Loss of muscle strength, speed and dexterity is a common consequence of ageing, and a well-established risk factor for death, disability and dementia. Yet little is known about how and why motor decline occurs when it is not a symptom of disease.
Now, researchers at Rush University Medical Center have found that, among the elderly, less frequent participation in social activities is associated with a more rapid decline in motor function. The study is published in the 22 June issue of the Archives of Internal Medicine.
"It’s not just running around the track that is good for you," said Dr Aron Buchman, associate professor of neurological sciences at Rush University Medical Center. "Our findings suggest that engaging in social activities may also be protective against loss of motor abilities."
"If the causal relationship is confirmed by others, the implications are enormous for interventions that can help the elderly. Our data raise the possibility that we can slow motor decline and possibly delay its adverse health outcomes by supporting social engagement – a relatively low-cost solution to a very large public health problem."
The researchers recruited 906 older individuals from retirement facilities, subsidized housing complexes, church groups and social service agencies in northeastern Illinois who had no signs of dementia or history of Parkinson’s disease or stroke.
At the outset of the study, the participants filled out a survey indicating their level of participation in a variety of activities involving social interactions, such as doing volunteer work, visiting friends or relatives, or attending church or sporting events. Frequency of participation in these activities was measured using a five-point scale, with one indicating participation in a particular activity once a year or less; two, several times a year; three, several times a month; four, several times a week; and five, every day or almost every day. Demographic information, weight, height and disabilities were also recorded.
The researchers then annually assessed the participants’ basic motor function, including muscle strength in the arms and legs, and motor performance, including walking and balance. Participants were followed for an average of five years.
The study found that motor decline was more rapid in those who less frequently participated in social activities, with each one-point decrease in a participant’s social activity associated with an approximate 33-percent more rapid rate of decline.
A one-point decrease on the social activity scale was equivalent to being approximately five years older at the start of the study, according to Buchman.
"Statistically, that amount of change translates into a more than 40-percent increased risk of death and a more than 65-percent increased risk of developing disability," Buchman said.
Motor function was also associated, as expected, with other factors, such as joint pain, depression, disability and vascular disease, but even when these factors were considered in the analysis, the association between social activity and motor decline still held up.
"There is gathering evidence that physical activity is only one component of an active and healthy lifestyle. Studies have shown, for example, that increased cognitive and social activities in the elderly are associated with increased survival and a decreased risk of dementia," Buchman said. "Our study extends these findings, showing that social activity late in life is closely linked with healthy motor function."
Other researchers at Rush involved in this study were Patricia Boyle, PhD, Robert Wilson, PhD, Debra Fleischman, PhD, Sue Leurgans, PhD, and Dr David Bennett.
The study was funded by the National Institute on Aging, the Illinois Department of Public Health, and the Robert C. Borwell Endowment Fund.
(Source: Rush University Medical Center: Archives of Internal Medicine: June 2009)