be modifiable risk factors for AMD.