Pesticide exposure as a risk factor for amyotrophic lateral sclerosis: A meta-analysis of epidemiological studies

Environmental and Occupational Risk Factors for Amyotrophic Lateral Sclerosis: A Case-Control Study

“…Our findings confirm results of previous research suggesting a potential relationship between exposure to metals [11,12,13,14,15,16,17] and pesticides [23,35,38,39] and risk of ALS. Although not causally related, lead has been the most consistent environmental risk factor over time [11,13,16,17].…”

“…Since the 1970s, most studies have reported an association between exposure to metals, such as lead, mercury or others, and risk of ALS [10,11,12,13,14,15,16,17], although others have failed to find a statistically significantly increased risk of disease [18,19]. The relationship between exposure to pesticides, agricultural occupations and residing in a rural area and risk of ALS has been inconsistent as only about half of the epidemiologic studies, including two meta-analyses, have found an association [14,20,21,22,23,24,25]. However, this finding has not been replicated by some studies [26,27,28,29].…”

Neuron-Microglia Interactions in Motor Neuron Degeneration. The Inflammatory Hypothesis in Amyotrophic Lateral Sclerosis Revisited

“…Until now, the higher ALS prevalence in specific groups of patients (football players [21][22][23], veterans of the Gulf War [24,25] or farmers with elevated pesticide and/or fertilizer exposure [26][27][28][29]) has not helped unravel the cascade of events or the driving force underlying the disease. Several pathological mechanisms such as genetic factors, environment, autoimmunity, oxidative stress, excitotoxicity, microglial activation, impairment in filament organization and neuronal transport, and misfolded proteins have been proposed as possible explanations of ALS heterogeneity [30,31].…”

Amyotrophic lateral sclerosis and environmental factors

“…Another prospective study (Weisskopf et al, 2009), which assessed ALS risk and pesticide exposure in a large cohort, detected only a slight but not statistically significant increased ALS risk. The hypothesis of a relationship between pesticides and motor neuron diseases is also supported by other case-control studies (Bonvicini et al, 2010;Malek et al, 2012;Pamphlett, 2012). A systematic review of the MEDLINE, EMBASE, CINAHL and Cochrane databases up to March 2007 found that seven out of 37 studies dealing with chemicals and pesticides had sufficient methodological and exposure assessment quality.…”

“…Nevertheless, on the basis of the cohort study data it was concluded that evidence suggesting an involvement of these chemical compounds in ALS pathogenesis was present, but not statistically significant. A more recent meta-analysis (Malek et al, 2012), which evaluated 1,517 ALS deaths reported in a retrospective cohort study and 589 ALS cases reported in five case-control studies, and calculated the sex-specific pooled ORs, found a pesticides-related increased risk of ALS for male cases (OR 1.88). A recent meta-analysis study, which analyzed 750 publications from 1980 up to April 2013, found an association between ALS and pesticides only in men, with a dose-response relationship (Capozzella et al, 2014).…”