SAN DIEGO — Older adults with diabetes are more likely to have poor muscle quality and accelerated loss of strength over a 3-year period, compared with their peers who don't have the disease, Seok Won Park, M.D., reported at the annual scientific sessions of the American Diabetes Association.
“These characteristics may contribute to the development of physical disability in older adults with diabetes,” said Dr. Park, an epidemiologist at the University of Pittsburgh.
Although it is known that older adults with diabetes face a two- to threefold higher risk of physical disability, this increased risk has not been studied with regard to changes in muscle characteristics, such as strength.
Dr. Park and his associates used an isokinetic dynamometer to evaluate knee extensor strength and used dual-energy x-ray absorptiometry (DXA) to measure muscle mass in a cohort of 1,863 men and women with a mean age of 74 who were enrolled in the Health, Aging, and Body Composition Study sponsored by the National Institute on Aging. Study participants returned for follow-up evaluations 3 years later.
The researchers defined muscle quality as muscle strength per unit of regional muscle mass in kilograms.
Baseline measurements revealed that older adults with diabetes had greater leg muscle mass than controls, but knee extensor strength was lower in diabetic men, compared with men in the control group.
Among women, absolute strength at baseline did not differ by diabetes status, but muscle quality was significantly lower in women with diabetes, compared with controls. This was also the case for men with diabetes.
At 3 years, men and women with diabetes showed a more rapid decline in muscle mass, compared with controls. This greater loss of leg muscle mass among older men and women with diabetes accounted for some of the loss of strength over the 3-year period, but they also had a larger decline in muscle quality, compared with controls, Dr. Park noted.
The results remained similar after the researchers adjusted for sex, age, race, combined chronic disease, smoking, alcohol consumption, and level of physical activity.