Walking speed ‘predicts longevity’

Stephanie Studenski of the University of Pittsburgh,and colleagues conducted a study to assess the association of gait speed with survival in older adults and to determine the degree to which gait speed explains variability in survival after accounting for age and sex.

The study included a pooled analysis of 9 participating studies (collected between 1986 and 2000),using individual data from 34,485 community-dwelling adults age 65 years or older with walking speed data available at the beginning of the study,followed up for 6 to 21 years.

During the course of the study,there were 17,528 deaths. The overall 5-year survival rate was 84.8 percent; the 10-year survival rate was 59.7 percent.

The researchers found that gait speed was associated with differences in the probability of survival at all ages in both sexes,but was especially informative after age 75 years.

At this age,predicted 10-year survival across the range of gait speeds ranged from 19 percent to 87 percent in men and from 35 percent to 91 percent in women.

“In this older adult population the relationship of gait speed with remaining years of life was consistent across age groups,but the absolute number of expected remaining years of life was larger at younger ages,” wrote the authors.

The researchers also found that predicted survival based on age,sex,and gait speed was as accurate as predictions based on age,sex,use of mobility aids,and self-reported function or as age,sex,chronic conditions,smoking history,blood pressure,body mass index,and hospitalization.

The authors suggested there are several reasons why gait speed may predict survival.

“Walking requires energy,movement control,and support and places demands on multiple organ systems,including the heart,lungs,circulatory,nervous,and musculoskeletal systems. Slowing gait may reflect both damaged systems and a high energy cost of walking,” they wrote.

However,Matteo Cesari of the Universita Campus Bio-Medico,Rome,wrote that because no evidence definitively supports the hypothesis that gait speed improvements are associated with better health-related outcomes,gait speed should not be considered as a primary target for interventions at this time.

The findings were published in the January 5 issue of JAMA.