Outline of collaborative research
This collaborative research with the University of Jyväskylä in Finland has been conducted in the fields of gerontology and exercise physiology, aiming to elucidate the effects of vitamin D on skeletal muscle health during aging and the menopausal transition.
This study integrated the physiological and molecular biological knowledge of skeletal muscle metabolism at Ritsumeikan University with two large-scale longitudinal cohort studies maintained by the University of Jyväskylä, and analyzed data from approximately 1,100 middle-aged and elderly Finnish women.
The study used multivariate statistical models to rigorously examine the association between 25-hydroxyvitamin D (25(OH)D) levels and muscle mass, muscle strength, and physical function.
As a result, despite the majority of participants maintaining “sufficient” vitamin D levels (≥50 nmol/L) due to the effects of Finland's national vitamin D fortification policy, no statistically significant association was observed between 25(OH)D levels and muscle mass or muscle function. These findings suggest that in environments where vitamin D is already sufficiently supplemented, its standalone effect on improving muscle function is limited, and emphasize the importance of a multifactorial approach, including exercise, nutrition, and weight management, for preventing sarcopenia.
The results were published as an original article in the European Journal of Clinical Nutrition in 2025.
Papers, etc.
Peer-reviewed papers
- Fujita S, Lankila H, Koivunen K, Hakamäki M, Sipilä S, Portegijs E, Rantanen T, Laakkonen EK. Vitamin D sufficiency and its relationship with muscle health across the menopausal transition and aging: Finnish cohorts of middle-aged women and older women and men. Eur J Clin Nutr. 2025 Apr 2. doi: 10.1038/s41430-025-01610-4. Epub ahead of print. PMID: 40175705.
- Kuwabara A, Matsumoto M, Hatamoto Y, Fujita S. Vitamin D and muscle health: insights from recent studies. Curr Opin Clin Nutr Metab Care. 2024 Nov 1;27(6):499-506. doi: 10.1097/MCO.0000000000001071
Future prospects/aspiration
Going forward, we aim to advance international collaborative research on vitamin D status also with countries that have different dietary and exercise habits, in order to identify optimal lifestyle practices for preventing age-related declines in muscle mass and function in a wider context.
