title: Independent and combined effects of cognitive and physical activity on incident MCI.
abstract: BACKGROUND
  The objective of this study was to examine the independent and combined influences of late-life cognitive activity (CA) and physical activity (PA) on the risk of incident mild cognitive impairment (MCI).
  
  
  METHODS
  We used interval censored survival modeling to examine the risk of incident MCI (Clinical Dementia Rating [CDR] = 0.5) as a function of CA (high vs. low) and at least moderate intensity PA (any vs. none) among 864 cognitively normal (CDR = 0) older adults.
  
  
  RESULTS
  During three annual follow-up waves, 72 participants developed MCI. Compared with low CA with no PA, significant reductions in risk for MCI were observed for high CA with any PA (hazards ratio (HR) = 0.20, 95% confidence interval (CI) 0.07-0.52) and low CA with any PA (HR = 0.52, 95% CI 0.29-0.93), but not for high CA without PA (HR = 0.94, 95% CI 0.45-1.95).
  
  
  CONCLUSIONS
  These findings suggest that a combination of CA and PA may be most efficacious at reducing the risk for cognitive impairment.
authors: Department of Psychiatry, University of Pittsburgh, Pittsburgh PA, USA. Electronic address: hughest2@upmc.edu.
authors: Tiffany F
authors: TF
authors: Hughes
authors: Department of Psychiatry, University of Pittsburgh, Pittsburgh PA, USA; Department of Neurology, University of Pittsburgh, Pittsburgh PA, USA; Department of Psychology, University of Pittsburgh, Pittsburgh PA, USA.
authors: James T
authors: JT
authors: Becker
authors: Department of Psychiatry, University of Pittsburgh, Pittsburgh PA, USA.
authors: Ching-Wen
authors: CW
authors: Lee
authors: Department of Medicine, University of Pittsburgh, Pittsburgh PA, USA; Department of Biostatistics, University of Pittsburgh, Pittsburgh PA, USA.
authors: Chung-Chou H
authors: CC
authors: Chang
authors: Department of Psychiatry, University of Pittsburgh, Pittsburgh PA, USA; Department of Neurology, University of Pittsburgh, Pittsburgh PA, USA; Department of Epidemiology, University of Pittsburgh, Pittsburgh PA, USA.
authors: Mary
authors: M
authors: Ganguli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003071:Cognition; D060825:Cognitive Dysfunction / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008609:Mental Status Schedule; D009043:Motor Activity; D010414:Pennsylvania / Q000453:epidemiology; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D016019:Survival Analysis
keywords: Cognitive activity; Cohort study; Epidemiology; Mild cognitive impairment; Physical activity; observational study