title: Spatial analysis of amyotrophic lateral sclerosis in Northern New England, USA, 1997-2009.
abstract: BACKGROUND
  An environmental trigger of sporadic amyotrophic lateral sclerosis (ALS) is supported by geographic disparities in ALS incidence and development of the disease in conjugal couples. This study aims to investigate the incidence of ALS in the Northern New England states of New Hampshire (NH), Vermont (VT), and Maine (ME).
  
  
  METHODS
  We reviewed medical records and community databases to identify dwelling addresses of 688 patients diagnosed with ALS in 1997-2009 in NH, VT, and ME. We used spatial analysis to identify clusters of census block groups with statistically significant high incidence.
  
  
  RESULTS
  We identified 11 clusters of statistically significant high incidence, each containing 6 or more cases of ALS. These 11 clusters are grouped in 4 distinct regions.
  
  
  CONCLUSIONS
  There appear to be areas of significant spatial clustering within Northern New England. Further analysis will be needed to confirm whether there is any correlation between these areas and potential environmental risk factors.
authors.affiliation: Department of Neurology, Dartmouth-Hitchcock Medical Center, 1 Medical Center Drive, Lebanon, New Hampshire 03753, USA. tracie.a.caller@hitchcock.org
authors.forename: Tracie A
authors.initials: TA
authors.lastname: Caller
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Chipman
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Field
authors.forename: Elijah W
authors.initials: EW
authors.lastname: Stommel
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000453:epidemiology*; D006801:Humans; D009511:New England; D012189:Retrospective Studies; D062206:Spatial Analysis; D014481:United States
keywords: ALS; United States; disease clusters; epidemiology; incidence; spatial analysis