Among older adults, less frequent participation in social activities is associated with a more rapid rate of motor function decline; however, little is known about factors that predict idiopathic motor decline. A recent study investigated whether late-life social activity is related to the rate of change in motor function (Arch Intern Med 2009;169:1139–46).   

The authors studied 906 older adults participating in the longitudinal Rush Memory and Aging Project (average follow-up 4.9 years). Researchers evaluated participants’ motor function by measuring grip and pinch strength; ability to stand on one leg and then on the toes; to walk in line in a heel-to-toe manner; place pegs on a board in 30 seconds; and tap index fingers for 10 seconds bilaterally. Participants completed a health survey to assess their physical activities and used a five-point rating scale to measure frequency of social activity participation. 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.  

Mean (SD) social activity score at baseline was 2.6 (0.58), with higher scores indicating more frequent participation in social activities. 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. 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 after controlling for potential confounders. 

The authors concluded that less frequent social engagement is associated with a more rapid rate of motor function decline in old age.