Association of intermuscular and intramuscular fat with insulin resistance, type 2 diabetes, and metabolic syndrome: A systematic review.
Level 3 - non-randomized controlled study
Systematic review of observational studies
PubMed 42485932 · doi:10.1016/j.clnu.2026.106727
What was done
This systematic review followed PRISMA 2020 guidelines to evaluate the association between muscle fat infiltration and metabolic outcomes in adults aged 18 and older. Databases (PubMed, Scopus, Web of Science, Cochrane Library) were searched from inception to March 2025 for studies reporting odds ratios (ORs) for muscle fat—measured via CT, MRI, or pQCT—associated with HOMA-IR, type 2 diabetes (T2D), and metabolic syndrome (MetS). Quality was assessed using the Newcastle-Ottawa Scale (NOS), and evidence was synthesized narratively due to high heterogeneity.
What was found
Seventeen studies were included (cohort sample sizes n = 2945–8081; 61.7% men; age range 34.3–74.6 years; mostly community-dwelling). Intermuscular fat showed significant associations with HOMA-IR (OR 2.67–2.72), T2D (OR 1.22–3.27 across multiple studies), and MetS (OR 1.2–2.3). Intramuscular fat was linked to higher HOMA-IR (OR 2.83) and MetS (OR 2.46), with mixed results for T2D. Muscle attenuation was associated with T2D (OR 1.26–1.36) and MetS (OR 1.35–1.77) with variations by sex. Study quality was moderate (NOS 5–6) for the majority of studies and high (NOS 8) for others.
Why it matters
This review confirms that ectopic fat infiltration within and between skeletal muscles is consistently linked to cardiometabolic dysfunction, highlighting myosteatosis as an important marker of metabolic risk.
Limits
High heterogeneity precluded quantitative meta-analysis, requiring narrative synthesis. Most included studies were only of moderate methodological quality (NOS 5–6). Observational designs prevent causal inference, and imaging modalities (CT, MRI, pQCT) and sex-specific definitions varied across studies.
Cited by
- supports Having high-quality skeletal muscle makes it significantly harder to develop metabolic disorders.