title: Associations of Midlife to Late Life Fatigue With Physical Performance and Strength in Early Old Age: Results From a British Prospective Cohort Study.
abstract: OBJECTIVE
  To examine associations of fatigue in midlife and later life with physical performance and strength in early old age.
  
  
  METHODS
  Data on approximately 1800 men and women from the UK Medical Research Council National Survey of Health and Development with data on fatigue at ages 43 and 60 to 64 years were used. Fatigue was defined as perceived tiredness and was assessed prospectively at ages 43 and 60 to 64 years. At both ages, participants were categorized as having no, occasional, or frequent fatigue. Physical performance and strength were measured at age 60 to 64 years using four objective measures: grip strength, standing balance, chair rising, and timed get-up-and-go (TUG) tests.
  
  
  RESULTS
  There were associations between reports of frequent fatigue at both ages and poorer grip strength, chair rise, and TUG performance at 60 to 64 years. Furthermore, individuals reporting frequent fatigue at both ages had weaker grip strength (β = -4.09 kg, 95% confidence interval [CI] = -6.71 to -1.48) and slower chair rise (β = -4.65 repetitions/min, 95% CI = -6.65 to -2.64) and TUG (β = -4.22 cm/s, 95% CI = -12.16 to -2.28) speeds when compared with those who reported no fatigue at both time points. These associations were robust and were maintained after adjustment for a range of covariates including physical activity and health status.
  
  
  CONCLUSIONS
  Reports of frequent fatigue were associated with poorer physical performance in early old age, especially if sustained from midlife to later life. These findings indicate that it is not just fatigue but fatigue sustained across adulthood that has implications for later life functioning.
authors.affiliation: From the Section of Social Medicine (Mänty), Department of Public Health, and Center for Healthy Aging (Mänty), University of Copenhagen, Copenhagen, Denmark; Department of Public Health (Mänty), University of Helsinki, Helsinki, Finland; MRC Unit for Lifelong Health and Ageing at UCL (Kuh, Cooper), London, UK.
authors.forename: Minna
authors.initials: M
authors.lastname: Mänty
authors.forename: Diana
authors.initials: D
authors.lastname: Kuh
authors.forename: Rachel
authors.initials: R
authors.lastname: Cooper
mesh_terms: D000328:Adult; D000367:Age Factors; D000375:Aging / Q000502:physiology*; D005080:Exercise Test; D005221:Fatigue / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology*; D011446:Prospective Studies; D006113:United Kingdom