Is a Good Sleep on Mosquito-Free Nights Worth the Risk of Lymphoma Associated with the Use of Household Insecticides? A Case-Control Study of Lymphoma Subtypes in Adults

Background. The evidence linking the use of household pesticides and the risk of lymphoma is scanty. Methods. We explored the hypothesis in a population-based case-control study on lymphoma conducted in Sardinia, Italy, in 1998-2004, including 325 cases and 465 population controls and data on lifetime frequency, seasonality, and years of use of household insecticides and potential confounders. We calculated the risk of lymphoma (all subtypes) and its major subtypes associated with using household insecticides in three time windows (up to 1978, from 1979-2001, and 2002 onwards) with unconditional logistic regression adjusting by age, sex, education, and occupational exposure to pesticides. Results. Household insecticides did not increase risk of lymphoma (all subtypes), Hodgkin's lymphoma, B-cell lymphoma, and the major B-cell lymphoma subtypes. The risk of multiple myeloma (MM) but not the other subtypes showed a non-significant upward trend (p = 0.203) with increasing quartiles of days of use in the time window when propoxur was the most popular household insecticide. Conclusions. Our results suggest no association between the household use of insecticides and the risk of lymphoma. Further studies are warranted to confirm or discard an association between MM risk and the use of propoxur.