Pesticide exposure and lung cancer risk: A case-control study in Nakhon Sawan, Thailand

Abstract

Background: Pesticide exposure might increase risk of lung cancer. The purpose of this study was to investigate the association between the historical use of pesticides and lung cancer using a case-control design. Methods: This case-control study compared a lifetime pesticide exposure of 233 lung cancer cases, and 447 healthy neighbours matched for gender, and age (±5 years). Data on demographic, pesticide exposure and other related factors were collected using a face-to-face interview questionnaire. Associations between lung cancer and types of pesticides as well as individual pesticides were analysed using logistic regression adjusted for gender, age, cigarette smoking, occupation, cooking fumes exposure, and exposure to air pollution. Results: It was found that lung cancer was positively associated with lifetime use of herbicides and insecticides. Compared to people in the non-exposed groups, those in Q3-Q4 days of using herbicides and insecticides had an elevated risk of lung cancer, with odds ratio (OR) between 2.20 (95% confidence interval (CI) 1.24-3.89), and 3.99 (95% CI 1.62-7.11) (p < 0.001). For individual pesticides, those presenting a significant association with lung cancer were dieldrin (OR = 2.56; 95% CI 1.36-4.81), chlorpyrifos (OR = 3.29; 95 % CI 1.93-5.61), and carbofuran (OR = 2.10; 95% CI 1.28-3.42). It was also found, for the first time, carbofuran, glyphosate, and paraquat to be significantly associated with lung cancer. Conclusions: The results reconfirmed the association between pesticides exposure and lung cancer. In the study, five individual pesticides, e.g. dieldrin, chlorpyrifos, carbofuran, glyphosate, and paraquat were identified as a potential risk factors for the disease. More studies are still required to confirm the results and to identify more individual pesticides that could cause lung cancer. The issues should receive more attention since these chemicals are used widely.