An increase in fat throughout the thigh is predictive of mobility loss in otherwise healthy older adults, according to a study.
Kristen Beavers, PhD, and colleagues at Wake Forest Baptist Medical Center said the findings suggest prevention of age-related declines in walking speed is about preventing fat gain in addition to preserving muscle mass.
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 walking speed represents an important and potentially modifiable predictor of independent living for older adults.
Unfortunately, Beavers said in a news release, not much is known about what precedes this decline, although change in body composition seemed like a reasonable place to start investigating. "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 ages 70 to 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 an average age of 74.6 years. Walking speed was assessed by measuring the usual time participants took to complete a 20-minute walk, with participants tested annually over a four-year period. Body composition measures were assessed via computed tomography.
Results, scheduled for publication in the American Journal of Clinical Nutrition, found both increasing thigh intermuscular fat and decreasing thigh muscle area to be significant and independent predictors of walking speed decline. Importantly, said Beavers, older adults who gained the most thigh fat and lost the most thigh muscle were at greatest risk of experiencing a clinically meaningful decline in walking speed.
Beavers said the study is the first of its kind to address the independent association between changes in sophisticated measures of body composition and walking speed.
"As the burden of disability becomes increasingly common and expensive, identification of modifiable contributors to functional decline in older adults is emerging as a significant priority of public health research," Beavers said. "Future studies building on these findings should test whether targeted reductions in thigh intermuscular fat, augmentation of thigh muscle area or both yield improvements in walking speed and prolonged independence for older adults."
The study abstract is available at http://ajcn.nutrition.org/content/early/2013/01/30/ajcn.112.047860.abstract.
Kristen Beavers, PhD, and colleagues at Wake Forest Baptist Medical Center said the findings suggest prevention of age-related declines in walking speed is about preventing fat gain in addition to preserving muscle mass.
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 walking speed represents an important and potentially modifiable predictor of independent living for older adults.
Unfortunately, Beavers said in a news release, not much is known about what precedes this decline, although change in body composition seemed like a reasonable place to start investigating. "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 ages 70 to 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 an average age of 74.6 years. Walking speed was assessed by measuring the usual time participants took to complete a 20-minute walk, with participants tested annually over a four-year period. Body composition measures were assessed via computed tomography.
Results, scheduled for publication in the American Journal of Clinical Nutrition, found both increasing thigh intermuscular fat and decreasing thigh muscle area to be significant and independent predictors of walking speed decline. Importantly, said Beavers, older adults who gained the most thigh fat and lost the most thigh muscle were at greatest risk of experiencing a clinically meaningful decline in walking speed.
Beavers said the study is the first of its kind to address the independent association between changes in sophisticated measures of body composition and walking speed.
"As the burden of disability becomes increasingly common and expensive, identification of modifiable contributors to functional decline in older adults is emerging as a significant priority of public health research," Beavers said. "Future studies building on these findings should test whether targeted reductions in thigh intermuscular fat, augmentation of thigh muscle area or both yield improvements in walking speed and prolonged independence for older adults."
The study abstract is available at http://ajcn.nutrition.org/content/early/2013/01/30/ajcn.112.047860.abstract.
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