Association between leg-to-trunk lean mass ratio measured by dual-energy X-ray absorptiometry and later falls in older Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) cohort study.

BACKGROUND

Sarcopenia, defined as "decreased lean mass (LM) plus low muscle strength and/or low physical performance," is associated with a high risk of falls and fractures. Although an association between muscle strength and falls has been reported, the association between LM and falls remains unclear, with previous studies reporting conflicting findings. We investigated the association of LM measured precisely by dual-energy X-ray absorptiometry with later falls in community-dwelling Japanese men aged 65 years or more at the time of the baseline survey.

METHODS

The present analyses included 507 older men who provided complete information on LM and falls in the Fujiwara-kyo Osteoporosis Risk in Men cohort study. Whole-body LM and regional LM were measured from 2017 to 2019. LM in each body region, including the legs and trunk, was recorded. The leg-to-trunk LM ratio, calculated as leg LM divided by trunk LM, was also analyzed. Information on falls that occurred in the 12 months prior to the 2022-2023 follow-up survey was obtained.

RESULTS

Mean trunk LM was significantly larger, and mean leg-to-trunk LM ratio significantly smaller, in fallers than in non-fallers (P < 0.05). Multiple logistic regression analysis revealed that leg-to-trunk LM ratio was significantly inversely associated with falls after adjusting for potential confounders (P < 0.05), whereas no significant associations were observed between whole-body and regional LM and falls.

CONCLUSION

Leg-to-trunk LM ratio was associated with later falls in community-dwelling older Japanese men. Older men with a larger distribution of leg LM relative to trunk LM tended to have a lower risk of later falls.