Low, high vitamin D levels may raise risk of frailty in older women

Ensrud KE. J Clin Endocrinol Metab. 2010;95:5266-5273.

Issue: June 2011

Both low and high levels of circulating 25-hydroxyvitamin D increased the likelihood of frailty in older women, according to recent data.

“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,” Kristine Ensrud, MD, professor of medicine and epidemiology at the Minneapolis VA Medical Center and the University of Minnesota, said in a press release. “Our study did not find that higher vitamin D status was associated with lower subsequent risks of frailty or death. In fact, higher levels of vitamin D were associated with increased likelihood of frailty.”

The study included 6,307 women aged 69 years and older who were enrolled in the Study of Osteoporotic Fractures. The researchers examined women once at baseline and again after an average of 4.5 years for frailty status and 25-hydroxyvitamin D 25(OH)D levels.

At baseline, the researchers characterized 16.9% of the women as frail. When using women with 25(OH)D levels between 20 ng/mL and 29.9 ng/mL as the referent group, they also found the odds of frailty were higher among those with levels lower than 15 ng/mL (multivariable OR=1.47; 95% CI, 1.19-1.82) and those with levels between 15 ng/mL and 19.9 ng/mL (multivariable OR=1.24; 95% CI, 0.99-1.54). Women with levels of 30 ng/mL or greater also had an increased likelihood of frailty (multivariable OR=1.32; 95% CI, 1.06-1.63).

For the 4,551 women deemed robust or intermediate at baseline, those with 25(OH)D levels between 15 ng/mL and 19.9 ng/mL also had elevated odds for frailty or death at follow-up (multivariable OR=1.21; 95% CI, 0.99-1.49).

Women with levels lower than 15 ng/mL and those with levels of at least 30 ng/mL, however, did not appear to have increased likelihood for frailty or death. Nevertheless, odds of death alone were higher among participants with levels lower than 15 ng/mL (multivariable OR=1.4; 95% CI, 1.04-1.88). Those with levels between 15 ng/mL and 19.9 ng/mL demonstrated a similar, yet statistically insignificant, association.

“Evidence is lacking to support use of vitamin D supplementation for prevention of frailty and other outcomes including cancer or all-cause mortality,” Ensrud said. “Our results indicate that well-designed large randomized trials of sufficient duration are needed to accurately quantify health effects of vitamin D supplementation, including whether or not supplementation reduces the incidence or progression of frailty in older adults.”

Dr. Ensrud has no direct financial interest in any of the products mentioned in this article nor is she a paid consultant for any companies mentioned.

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