title: Military Service and Amyotrophic Lateral Sclerosis in a Population-based Cohort.
abstract: BACKGROUND
  Military service has been suggested to be associated with an increased risk of amyotrophic lateral sclerosis (ALS), but only one prospective study-of a volunteer cohort-has examined this question.
  
  
  METHODS
  We prospectively assessed the relation between service in the military and ALS mortality among participants in the National Longitudinal Mortality Study, a population-representative cohort of U.S. men and women surveyed from 1973 through 2002. Participant follow-up was conducted from 1979 through 2002 for ALS mortality. There were 696,743 men and 392,571 women who were 25 years old or more with military service data. In this group, there were 375 male ALS deaths and 96 female ALS deaths. Adjusted hazard ratios (HRs) were calculated using Cox proportional hazards.
  
  
  RESULTS
  Men who served in the military had an increased adjusted ALS death rate [HR: 1.23; 95% confidence interval (CI): 0.98, 1.53] compared with those who did not serve. An increase in ALS mortality was found among those who served during World War II (HR: 1.47; 95% CI: 1.13, 1.91) but not during other time periods. This pattern of results was similar for women, but with larger confidence intervals (HR for military service: 1.26; 95% CI: 0.29, 5.59; HR for service during World War II: 2.03; 95% CI: 0.45, 9.05).
  
  
  CONCLUSIONS
  Military personnel have an increased risk of ALS, which may be specific to certain service periods although there was no data on actual deployment. Because of the longer follow-up time for World War II veterans, we cannot rule out that increased risk for those who served during other periods would be seen with further follow-up.
authors.affiliation: From the aDepartment of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA; bDepartment of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA; cDepartment of Neurology, Massachusetts General Hospital, Boston, MA; and dCenter for Administrative Records and Applications, US Bureau of the Census, Washington, DC.
authors.forename: Marc G
authors.initials: MG
authors.lastname: Weisskopf
authors.forename: Merit E
authors.initials: ME
authors.lastname: Cudkowicz
authors.forename: Norman
authors.initials: N
authors.lastname: Johnson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000453:epidemiology / Q000401:mortality*; D015331:Cohort Studies; D004781:Environmental Exposure / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008889:Military Personnel / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D014481:United States / Q000453:epidemiology; D047789:World War II