title: Mortality in mild cognitive impairment varies by subtype, sex, and lifestyle factors: the Mayo Clinic Study of Aging.
abstract: BACKGROUND
  Etiologic differences in mild cognitive impairment (MCI) subtypes may impact mortality.
  
  
  OBJECTIVE
  To assess the rate of death in MCI overall, and by subtype, in the population-based Mayo Clinic Study of Aging.
  
  
  METHODS
  Participants aged 70-89 years at enrollment were clinically evaluated at baseline and 15-month intervals to assess diagnoses of MCI and dementia. Mortality in MCI cases versus cognitively normal (CN) individuals was estimated using Cox proportional hazards models.
  
  
  RESULTS
  Over a median follow-up of 5.8 years, 331 of 862 (38.4%) MCI cases and 224 of 1,292 (17.3%) cognitively normal participants died. Compared to CN individuals, mortality was elevated in persons with MCI (hazard ratio [HR] = 1.79; 95% CI: 1.41 to 2.27), and was higher for non-amnestic MCI (naMCI; HR = 2.40; 95% CI: 1.72 to 3.36) than for amnestic MCI (aMCI; HR = 1.61; 95% CI: 1.25 to 2.09) after adjusting for confounders. Mortality varied significantly by sex, education, history of heart disease, and engaging in moderate physical exercise (p for interaction <0.05 for all). Mortality rate estimates were highest in MCI cases who were men, did not exercise, had heart disease, and had higher education versus CN without these factors, and for naMCI cases versus aMCI cases without these factors.
  
  
  CONCLUSIONS
  These findings suggest stronger impact of etiologic factors on naMCI mortality. Prevention of heart disease, exercise vigilance, may reduce MCI mortality and delayed MCI diagnosis in persons with higher education impacts mortality.
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Vassilaki
authors.affiliation: Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Ruth H
authors.initials: RH
authors.lastname: Cha
authors.forename: Jeremiah A
authors.initials: JA
authors.lastname: Aakre
authors.forename: Terry M
authors.initials: TM
authors.lastname: Therneau
authors.affiliation: Department of Psychiatry and Psychology, Mayo Clinic, Scottsdale, Arizona, USA Department of Neurology, Mayo Clinic, Scottsdale, Arizona, USA.
authors.forename: Yonas E
authors.initials: YE
authors.lastname: Geda
authors.affiliation: Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Mielke
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Knopman
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Petersen
authors.affiliation: Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Rosebud O
authors.initials: RO
authors.lastname: Roberts
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000175:diagnosis / Q000209:etiology / Q000401:mortality*; D004522:Educational Status; D015444:Exercise; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000453:epidemiology; D006801:Humans; D053208:Kaplan-Meier Estimate; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D008910:Minnesota / Q000453:epidemiology; D009483:Neuropsychological Tests; D016016:Proportional Hazards Models; D012737:Sex Factors
keywords: Cohort studies; incidence studies; mild cognitive impairment; mortality; outcomes research; prognosis