Vitamin D Levels in Pre-frail Older Adults and Its Correlation with Hand Grip Strength

Background: Vitamin D deficiency is frequent in older adults and associated with poor musculoskeletal function. The prevalence of pre-frailty is also high in older persons, who may proceed to a frail state. This study aimed to determine the vitamin D levels in pre-frail older adults and its correlation with hand grip strength. Methods: A cross-sectional study was conducted on older adults (age > 60 years) with a pre-frail condition who were visiting the outpatient geriatric clinic at Cipto Mangunkusumo Hospital in Jakarta, Indonesia. Serum levels of vitamin D, measured as 25(OH)D, were determined by enzyme-linked immunosorbent assay (ELISA), and hand grip strength was measured using a Jamar hydraulic dynamometer. Correlations between vitamin D levels and hand grip strength were evaluated by Spearman’s rank correlation coefficient. Multiple linear regression analysis was carried out to assess contribution of variables that influence hand grip strength. Results: Of 95 pre-frail older adults (mean age 70.08 ± 5.35 years), 67.4% were female, and the median vitamin D level was 17.91 (interquartile range/IQR 13.68–26.36) ng/mL. Overall, 11.6% of the participants had normal vitamin D levels, whereas 34.7% and 53.7% had insufficient and deficient levels, respectively. Females were more likely to have inadequacy of vitamin D than males. Those with vitamin D deficiency tended to have a higher body mass index (BMI) and lower vitamin D intake than normal levels. A significant correlation between serum vitamin D levels and hand grip strength was observed (r = 0,283; P = 0,006). After adjusting for age, comorbidities, nutritional status, functional status, BMI, protein intake, and sun exposure score, regression analysis between hand grip strength and vitamin D levels gave standard coefficient beta = 0,255 (P = 0,013). Conclusion: In this study, pre-frail older adults had a high proportion of deficient and insufficient vitamin D levels, and a significant correlation was found between serum vitamin D levels and hand grip strength.