RESUMEN
CONTEXT: Vitamin D is a steroid hormone that acts by binding to the vitamin D receptor (VDR) found in many tissues. According to the long-term mechanism, vitamin D causes the proliferation and differentiation of muscle cells by gene transcription. OBJECTIVE: We aimed to evaluate the relationship between muscle strength and serum vitamin D levels in elderly men. DESIGN: Cross-sectional study. SUBJECTS AND METHODS: Male patients over age 50 were included in the study. Study population was divided into 2 groups with handgrip strength according to body mass index, either as subjects with weak or with normal handgrip strength test (HGST). Vitamin D levels and other variables compared between weak and normal groups. RESULTS: Vitamin D level of weak and normal groups were 7.5 (3-19.9) µg/L, and 11.6 (11.6-34.9) µg/L, which means significant reduced vitamin D levels in weakness group (p=0.01). Vitamin D levels were significantly correlated with HGST levels (r:0.362, p=0.001). Vitamin D levels were found to be an independent predictor of weakness according to HGST in logistic regression analysis (OR: 0.453, 95% Cl:0.138-0.769, p=0.05). CONCLUSIONS: Low vitamin D level is an independent risk factor for muscle weakness in men aged more than 50 years. Therefore, vitamin D levels should be screened and early replacement should be initiated for the sake of improvement of muscle strength in elderly subjects that vulnerable for frailty.