Health researchers have been unable to explain why several studies have found an excess risk of melanoma and other skin cancer for farmers. Farmers spend time in the sun — which is a major risk factor — but could it be something else? New research suggests that exposure to certain pesticides could be one of the causes. Epidemiologists from the University of Iowa, NIH and the National Cancer Institute used data collected from a group of licensed pesticide applicators in Iowa and North Carolina to determine if melanoma incidence was correlated with the use of any of 50 pesticides. After correcting for typical melanoma health risks and other factors (following standard epidemiological protocol), they found increased risks for those exposed to maneb/mancozeb, parathion and carbaryl (see note below for risk details). (Environmental Health Perspectives)
The study's results are another reminder that although lists of pesticide residues like EWG's Dirty Dozen/Clean Fifteen can help consumers avoid pesticides, the effects of pesticides are felt far and wide. A newsletter from San Francisco-based CUESA eloquently examined this issue.
Note: for maneb/mancozeb, the odds ratio was 2.4 (i.e., the rate of melanoma for the study group was 2.4 times higher than the general population), with a 95% confidence interval of 1.2-4.9 for 63+ exposure days. For parathion, the odds ratio was 2.4, 95% confidence interval of 1.3-4.4 for 56+ exposure days. For carbaryl, the odds ratio was 1.7, 95% confidence interval of 1.1-2.5 for 56+ exposure days.