To determine the cross-sectional and longitudinal associations between 25-hydroxyvitamin D (25(OH)D) levels and frailty status in older men. Prospective cohort study. Six U.S. community-based centers. One thousand six hundred six men aged 65 and older. 25(OH)D (liquid chromatography tandem mass spectroscopy) and frailty status (criteria similar to those used in the Cardiovascular Health Study) measured at baseline; frailty status assessment repeated an average of 4.6 years later. Frailty status was classified as robust, intermediate, or frail at baseline and robust, intermediate, frail, or dead at follow-up. After adjusting for multiple potential confounders, men with 25(OH)D levels less than 20.0 ng/mL had 1.5 times higher odds (multivariate odds ratio (MOR)=1.47, 95% confidence interval (CI)=1.07-2.02) of greater frailty status at baseline than men with 25(OH)D levels of 30.0 ng/mL or greater (referent group), whereas frailty status was similar in men with 25(OH)D levels from 20.0 to 29.9 ng/mL and those with levels of 30.0 ng/mL or greater (MOR=1.02, 95% CI=0.78-1.32). However, in 1,267 men not classified as frail at baseline, there was no association between lower baseline 25(OH)D level and odds of greater frailty status at the 4.6-year follow-up. Findings were the same when 25(OH)D was expressed in quartiles or as a continuous variable. Lower levels of 25(OH)D (<20.0 ng/mL) in community-dwelling older men were independently associated with greater evidence of frailty at baseline but did not predict greater risk of greater frailty status at 4.6 years. © 2010, Copyright the Authors. Journal compilation © 2010, The American Geriatrics Society.
