Low lean mass and all-cause mortality risk in the middle-aged and older population: a dose-response meta-analysis of prospective cohort studies

Juan Li^1,2Xiaoling Liu³qing Yang³Wenying Huang⁴Zhibin Nie^1*Ya-Hai Wang^1*

• ¹Nanchang Normal College of Applied Technology, Nanchang, China
• ²College of Arts and Physical Education, Nanchang, China
• ³Wuhan Sixth Hospital, Wuhan, Hubei Province, China
• ⁴Jiangxi Normal University, Nanchang, Jiangxi Province, China

Objective: The accelerated aging process has raised substantial public health concerns regarding the health of the middle-aged and older population. The aim of our study was to investigate the association between low lean mass and the risk of all-cause mortality in older people, with the goal of promoting a long lifespan and reducing public health burdens.Methods: Three databases (PubMed, Web of Science, and Scopus) were searched for articles before May 22, 2025. The quality of the included articles was assessed using the Newcastle-Ottawa Scale (NOS). A meta-analysis was conducted using a random effects model. Subgroup analysis and meta-regression analysis were performed based on research characteristics. A dose-response analysis was performed to assess the specific association between lean mass and the risk of all-cause mortality. Sensitivity analysis was conducted using a leave-one-out meta-analysis. Publication bias analysis was conducted using Begg's and Egger's tests, as well as a funnel plot.Result: In total, 11 studies involving 130,079 participants were included in the metaanalysis of the association between low lean mass and the risk of all-cause mortality in the middle-aged and older population, all of which the included studies were of high quality. The average overall study quality score was 8 points. The random effects model analysis results showed that the pooled RR of all-cause mortality risk in the middleaged and older population was 1.30 (95% CI, 1.16 to 1.47, P < 0.001) across the lowest to normal lean mass category. There was an inverse nonlinear dose-response relationship between lean mass and the risk of all-cause mortality (P < 0.001).Low lean mass was significantly associated with 30% higher risk of allcause mortality in the middle-aged and older population. These findings highlighted low lean mass as an important risk factor for mortality in middle-aged and older population, warranting its integration into clinical assessments. Future research should establish causality through longitudinal studies and randomized trials, while refining diagnostic cutoffs for diverse populations.