Fig. 4From: Low 25-hydroxyvitamin D levels and the risk of frailty syndrome: a systematic review and dose-response meta-analysisRisk ratios (RRs) and the corresponding 95% confidence intervals (CIs) for the dose-response relationship between serum 25-hydroxyvitamin D concentrations (nmol/L) and risk of frailty syndrome among the populations. a, cross-sectional studies; b, prospective cohort studies. The solid and long-dashed lines represent the estimated RRs and their 95% CIs, respectively. The short-dashed line represents the non-linear relationshipBack to article page