Pesticide exposure assessed through agricultural crop proximity and risk of amyotrophic lateral sclerosis

Abstract

BackgroundEpidemiologic studies have raised the possibility that some pesticide compounds induce the neurodegenerative disease amyotrophic lateral sclerosis (ALS), though the available evidence is not entirely consistent.MethodsWe conducted a population-based case-control study in two Italian populations to assess the extent to which residence in the vicinity of agricultural crops associated with the application of neurotoxic pesticides is a risk factor for ALS, using crop acreage in proximity to the residence as an index of exposure.ResultsBased on 703 cases and 2737 controls, we computed an ALS odds ratio of 0.92 (95% confidence interval 0.78-1.09) for those in proximity to agricultural land. Results were not substantially different when using alternative exposure categories or when analyzing specific crop types, with the exception of a higher risk related to exposure to citrus orchards and olive groves in Southern Italy, though based on few exposed subjects (N = 89 and 8, respectively). There was little evidence of any dose-response relation between crop proximity and ALS risk, and using long-term residence instead of current residence did not substantially change our estimates.ConclusionsThough our index of exposure is indirect and subject to considerable misclassification, our results offer little support for the hypothesis that neurotoxic pesticide exposure increases ALS risk.

Environmental and Occupational Risk Factors of Amyotrophic Lateral Sclerosis: A Population-Based Case-Control Study

“…Conversely, residential use of pesticides showed no such association in our study with ALS risk, with reference either to the use of pesticides for plants or to their use for bugs and other animals. We have previously found similar substantial inconclusive findings when we evaluated residential exposure to pesticides based on crop proximity of the house of the subjects, except for an imprecise increase for citrus orchards in the Sicily region [34].…”

Atmospheric Dispersion Modelling and Spatial Analysis to Evaluate Population Exposure to Pesticides from Farming Processes

“…The discussion of the results obtained by the proximity model from the epidemiological point of view for this case study was presented in literature by Vinceti et al [47]. Future outlooks include the use of the exposure scenario evaluated by CAREA in the aforementioned study.…”

“…The reference population of 2584 people used as target receptors for the assessment of the exposure to pesticides is composed by newly diagnosed ALS cases and up to four age-and sex-matched controls randomly selected from the resident population of the three provinces [47]. Spatially distribution of receptors over the study area is featured by fewer counts in the Southern mountainous part of the area and higher numbers in the surroundings of the main city centres, characterized by a higher population density.…”

“…Here, receptors with exposure equal to 0 were defined as not-exposed. The discussion of the results obtained by the proximity model from the epidemiological point of view for this case study was presented by Vinceti et al [47]. The CAREA output provided, for each receptor, a relative concentration value (C) assumed proportional to the receptor exposure to orchards and the concentration ratio (Ĉ), which is a normalization of the concentration of the receptor according to a reference case.…”

Genetic polymorphisms in amyotrophic lateral sclerosis: Evidence for implication in detoxification pathways of environmental toxicants

“…A few studies, with a variety in design (case-control, cohort, perspective, meta-analysis and systematic reviews) have demonstrated an association between ALS and pesticides, heavy metals, mercury and xenobiotics (Bozzoni et al, 2016;Capozzella et al, 2014;Deziel et al, 2015;Gibb and O'Leary, 2014;Krewski et al, 2017;Yu et al, 2014). However, there are also studies that have failed to reveal any association (Capozzella et al, 2014;Vinceti et al, 2017a;Vinceti et al, 2017b;Yu et al, 2014). The review by Bozzoni et al concluded that there is strong evidence that pesticides have a crucial role in ALS development and that they are significant risk factors for neurodegeneration (Bozzoni et al, 2016).…”