Low skeletal muscle mass index and all-cause mortality risk in adults: A systematic review and meta-analysis of prospective cohort studies.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of prospective cohort studies
PubMed 37285331 · doi:10.1371/journal.pone.0286745
What was done
Authors searched PubMed, Web of Science, and the Cochrane Library up to April 1, 2023, for prospective cohort studies evaluating the association between low skeletal muscle mass index (SMI) and all-cause mortality in adults. Data were synthesized using random-effects meta-analysis, subgroup analyses stratified by body mass index (BMI), meta-regression, sensitivity analyses, and publication bias assessments across follow-up durations ranging from 3 to 14.4 years.
What was found
Across 16 prospective cohort studies including 81,358 participants and 11,696 deaths: - Pooled relative risk of all-cause mortality for the lowest versus normal muscle mass category was 1.57 (95% CI: 1.25 to 1.96, P < 0.001). - Meta-regression indicated BMI was a potential source of between-study heterogeneity (P = 0.086). - Subgroup analyses by BMI showed an increasing relative risk of mortality with higher BMI categories: - BMI 18.5 to 25: RR 1.34 (95% CI: 1.24 to 1.45, P < 0.001) - BMI 25 to 30: RR 1.91 (95% CI: 1.16 to 3.15, P = 0.011) - BMI > 30: RR 2.58 (95% CI: 1.20 to 5.54, P = 0.015)
Why it matters
This meta-analysis demonstrates that low muscle mass is an independent predictor of all-cause mortality across adult populations, with the relative risk being notably greater among individuals with overweight and obesity.
Limits
The underlying studies are prospective observational cohorts, precluding definitive causal conclusions. The abstract does not specify the measurement techniques (e.g., DXA, BIA, CT) or cutoff thresholds used to define low SMI, nor does it report cause-specific mortality or adjust for all potential lifestyle confounders.
Cited by
- supports Being under-muscled is associated with a 50% to 75% increase in all-cause mortality across studies.