The effect of muscle quality index on risk of adverse health outcomes: a prospective cohort study of 355,209 adults.
Level 3 - non-randomized controlled study
Prospective cohort study
PubMed 40930464 · doi:10.1016/j.ajcnut.2025.09.006
What was done
In a prospective cohort of 355,209 adults from the UK Biobank, researchers evaluated the muscle quality index (MQI), defined as the ratio of dominant hand grip strength to corresponding arm fat-free mass and categorized into sex-specific quintiles (Q1 to Q5). Cox proportional hazards models were used to examine associations between MQI and incidence of nine adverse health outcomes: osteoarthritis, cardiovascular disease (CVD), type 2 diabetes mellitus (T2DM), respiratory disease, chronic kidney disease (CKD), liver disease, dementia, depression, and all-cause mortality. Mediation analysis was performed using a metabolomic risk score (MRS) derived from 249 plasma metabolites via LASSO regression.
What was found
Compared with participants in the lowest quintile (Q1), those in Q2-Q5 had significantly lower risk for all nine outcomes (all P for trend < 0.001). Comparing Q5 to Q1, multivariable-adjusted hazard ratios were: - Osteoarthritis: 0.57 (95% CI: 0.55, 0.58) - CVD: 0.70 (95% CI: 0.68, 0.73) - T2DM: 0.36 (95% CI: 0.34, 0.39) - Respiratory disease: 0.72 (95% CI: 0.68, 0.76) - CKD: 0.58 (95% CI: 0.54, 0.61) - Liver disease: 0.53 (95% CI: 0.49, 0.56) - Dementia: 0.69 (95% CI: 0.64, 0.76) - Depression: 0.53 (95% CI: 0.50, 0.57) - All-cause mortality: 0.69 (95% CI: 0.66, 0.72) All associations were P < 0.001. The MRS partially mediated these associations, accounting for 9.98% to 42.86% of the effects.
Why it matters
This study shows that muscle functional capacity relative to mass is broadly protective against major chronic diseases and premature death, identifying circulating metabolic pathways as measurable intermediate mechanisms.
Limits
The observational design cannot establish causality or eliminate residual confounding. Follow-up duration, specific adjustment covariates, and repeat measurements of muscle quality over time are not reported in the abstract. UK Biobank participants exhibit a healthy volunteer selection bias.
Cited by
- partial Having high-quality skeletal muscle mass makes the occurrence of type 2 diabetes extraordinarily rare.