By Bruce Sylvester
Journal of Gerontology
So your mom told you to take your vitamins? Tell her to do likewise. A new study published in the (2007;62:440446) reports that a low vitamin D status puts older persons at risk for poor physical functioning, potentially compromising their ability to perform daily tasks.
"The study was well powered, with a large sample of community-dwelling elderly men and women ages 65 to 102," Stephen Roth, PhD, assistant professor of kinesiology at the University of Maryland, College Park, told . "And similar relationships were observed in both men and women, making the findings more generalizable to the elderly community as a whole."
Current guidelines suggest that persons aged 50 to 69 years need at least 400 IU of vitamin D daily, and those older than 70 need 600 IU daily. "There is a growing awareness that the prevalence of low vitamin D levels is common among the elderly," the investigators write, adding that other research indicates that about 25% of persons older than 60 have low levels of vitamin D.
This study included a subanalysis of data from InCHIANTI, a study of factors contributing to decline in mobility among 976 patients aged ≥65 years. The study was originally conducted in 2 towns in the Chianti region of Italy.
Patients underwent a battery of tests to assess walking speed, ability to get up from a chair, and ability to maintain balance in progressively more difficult positions. They were also tested for handgrip strength, which indicates potential future disability.
Serum vitamin D levels showed that 28.8% of the women and 13.6% of the men were vitamin D deficient. In addition, 74.9% of the women and 51% of the men had serum vitamin D levels indicating insufficiency.
"Older men and women with low vitamin D levels had approximately 5% to 10% lower scores on the physical performance battery—which included walking speed, chair stands, and balance tests—and lower handgrip strength, compared with those with sufficient vitamin D levels," lead investigator Denise Houston, PhD, instructor in gerontology and geriatric medicine at Wake Forest University School of Medicine in Winston-Salem, NC, tells .
"The differences we found in physical performance among men and women with low and sufficient vitamin D levels approached the level considered to be clinically meaningful—differences that may result in those with lower vitamin D levels finding it more difficult to perform activities of daily living, such as getting out of a chair or walking short distances," she adds.
The findings were not affected by variables such as body mass index, physical activity level, season of the year, mental ability, health conditions, or anemia.
Dr Roth notes that this study contributes significantly to the body of evidence that includes several studies showing the potential impact of low vitamin D levels on physical performance and other comorbidities in the elderly.
"The evidence is now strong enough that clinicians should routinely prescribe vitamin D supplementation for their elderly patients. While clinical measurement of vitamin D would be preferable for each patient, measurement costs probably outweigh benefits, since the risk of vitamin D overdose is minimal," Dr Roth says.