title: Association between late-life social activity and motor decline in older adults.
abstract: BACKGROUND
  Loss of motor function is a common consequence of aging, but little is known about the factors that predict idiopathic motor decline. Our objective was to test the hypothesis that late-life social activity is related to the rate of change in motor function in old age.
  
  
  METHODS
  Longitudinal cohort study with a mean follow-up of 4.9 years with 906 persons without stroke, Parkinson disease, or dementia participating in the Rush Memory and Aging Project. At baseline, participants rated the frequency of their current participation in common social activities from which a summary measure of social activity was derived. The main outcome measure was annual change in a composite measure of global motor function, based on 9 measures of muscle strength and 9 motor performances.
  
  
  RESULTS
  Mean (SD) social activity score at baseline was 2.6 (0.58), with higher scores indicating more frequent participation in social activities. In a generalized estimating equation model, controlling for age, sex, and education, global motor function declined by approximately 0.05 U/y (estimate, 0.016; 95% confidence interval [CI], -0.057 to 0.041 [P = .02]). Each 1-point decrease in social activity was associated with approximately a 33% more rapid rate of decline in motor function (estimate, 0.016; 95% CI, 0.003 to 0.029 [P = .02]). The effect of each 1-point decrease in the social activity score at baseline on the rate of change in global motor function was the same as being approximately 5 years older at baseline (age estimate, -0.003; 95% CI, -0.004 to -0.002 [P<.001]). Furthermore, this amount of motor decline per year was associated with a more than 40% increased risk of death (hazard ratio, 1.44; 95% CI, 1.30 to 1.60) and a 65% increased risk of incident Katz disability (hazard ratio, 1.65; 95% CI, 1.48 to 1.83). The association of social activity with the rate of global motor decline did not vary along demographic lines and was unchanged (estimate, 0.025; 95% CI, 0.005 to 0.045 [P = .01]) after controlling for potential confounders including late-life physical and cognitive activity, disability, global cognition depressive symptoms, body composition, and chronic medical conditions.
  
  
  CONCLUSIONS
  Less frequent participation in social activities is associated with a more rapid rate of motor function decline in old age.
authors: Departments of Neurological Sciences, Rush Alzheimer's Disease Center, Rush University Medical Center, Armour Academic Facility, Chicago, IL 60612, USA. Aron_S_Buchman@rush.edu
authors: Aron S
authors: AS
authors: Buchman
authors: Patricia A
authors: PA
authors: Boyle
authors: Robert S
authors: RS
authors: Wilson
authors: Debra A
authors: DA
authors: Fleischman
authors: Sue
authors: S
authors: Leurgans
authors: David A
authors: DA
authors: Bennett
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003071:Cognition / Q000502:physiology; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D007087:Illinois; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology; D012917:Social Adjustment; D013997:Time Factors