Both low and high levels of vitamin D are associated with increased risk of frailty in older women, a study finds.
Researchers measured vitamin D levels and assessed frailty in thousands of women aged 69 and older. The risk of frailty was lowest among women with vitamin D levels between 20 and 299 nanograms per milliliter (ng/ml) and highest among women with vitamin D levels less than 20 ng/ml and more than 30 ng/ml.
The study has been accepted for publication in The Journal of Clinical Endocrinology & Metabolism.
Vitamin D deficiency and frailty are common with aging. Many experts recommend monitoring vitamin D levels in older adults and prescribing vitamin D supplementation if levels are less than 30 ng/ml. But these study findings raise questions about that practice.
"Vitamin D supplementation has grown in popularity, yet the association between vitamin D status and risk of adverse health outcomes in older adults is uncertain," explained lead author Kristine Ensrud, MD, a professor of medicine and epidemiology at Minneapolis VA Medical Center and the University of Minnesota, in an Endocrine Society news release.
The industry-sponsored Vitamin D Council, in fact, recommends a "minimal acceptable" blood level of 50 ng/ml. But, Dr. Ensrud noted, "Our study did not find that higher vitamin D status (more than 30 ng/ml) was associated with lower subsequent risks of frailty or death. In fact, higher levels of vitamin D were associated with increased likelihood of frailty."
Further studies are needed to fully evaluate the effects of vitamin D supplementation on the progression of frailty, Dr. Ensrud concluded.
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