Pesticides as a potential independent childhood leukemia risk factor and as a potential confounder for electromagnetic fields exposure

• Published in: Environmental research 2023-12, Vol.238, p.116899-116899, Article 116899
• Main Authors: Nguyen, A., Crespi, C.M., Vergara, X., Kheifets, L.
• Format: Article
• Language: English
• Subjects: active ingredients; California; case-control studies; childhood; Childhood leukemia; chlorpyrifos; class; confidence interval; dimethoate; exposure assessment; GIS; leukemia; Magnetic fields; mancozeb; molluscicides; odds ratio; oryzalin; oxyfluorfen; pendimethalin; permethrin; Pesticides; Plant nurseries; Powerlines; risk factors; rodenticides; satellites; spatial data
• ISSN: 0013-9351; 1096-0953
• DOI: 10.1016/j.envres.2023.116899

Both pesticides and high magnetic fields are suspected to be childhood leukemia risk factors. Pesticides are utilized at commercial plant nurseries, which sometimes occupy the areas underneath high-voltage powerlines. To evaluate whether potential pesticide exposures (intended use, chemical class, active ingredient) utilized at plant nurseries act as an independent childhood leukemia risk factor or as a confounder for proximity to, or magnetic fields exposure from, high-voltage powerlines. We conducted a state-wide records-based case-control study for California with 5788 childhood leukemia cases and 5788 controls that examined specific pesticide use, magnetic field exposures and distances to both powerlines and plant nurseries. Exposure assessment incorporated geographic information systems, aerial satellite images, and other historical information. Childhood leukemia risk was potentially elevated for several active pesticide ingredients: permethrin (odds ratio (OR) 1.49, 95% confidence interval (CI) (0.83–2.67), chlorpyrifos (OR 1.29, 95% CI 0.89–1.87), dimethoate (OR 1.79, 95% CI 0.85–3.76), mancozeb (OR 1.41, 95% CI 0.85–2.33), oxyfluorfen (OR 1.41, 95% CI 0.75–2.66), oryzalin (OR 1.60, 95% CI 0.97–2.63), and pendimethalin (OR 1.82, 95% CI 0.81–2.25). Rodenticide (OR 1.42, 95% CI 0.78–2.56) and molluscicide (OR 1.22, 95% CI 0.82–1.81) exposure also presented potentially elevated childhood leukemia risks. Childhood leukemia associations with calculated fields or powerline proximity did not materially change after adjusting for pesticide exposure. Childhood leukemia risks with powerline proximity remained similar when pesticide exposures were excluded. Pesticide exposure may be an independent childhood leukemia risk factor. Childhood leukemia risks for powerline proximity and magnetic fields exposure were not explained by pesticide exposure. •Residing close to a plant nursery may increase risk for childhood leukemia (CL)•Active ingredients in pesticides associated with childhood leukemia are identified•Pesticides do not explain observed CL and residential magnetic fields association•Pesticides do not explain observed CL and distance to powerline association