Skeletal muscle function and vitamin D

Age-related changes in muscle strength and physical functions, and the association between vitamin D status and skeletal muscle functions were investigated in 36 men (21-90 years old) and 52 women (21-104 years old). Significant ageing-related decreases in several skeletal muscle functions and serum 25-hydroxyvitamin D [25(OH)D] levels were observed in both men and women. Cut-off values for the Timed up and go (TUG) test, walking speed, handgrip strength and Barthel Index (BI) detecting walking difficulties in the receiver operating characteristic (ROC) analysis were 11.1 sec, 0.60 m / sec, 17.0 kg, and 90.0 in males, and 28.6 sec, 0.43 m / sec, 13.9 kg, and 67.5 in females, respectively. By comparing personal present data of muscle strength with these cut-off values, people can easily understand their process to walking difficulty. Therefore, these results are important and useful to avoid or to delay a handicapped and dependent status by improving the vitamin D level, rehabilitation and nursing care

Skeletal muscle mass and vitamin D

A clearer understanding of skeletal muscle mass (SMM) in middle-aged and elderly individuals is important for maintaining functionality. In the present study, age-related changes in SMM, the threshold of SMM with walking difficulty, intestinal nutrient absorption rate, and various serum factors were examined in Japanese populations of different ages. We used 24-h creatinine excretion as a measure of total body SMM. Age-related decreases in SMM, intestinal nutrient absorption rates, and serum 25-hydroxyvitamin D [25(OH)D] concentrations were significantly higher in women than in men. The cut-off values for SMM (kg), its percentage of total body weight (BW), the SMM index [SMMI] (Kg / m2), and creatinine height index (CHI) (%) in elderly individuals with walking difficulty were approximately 8-10 kg, 17-20% of BW, 3.9-4.6 kg / m2, and 44%, respectively. Serum 25(OH)D concentrations were closely associated with SMM (kg, % of BW, kg / m2) and CHI (%) as well as the intestinal absorption rates of nitrogen (%) and phosphorus (%) in women, but not in men. The present results demonstrate that vitamin D is an important metabolic factor in skeletal muscle, and contributes to the optimal management of skeletal muscle and the prevention of sarcopenia

Skeletal muscle mass of old Japanese women suffering from walking difficulty in nursing home

By using 24 hour urinary creatinine levels, skeletal muscle mass (kg), its rate (%) of body weight and creatinine height index (%) were determined in old Japanese women suffering from walking difficulty in nursing home and compare with those of young university students. Those of old subjects showed approximately 30- 50%, 36-44% and44-46% of young subjects, respectively. It is suggested that these values are important and useful biomarkers for the planning and the achievement of rehabilitation program for the maintaining and restoring skeletal muscle mass and for the careful support by registered care workers to aged persons