title: A meta-analysis of observational studies of the association between chronic occupational exposure to lead and amyotrophic lateral sclerosis.
abstract: OBJECTIVE
  The association between occupational exposure to lead and amyotrophic lateral sclerosis (ALS) was examined through systematic review and meta-analyses of relevant epidemiological studies and reported according to PRISMA guidelines.
  
  
  METHODS
  Relevant studies were searched in multiple bibliographic databases through September 2013; additional articles were tracked through PubMed until submission. All records were screened in DistillerSR, and the data extracted from included articles were synthesized with meta-analysis.
  
  
  RESULTS
  The risk of developing ALS among individuals with a history of exposure to lead was almost doubled (odds ratio, 1.81; 95% confidence interval, 1.39 to 2.36) on the basis of nine included case-control studies with specific lead exposure information, with no apparent heterogeneity across included studies (I = 14%). The attributable risk of ALS because of exposure to lead was estimated to be 5%.
  
  
  CONCLUSIONS
  Previous exposure to lead may be a risk factor for ALS.
authors.affiliation: From the Department of Epidemiology and Community Medicine (Drs Wang, Gomes, Little, and Krewski), Faculty of Medicine, University of Ottawa, Ontario; and Department of Medicine (Dr Cashman), University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Ming-Dong
authors.initials: MD
authors.lastname: Wang
authors.forename: James
authors.initials: J
authors.lastname: Gomes
authors.forename: Neil R
authors.initials: NR
authors.lastname: Cashman
authors.forename: Julian
authors.initials: J
authors.lastname: Little
authors.forename: Daniel
authors.initials: D
authors.lastname: Krewski
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D007854:Lead / Q000633:toxicity*; D064887:Observational Studies as Topic; D016273:Occupational Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D012307:Risk Factors
chemical_list: D007854:Lead