Prospective association of vitamin D with frailty status and all-cause mortality in older adults: Results from the KORA-Age Study

Abstract Objective To assess the prospective association of serum 25-hydroxyvitamin D [25(OH)D] levels with frailty status and all-cause mortality in a cohort of community-dwelling participants of the population-based KORA [Cooperative Health Research in the Region of Augsburg]-Age Study. Methods 727 non-frail participants, aged ≥ 65 years, with 25(OH)D measurement at baseline in 2009, were followed for 2.9 ± 0.1 years. Participants were classified as pre-frail or frail if they met 1–2 or ≥ 3, respectively, of the following five criteria: weight loss, exhaustion, physical inactivity, low walking speed, weakness. The association between 25(OH)D and mortality was assessed in 954 participants. Multivariable adjusted logistic regression models were calculated for each outcome. Results The incidence of pre-frailty and frailty was 21.2% and 3.9% respectively. After multivariable adjustment, participants with very low 25(OH)D levels (< 15 ng/ml vs. ≥ 30 ng/ml) had a significantly higher odds for pre-frailty (OR = 2.43 [95% CI: 1.17–5.03]) and pre-frailty/frailty combined (OR = 2.53 [95% CI: 1.23–5.22]), but not for frailty alone (OR = 2.63 [95% CI: 0.39–17.67]). The association between 25(OH)D and mortality (OR = 3.39 [95% CI: 1.08–10.65]) was partly mediated by frailty status. Conclusion Very low 25(OH)D levels were independently associated with incident pre-frailty, pre-frailty/frailty combined and all-cause mortality.