Is the 25-hydroxy-vitamin D serum concentration a good marker of frailty?

Introduction: The phenotype proposed by Fried and colleagues is a widely used operational definition of frailty defining such state of extreme vulnerability of older persons. Low serum 25-hydroxy-vitamin D (25(OH)D) has been suggested as biomarker of frailty in literature. Study design: Cross-sectional. Objectives: To explore the association of 25(OH)D concentrations with the frailty phenotype and its criteria. Methods: 321 subjects referred by their general practitioner to a geriatric frailty clinic were assessed between January 1, 2013 and September 23, 2013. Adjusted logistic regression models were performed between serum concentrations of 25(OH)D and the frailty phenotype (global score as well as its specific criteria). Receivers operating curves were established in order to explore the existence of a possible threshold of vitamin D levels highly predictive of frailty. Results: Two hundred forty-one (75%) participants had 25(OH)D levels lower than 22 ng/ml. No significant association was reported between 25(OH)D levels and frailty. Among the five criteria of frailty, 25(OH)D was only associated with sedentariness (odds ratio 0.97 [95% confidence interval 0.95-0.99]). Conclusion: In our sample, no association was found between 25(OH)D levels and phenotype of frailty or the different frailty criterion except for sedentariness.