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

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. 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. 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). 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.