title: Effect of reproductive factors and postmenopausal hormone use on the risk of amyotrophic lateral sclerosis.
abstract: OBJECTIVE
  To examine the associations of reproductive factors and postmenopausal hormone use with the risk of amyotrophic lateral sclerosis (ALS) among women.
  
  
  METHODS
  This case-control study was conducted within the Kaiser Permanente Medical Care Program (KPMCP) of Northern California during the years 1996-2000. Among the 193 postmenopausal women, 62 were incident ALS cases and 131 were controls randomly selected from KPMCP members and frequency matched by age and respondent type (self versus proxy) to the cases. Statistical analyses were carried out using logistic regression.
  
  
  RESULTS
  Reproductive factors such as age at menarche, age at final menstrual period, parity, oral contraceptive use, and type of menopause (natural vs. hysterectomy with or without oophorectomy) were not associated with risk of ALS. Postmenopausal hormone use was positively, but not significantly, associated with the risk of ALS (adjusted OR 1.9, 95% CI 0.9-3.8).
  
  
  CONCLUSIONS
  Reproductive factors were not associated with ALS risk. There is no evidence that suggests a protective effect of postmenopausal hormone use against the development of ALS. However, due to insufficient power, we cannot rule out a possible increase in ALS risk associated with postmenopausal hormone use.
authors.affiliation: Department of Health Research and Policy, Division of Epidemiology, Stanford University School of Medicine, Stanford, Calif, USA. rpopat@stanford.edu
authors.forename: Rita A
authors.initials: RA
authors.lastname: Popat
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Van Den Eeden
authors.forename: Caroline M
authors.initials: CM
authors.lastname: Tanner
authors.forename: Allan L
authors.initials: AL
authors.lastname: Bernstein
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Bloch
authors.forename: Amethyst
authors.initials: A
authors.lastname: Leimpeter
authors.forename: Valerie
authors.initials: V
authors.lastname: McGuire
authors.forename: Lorene M
authors.initials: LM
authors.lastname: Nelson
mesh_terms: D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000453:epidemiology*; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D015914:Estrogen Replacement Therapy; D005260:Female; D006801:Humans; D007044:Hysterectomy; D016017:Odds Ratio; D017584:Reproductive History; D012307:Risk Factors