Background: Melanoma rates continue to increase; however, few risk factors other than sun sensitivity and ultraviolet radiation (including sun exposure) have been identified. Although studies of farmers have shown an excess risk of melanoma and other skin cancers, it is unclear how much of this is related to sun exposure compared with other agricultural exposures.
Methods: We examined dose-response relationships for 50 agricultural pesticides and cutaneous melanoma incidence in the Agricultural Health Study cohort of licensed pesticide applicators, along with ever use of older pesticides that contain arsenic. Logistic regression was used to examine odds ratios (ORs) and 95% confidence intervals (CIs) associated with pesticide exposure adjusted for age, sex, and other potential confounders.
Results: We found significant associations between cutaneous melanoma and maneb/mancozeb (>or= 63 exposure days: OR = 2.4; 95% CI, 1.2-4.9; trend p = 0.006), parathion (>or= 56 exposure days: OR = 2.4; 95% CI, 1.3-4.4; trend p = 0.003), and carbaryl (>or= 56 exposure days: OR = 1.7; 95% CI, 1.1-2.5; trend p = 0.013). Other associations with benomyl and ever use of arsenical pesticides were also suggested.
Conclusions: Most previous melanoma literature has focused on host factors and sun exposure. Our research shows an association between several pesticides and melanoma, providing support for the hypotheses that agricultural chemicals may be another important source of melanoma risk.