title: Associations between Physical Activity in Old Age and Dementia-Related Mortality: A Population-Based Cohort Study.
abstract: BACKGROUND
  Findings from the literature vary in relation to whether physical activity brings about less cognitive decline in old age. The present study investigated self-reported levels of physical activity in old age and its association with the risk of dementia-related mortality.
  
  
  METHODS
  We included data from 31,086 subjects, between 65 and 80 years old, from the CONOR (Cohort of Norway) database. Cox regression analysis was used to estimate the risk of association.
  
  
  RESULTS
  Taking part in 'light' (not causing perspiration or panting) activities of <3 h per week was associated with a decreased risk of dementia-related mortality, with a hazard ratio (HR) of 0.74 and a 95% confidence interval (CI) of 0.62-0.88, and of >3 h per week, with an HR of 0.61 and a 95% CI of 0.51-0.73. When taking part in 'hard' (causing perspiration or panting) activities, a similar risk (HR = 0.56; 95% CI 0.43-0.72) was observed for >3 h per week. Interestingly, the highest reduction in risk was seen for 'hard' activities of <3 h per week (HR = 0.50; 95% CI 0.41-0.61).
  
  
  CONCLUSIONS
  Physical activity during leisure time in old age was associated with a lower risk of dementia-related mortality when compared to inactive individuals.
authors.affiliation: Institute of Health and Society, University of Oslo, Norway.
authors.forename: Tor Atle
authors.initials: TA
authors.lastname: Rosness
authors.affiliation: Institute of Health and Society, University of Oslo, Norway ; Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Bjørn Heine
authors.initials: BH
authors.lastname: Strand
authors.affiliation: Department of Geriatric Psychiatry, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Astrid Liv Mina
authors.initials: AL
authors.lastname: Bergem
authors.affiliation: Norwegian Centre for Ageing and Health, Vestfold Health Trust, Tønsberg, Norway.
authors.forename: Knut
authors.initials: K
authors.lastname: Engedal
authors.affiliation: Institute of Health and Society, University of Oslo, Norway.
authors.forename: Espen
authors.initials: E
authors.lastname: Bjertness
keywords: Dementia; Epidemiology; Geriatric medicine; Longitudinal studies; Physical activity