Evaluation of the association between vitamin d status, physical performance and lean body MASS

This study aimed to determine the association between vitamin D status, physical performance and lean body mass. 100 female patients with 35-50 age range, applying to BEU Faculty of Medicine, Physical Medicine and Rehabilitation Clinic between November 1, 2014 and April 1, 2016 were included in our study. Demographic informations (age, marital status, education status, occupation), heights and weights of the patients were investigated and their levels of body mass index (BMI) were calculated. 25-hydroxyvitamin D (25(OH)D) levels were tested in blood serum of patients. Patients were divided into 2 groups according to their 25-hydroxyvitamin D levels; patients with low vitamin D levels (Group 1) and patients with normal vitamin D levels (Group 2). Lean body mass was assessed by Dual-energy X-ray absorptiometry (DXA) and physical performance was assessed by 6-minute walk test (6MWT). Mean levels of 25(OH)D were found 14,026 ± 7,10 ng/ml in Group 1 and 43,40 ± 10,03 ng/ml in Group 2. Difference in mean levels of 25(OH)D between groups was significant (p=0,000). Mean ages were found 41,96 ± 4,37 year in group 1 and 40,56 ± 3,62 year in group 2. In terms of age, no significant difference was determined between groups (p=0,128). When 2 groups compared in terms of BMI, fat mass (FM), fat rate and bone mineral content (BMC), no statistically significant difference was found (one by one p= 0,778; p=0,544; p=0,629; p=0,728). Mean levels of lean body mass (LBM) were found 36,09 ± 4,67 kg in Group 1 and 35,76 ± 4,28 kg in Group 2. In terms of mean levels of lean body mass (LBM) no significant difference were found between groups (p=0,679). Mean levels of 6-MWT were found 468,94 ± 42,76 meter in Group 1 and 469,22 ± 45,376 meter in Group 2. As a result of 6-MWT, no statistically significant difference between 2 groups was determined (p=0,992). In both group 1 and group 2, statistically significant association was determined between LBM and BMI, BMC, FM. A significant association between LBM, 25(OH)D and 6-MWT levels of all subjects included in this study, was not observed. According to serum 25(OH)D level, group 1 were divited into three sub-groups as follow. Group 1a:25(OH)D < 10 ng/dl, Group 1b: 10.1≤25(OH)D≤ 20 ng/dl and Group 1c: 20.1≤25(OH)D≤29.9 ng/dl. When subgroups of group 1 (group 1a, group 1b, group 1c) and group 2 compared, in terms of mean levels of LBM and 6-MWT, no significant difference was observed (one by one, p = 0,975; p = 0,644). As a result in our study no significant association was observed between serum 25(OH)D levels , physical performance and lean body mass. More studies with same exlusion criteria are needed particularly those asses serum 25(OH)D with genetic factors influence functions of vitamin D and muscle mass with muscle quality.