# Dual-energy X-ray absorptiometry-measured lean mass and clinical bone fracture in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) cohort study

## TL;DR

This study finds that lower lean mass measured by DXA in elderly Japanese men is linked to a higher risk of future bone fractures.

## Contribution

The study provides new evidence that DXA-measured lean mass is a predictor of clinical bone fractures in elderly men.

## Key findings

- Lower arm, leg lean mass, and leg-to-trunk lean mass ratio were significantly associated with reduced odds of clinical bone fractures.
- DXA-measured lean mass provides useful information for predicting and managing bone fractures in elderly men.
- Low skeletal muscle mass, estimated via appendicular lean mass, is linked to increased fracture risk.

## Abstract

Bone fractures pose a significant socioeconomic burden for both women and men in aging societies. It has been reported that lean mass (LM) measured by dual-energy X-ray absorptiometry (DXA) may be associated with fractures. However, evidence regarding the relationship between DXA-measured LM and fractures remains inconsistent.

We investigated the association between DXA-measured LM and clinical bone fractures in community-dwelling elderly Japanese men from the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) cohort study. The source population consisted of 948 elderly men who underwent LM measurement by DXA at the time of the 2017–2019 survey. Among these, 780 participants who provided complete information regarding clinical fracture experience in the follow-up survey conducted in 2022–2023 were included in the analysis (mean age at the time of the 2017–2019 survey, 80.2 years; standard deviation, 3.8).

From the 2017–2019 survey to the 2022–2023 follow-up survey, 52 participants had experienced one or more clinical bone fractures including osteoporotic and non-osteoporotic fractures. Odds ratios of clinical bone fracture for arm LM, leg LM, and leg-to-trunk LM ratio were significantly lower than 1.0 after adjusting for potential confounding factors including age, nutrition intake, and physical performance.

DXA-based appendicular LM predicts future clinical bone fractures in elderly Japanese men, suggesting that elderly men with low skeletal muscle mass, which can be accurately estimated from appendicular LM, may be prone to future clinical fractures. DXA-measured LM thus provides additional information useful for the management of bone fractures.

The online version contains supplementary material available at https://doi.org/10.1265/ehpm.25-00449.