A new study from Wake Forest Baptist Medical Center shows that an increase in fat throughout the thigh is predictive of mobility loss in otherwise healthy older adults.
Lead author Kristen Beavers, Ph.D., and colleagues at Wake Forest Baptist said the findings suggest that prevention of age-related declines in walking speed isn't just about preserving muscle mass, it's also about preventing fat gain.
Walking speed declines with age, said Beavers, and in older adults slower walking speed is a predictor of disability, nursing home admission and even death. As such, she believes that walking speed represents an important, and potentially modifiable, predictor of independent living for older adults. Unfortunately, said Beavers, not much is known about what precedes this decline, although change in body composition seemed like a reasonable place to start the research. "As people age, they are more likely to gain fat in and around their muscles, and we speculated that gaining fat in the leg muscle itself would be related to slowed walking speed."
The researchers used data from the National Institute on Aging's Health, Aging, and Body Composition (Health ABC) study, a prospective cohort of several thousand initially well-functioning white and black adults aged 70-79. They looked at how changes in fat and lean mass affected walking speed, and were specifically interested in whether changes in thigh intermuscular fat or thigh muscle area were more predictive of slowed walking speed.
A study sample of 2,306 men and women was reviewed, with a mean age of 74.6 years. Walking speed was assessed by measuring the usual time it took participants to complete a 20-minute walk, and they were tested annually over a four-year period. Body composition measures were assessed via computed tomography (CT).