Fat-to-muscle ratio, frailty and proteomic age acceleration in UK Biobank
In this cross-sectional UK Biobank analysis, higher total and regional fat-to-muscle ratios were associated with higher odds of pre-frailty and frailty in both sexes, most clearly for the arm ratio, and with multi-organ proteomic age acceleration. [1]
Automatic summary · not editorially reviewed
The key findings
This cross-sectional analysis included 445,317 UK Biobank participants, with 39,782 in the proteomic analyses. [1]
Per one-standard-deviation higher arm ratio, the frailty odds ratio was 1.86 in men and 2.95 in women. [1]
Higher fat-to-muscle ratios and frailty status were associated with multi-organ proteomic age acceleration. [1]
The source at a glance
- Study type / format
- Cross-sectional analysis (abstract)
- Population / context
- 445,317 UK Biobank participants, of whom 39,782 were in the proteomic analyses.
- Summary based on
- Study abstract
- Original publication
- September 17, 2026
Cross-sectional UK Biobank body-composition question
The study asked whether the fat-to-muscle ratio, which reflects the imbalance between fat accumulation and estimated muscle mass, is associated with frailty and with multi-organ proteomic age acceleration. This cross-sectional analysis included 445,317 UK Biobank participants, of whom 39,782 took part in the proteomic analyses. Whole-body, trunk, leg and arm ratios were derived from bioelectrical impedance. Frailty status was defined using an adapted Fried phenotype.
Supporting source [1]
Higher arm ratio linked to frailty odds in both sexes
Higher total and regional fat-to-muscle ratios were associated with greater odds of pre-frailty and frailty in both sexes; the arm ratio showed the most pronounced regional associations. Per one-standard-deviation higher arm ratio, the odds ratio for frailty was 1.86 (95% confidence interval 1.79–1.92) in men and 2.95 (2.75–3.18) in women. Adding arm ratio to body mass index-based models raised the area under the receiver operating characteristic curve by 0.0137 in men and 0.0068 in women. These are associations, not evidence of cause.
Supporting source [1]
Proteomic age acceleration and abstract-only scope
Higher fat-to-muscle ratios and frailty status were associated with multi-organ proteomic age acceleration, with the clearest concordance for arm ratio-related and frailty-related patterns. Organ-specific proteomic age-acceleration measures were derived using published ageing models. The authors conclude that regional fat-muscle imbalance, particularly in the arms, may provide complementary information on frailty-related body composition beyond body mass index. This explainer is based on the abstract only; the full text was not reviewed, and the cross-sectional design cannot establish temporal order or causation.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. This is a cross-sectional analysis, so associations cannot establish temporal order or causation. Proteomic results come from a subset of 39,782 participants.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Sun Z, Jia T, Li M, Guo X, Wu S, Ouyang Y, Gao Y, Su C, Yu S, Han P, Kou C, Bai W. · europepmc.org · September 17, 2026