Identification of Risk Factors Associated with Aetiology of Amyotrophic Lateral Sclerosis Based on Systematic Review and Meta-Analysis

• Main Author: Wang, Ming-Dong
• Other Authors: Krewski, Daniel
• Language: en
• Published: Université d'Ottawa / University of Ottawa 2014
• Subjects: Amyotrophic lateral sclerosis; Motor neuron disease; Risk factor; Heavy metal; Pesticide; Trauma; Injury; Solvent; Electric shock; Smoking; Ataxin-2; Systematic review; Meta-analysis; Genetic factor; Progression; Aetiology
• Online Access: http://hdl.handle.net/10393/31145; http://dx.doi.org/10.20381/ruor-3755

To identify the risk factors being associated with aetiology of amyotrophic lateral sclerosis (ALS), a series of systematic reviews based on existing observational epidemiological studies identified through searching of bibliographic databases were conducted. Associations between ALS and a number of genetic and environmental risk factors were examined using meta-analysis. Specifically we found that previous exposure to lead, pesticides, solvents, experience of trauma and electric shock were associated with relative increased risks of developing ALS of 86% [odds ratio (OR) =1.86, 95% CI: 1.39-2.48], 57% (OR=1.57,95% CI: 1.19-2.08), 47% (OR=1.47, 95%CI: 1.13-1.80), 64% (OR=1.64; 95%CI: 1.36-1.98), and 2.27% (OR=3.27, 95%CI:1.87-5.73) respectively, compared to their corresponding controls. The presence of intermediate CAG repeat expansion in the ATXN2 gene was associated with a 4.4 -fold increase in the risk of ALS (OR=4.44, 95%CI: 2.91-6.76). However, the attributable risk associated with each identified risk factor was estimated to be less than 5% of all ALS cases. These results confirm that ALS is a rare multifactorial degenerative condition of motor-neurons.