title: Multimorbidity and Risk of Mild Cognitive Impairment.
abstract: OBJECTIVE
  To determine the association between multiple chronic conditions and risk of incident mild cognitive impairment (MCI) and dementia.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Olmsted County, Minnesota.
  
  
  METHODS
  Cognitively normal individuals (N = 2,176) enrolled in the Mayo Clinic Study of Aging (MCSA).
  
  
  METHODS
  Participants were randomly selected from the community, evaluated by a physician, and underwent neuropsychometric testing at baseline and at 15-month intervals to assess diagnoses of MCI and dementia. Information on International Classification of Diseases, Ninth Revision codes for chronic conditions in the 5 years before enrollment was electronically captured using the Rochester Epidemiology Project medical records linkage system. Multimorbidity was defined as having two or more chronic conditions, and the association between multimorbidity and MCI and dementia was examined using Cox proportional hazards models.
  
  
  RESULTS
  Of 2,176 cognitively normal participants (mean age ± standard deviation 78.5 ± 5.2; 50.6% male), 1,884 (86.6%) had multimorbidity. The risk of MCI or dementia was higher in persons with multimorbidity (hazard ratio (HR) = 1.38, 95% confidence interval (CI) = 1.05-1.82) than in those with one or no chronic condition. The HR was of greater magnitude in persons with four or more conditions (HR = 1.61, 95% CI = 1.21-2.13) than in those with two or three conditions (HR = 1.03, 95% CI = 0.76-1.39) and for men with multimorbidity(HR = 1.53, 95% CI = 1.01-2.31) than for women with multimorbidity (HR = 1.20, 95% CI = 0.83-1.74), compared to those with one or no chronic condition.
  
  
  CONCLUSIONS
  In older adults, having multiple chronic conditions is associated with greater risk of MCI and dementia. This is consistent with the hypothesis that multiple etiologies may contribute to MCI and late-life dementia. Preventing chronic diseases may be beneficial in delaying or preventing MCI and dementia.
authors: Department of Neurology, Mayo Clinic, Rochester, Minnesota.|Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Maria
authors: M
authors: Vassilaki
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Jeremiah A
authors: JA
authors: Aakre
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Ruth H
authors: RH
authors: Cha
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Walter K
authors: WK
authors: Kremers
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.|Robert D. and Patricia E. Kern Center for the Science of Healthcare Delivery, Mayo Clinic, Rochester, Minnesota.
authors: Jennifer L
authors: JL
authors: St Sauver
authors: Department of Neurology, Mayo Clinic, Rochester, Minnesota.|Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Michelle M
authors: MM
authors: Mielke
authors: Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.|Department of Psychiatry and Psychology, Mayo Clinic, Scottsdale, Arizona.|Department of Neurology, Mayo Clinic, Scottsdale, Arizona.
authors: Yonas E
authors: YE
authors: Geda
authors: Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota.
authors: Mary M
authors: MM
authors: Machulda
authors: Department of Neurology, Mayo Clinic, Rochester, Minnesota.
authors: David S
authors: DS
authors: Knopman
authors: Department of Neurology, Mayo Clinic, Rochester, Minnesota.|Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Ronald C
authors: RC
authors: Petersen
authors: Department of Neurology, Mayo Clinic, Rochester, Minnesota.|Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota.
authors: Rosebud O
authors: RO
authors: Roberts
mesh_terms: D000368:Aged; D002908:Chronic Disease / Q000453:epidemiology*; D060825:Cognitive Dysfunction / Q000453:epidemiology*; D015897:Comorbidity; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D018570:Risk Assessment
keywords: dementia; mild cognitive impairment; multimorbidity