Associations between serum 25-hydroxyvitamin D3 level and skeletal muscle mass and lower limb muscle strength in Japanese middle-aged subjects

Akiko Kuwabara; Naoko Tsugawa; Hiroshi Kondo; Misora Ao; Hitomi Fujiwara; Natsuki Hosokawa; Shiho Matsumoto; Kiyoshi Tanaka; Tetsuo Nakano

doi:10.1016/j.afos.2017.02.002

Associations between serum 25-hydroxyvitamin D₃ level and skeletal muscle mass and lower limb muscle strength in Japanese middle-aged subjects

Osteoporos Sarcopenia. 2017 Mar;3(1):53-58. doi: 10.1016/j.afos.2017.02.002. Epub 2017 Mar 7.

Authors

Akiko Kuwabara¹, Naoko Tsugawa¹, Hiroshi Kondo², Misora Ao³, Hitomi Fujiwara¹, Natsuki Hosokawa¹, Shiho Matsumoto¹, Kiyoshi Tanaka³, Tetsuo Nakano²

Affiliations

¹ Department of Health and Nutrition, Osaka Shoin Women's University, 4-2-26 Hishiyanishi, Higashiosaka, Osaka 577-8550, Japan.
² Department of Orthopaedic Surgery, Tamana Central Hospital, 1950 Naka, Tamana, Kumamoto, 865-0064, Japan.
³ Department of Food and Nutrition, Kyoto Women's University, 35 Imakumano-kitahiyoshicho, Higashiyama, Kyoto 605-8501, Japan.

Abstract

Objectives: One of the important risk factors of falling is decreased muscle mass and muscle strength. Recently, there has been an increasing concern on the role of vitamin D in muscle strength and physical activity. Aim of our study is to examine the relationships between vitamin D status and muscle mass and muscle strength in middle-aged healthy adults.

Methods: Subjects were 40 healthy volunteers aged 42.0 ± 10.6 years old. Evaluation was made for serum vitamin D₃ metabolites including 25-hydroxyvitamin D₃ [25(OH)D₃] and 24,25-dihydroxyvitamin D₃ [24,25(OH)₂D₃] concentrations, lower limb muscle strength, and dietary intake by food frequency questionnaire. Body composition was measured by dual-energy X-ray absorptiometry (DXA), and appendicular skeletal mass index (ASMI) was calculated as skeletal muscle mass/squared height.

Results: 70% of the subjects had vitamin D insufficiency/deficiency (serum total 25(OH)D < 20 ng/mL), and female subjects had significantly lower serum total 25(OH)D level compared with males. Vitamin D insufficiency/deficiency group had significantly higher body fat, lower SMI and muscle strength, probably reflecting higher percentage of female subjects. Serum vitamin D₃ metabolites levels were significantly correlated with whole and site-specific ASMI, and lower limb muscle strength, except for the correlation between serum 24,25(OH)₂D₃ concentration and lower limb muscle strength. In addition, serum 25(OH)D₃ level was a positive significant predictor for both ASMI and lower limb muscle strength, while serum 24,25(OH)₂D₃ level was not their significant predictor.

Conclusions: Serum 25(OH)D₃ level was significantly correlated with both skeletal muscle mass and lower limb muscle strength.

Keywords: 24,25-dihydroxyvitamin D3; 25-hydoxyvitamin D3; Japanese subjects; Lower limb muscle strength; Skeletal muscle mass.