title: Self-reported fatigue and physical function in late mid-life.
abstract: OBJECTIVE
  To determine the association between the 5 subscales of the Multidimensional Fatigue Inventory (MFI-20) and physical function in late mid-life.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  A population-based sample of adults who participated in the Copenhagen Aging and Midlife Biobank population cohort (n = 4,964; age 49-63 years).
  
  
  METHODS
  Self-reported fatigue was measured using the MFI-20 comprising: general fatigue, physical fatigue, reduced activity, reduced motivation, and mental fatigue. Handgrip strength and chair rise tests were used as measures of physical function. Multiple logistic regression analyses were used to determine the associations between handgrip strength and the chair rise test with the MFI-20 subscales, adjusted for potential confounders.
  
  
  RESULTS
  After adjustments for potential confounders, handgrip strength was associated with physical fatigue (adjusted odds ratio (OR) 0.75 (95% confidence interval (CI) 0.66-0.86); p ≤ 0.001) and reduced motivation (adjusted OR 0.85 (95% CI 0.75-0.96); p ≤ 0.05), but not with the other subscales. After these adjustments, the chair rise test was associated with physical fatigue (adjusted OR 0.61 (0.53-0.69); p ≤ 0.001), general fatigue (adjusted OR 0.72 (0.62-0.84); p ≤ 0.001), reduced activity (adjusted OR 0.79 (0.70-0.90); p ≤ 0.001) and reduced motivation (adjusted OR 0.84 (0.74-0.95); p ≤ 0.01), but not with mental fatigue. Subgroup analyses for sex did not show statistically significant different associations between physical function and fatigue.
  
  
  CONCLUSIONS
  The present study supports the physiological basis of 4 subscales of the MFI-20. The association between fatigue and function was independent of gender.
authors.affiliation: University of Groningen, The Netherlands, University of Groningen, The Netherlands.
authors.forename: Han
authors.initials: H
authors.lastname: Boter
authors.forename: Minna
authors.initials: M
authors.lastname: Mänty
authors.forename: Ase Marie
authors.initials: AM
authors.lastname: Hansen
authors.forename: Tibor
authors.initials: T
authors.lastname: Hortobágyi
authors.forename: Kirsten
authors.initials: K
authors.lastname: Avlund
mesh_terms: D018070:Biological Specimen Banks; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000503:physiopathology* / Q000534:rehabilitation; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D005222:Mental Fatigue / Q000503:physiopathology / Q000534:rehabilitation; D008875:Middle Aged; D057566:Self Report