Buchebner D, et al. - Researchers conducted this prospective, population-based, cohort study in Malmö, Sweden to explore the connection between 25OHD and frailty in older women followed for 10 years. The sample consisted of community-dwelling women, aged 75 years (N = 1,044) with reassessments at ages 80 (n = 715) and 85 (n = 382) years. Using a 10-variable frailty index, frailty was quantified. Study participants were categorized as 25OHD insufficient (< 50 nmol/L) or sufficient (≥ 50 nmol/L). According to results, women with inadequate 25OHD at 75 and 80 years of age were frailer than women with adequate 25OHD. At age 80 years, 25OHD insufficiency was related to subsequent frailty 5 years later. Accelerated frailty progression was not linked to lower 25OHD levels, and 25OHD level > 75 nmol/L was not additionally beneficial with regard to frailty. At the age of 85 years, there was no correlation between 25OHD and frailty. Variables associated with 25OHD were related to muscle strength and function within the frailty index. This research promotes the importance of maintaining adequate levels of 25OHD for healthy aging.