Exposure to phenoxyacetic acids and glyphosate as risk factors for non-Hodgkin lymphoma- pooled analysis of three Swedish case-control studies including the sub-type hairy cell leukemia.

The association between pesticide exposure and non-Hodgkin lymphoma (NHL) including hairy cell leukemia (HCL) was analyzed in a pooled study of three case-control studies. Results on exposure to pesticides were based on 1,425 cases and 2,157 controls participating in the studies. Exposures were assessed by self-administered questionnaires completed as needed by phone. In the pooled univariate analyses adjusted by age, gender and year of diagnosis, exposure to herbicides of the phenoxyacetic acid type yielded statistically significant increased risk with odds ratio (OR) = 1.9, 95% confidence interval CI) = 1.4-2.5. The herbicide glyphosate gave OR = 2.2, 95% CI = 1.3-3.8. Impregnating agents increased the risk. No clear dose-response effect was seen. OR was highest in the >10-20 years latency group for herbicides and impregnating agents. In the multivariate analysis including main pesticide groups, statistically significant increased risk was found for herbicides, OR = 1.6, 95% CI = 1.2-2.1 and impregnating agents with OR = 1.4, 95% CI = 1.1-1.8. This analysis confirmed an association between NHL including HCL and exposure to certain herbicides.