Sarcopenia is far more than an inevitable consequence of growing old. It is a recognized clinical condition, formally defined by the European Working Group on Sarcopenia in Older People 2 as the combination of low muscle strength and low muscle quantity, and it is associated with falls, frailty, hospitalization, and death. Hepatic steatosis, the accumulation of fat inside liver cells, sits at the center of what clinicians now call metabolic dysfunction-associated steatotic liver disease, a renaming that reflects how tightly the condition is bound to obesity, type 2 diabetes, and dyslipidemia. Both conditions often coexist in older adults against a shared background of adiposity, diabetes, and functional decline, yet the precise relationship between them remains contested. Some researchers propose that insulin resistance and chronic low-grade inflammation link fat accumulation in the liver to muscle wasting; others argue that shared risk factors explain the co-occurrence without any direct causal pathway.

The research team, led by Hulusi Can Karpuzcu and Çağdaş Erdoğan, set out to test whether sarcopenia and fatty liver travel together in older adults, and whether the pairing extends to non-invasive markers of liver scarring. Between May 2025 and February 2026, they enrolled 344 consecutive adults aged 65 or older at a single center, a design intended to minimize selection bias within the clinic’s catchment population. Every participant underwent a standardized battery of assessments: bioelectrical impedance analysis to estimate body composition, handgrip dynamometry to measure strength, conventional abdominal ultrasonography to detect fatty liver, and a panel of blood tests including liver enzymes, platelet counts, and metabolic markers.

The technical approach to defining sarcopenia deserves attention because it shapes what the study can claim. Rather than relying on a single measure, the researchers derived skeletal muscle mass from fat-free mass using a fixed conversion formula — skeletal muscle mass equals 0.566 times fat-free mass — and then normalized it to height squared to produce a skeletal muscle mass index. Study-defined sarcopenia required both sex-specific low handgrip strength and a low skeletal muscle mass index, mirroring the two-part logic of international consensus definitions. This operational choice matters: different ways of measuring muscle quantity, whether by impedance, dual-energy X-ray absorptiometry, or imaging, can shift who crosses the threshold and therefore how prevalent the condition appears to be.

The headline result was striking. Sarcopenia was identified in 82 of 344 participants, or 23.8 percent — roughly one in four older adults in the sample. Sonographic steatosis was present in 78 percent of participants with study-defined sarcopenia and 54.2 percent of those without it, a difference that was highly statistically significant before any adjustment. In plain terms, older adults whose muscles were weak and depleted were substantially more likely to carry fat in their livers, a pattern consistent with the hypothesis that the two conditions share metabolic roots.

But the picture grew more complicated once the researchers adjusted for confounders. In the main multivariable model — controlling for age, sex, body-fat percentage, diabetes, and hyperlipidemia — the association remained positive but lost statistical precision, with an odds ratio of 1.88 and a 95 percent confidence interval of 0.99 to 3.54, yielding a p-value of 0.052. An odds ratio of 1.88 suggests that sarcopenia nearly doubles the odds of fatty liver, but the confidence interval just barely includes the null value of 1.0, meaning the data cannot rule out no association at conventional significance thresholds. When the team swapped body-fat percentage for body mass index in a sensitivity analysis, the estimate grew larger and became statistically significant: an odds ratio of 2.97, with a confidence interval of 1.56 to 5.66 and a p-value of 0.001. The fact that the result varied with the adiposity measure used is not a technical footnote — it reveals how sensitive the association is to how researchers operationalize body composition, and how residual confounding by adiposity could inflate or deflate the apparent link.

The researchers then turned to non-invasive fibrosis risk indices, asking whether sarcopenia was associated not just with fat in the liver but with the early stages of scarring. They used two widely validated tools: the aspartate aminotransferase-to-platelet ratio index, or APRI, which combines a liver enzyme with a platelet count, and the Fibrosis-4 index, or FIB-4, which incorporates age, two liver enzymes, and platelets. In ordinary least-squares models with heteroskedasticity-consistent type 3 standard errors — a statistical technique that produces reliable standard errors even when the variability of the outcome differs across subgroups — sarcopenia was associated with higher APRI and FIB-4 values, including in an age-adjusted FIB-4 model. However, these associations were substantially attenuated after the researchers adjusted for the platelet component of the indices, a finding that carries important interpretive weight.

The attenuation after platelet-component adjustment is the study’s most sobering technical lesson. Both APRI and FIB-4 rely partly on platelet counts, which decline in advanced liver fibrosis as scarring increases pressure in the portal vein and the spleen sequesters platelets. But platelets also fall for many other reasons in older adults, including medications, inflammation, and hematologic conditions unrelated to the liver. If sarcopenia is associated with lower platelets through any non-fibrotic pathway, the indices will appear elevated without any true scarring. The authors are explicit on this point: the associations with higher APRI and FIB-4 values do not demonstrate fibrosis. This is a crucial distinction for readers and clinicians alike — a high FIB-4 score in an older adult with sarcopenia may reflect low platelets rather than a scarred liver, and treating it as proof of fibrosis could lead to unnecessary anxiety or invasive testing.

The authors are equally candid about the study’s limitations, and their transparency is a model of responsible research communication. The cross-sectional design captures a single moment in time and cannot establish whether sarcopenia causes fatty liver, whether fatty liver contributes to muscle wasting, or whether both arise from a third factor such as insulin resistance. Measurement uncertainty in bioelectrical impedance, which estimates muscle mass from electrical conductivity rather than direct imaging, introduces error that could bias the classification of sarcopenia. Selection bias — the possibility that people who seek care at this hospital differ from the general older population — and residual confounding by unmeasured factors such as physical activity, diet, and medications further constrain interpretation. The authors state plainly that the findings preclude causal, prognostic, or clinical risk-stratification conclusions.

Despite these constraints, the study offers a valuable contribution to a rapidly evolving field. The renaming of fatty liver disease to metabolic dysfunction-associated steatotic liver disease reflects a growing recognition that the condition is a systemic metabolic disorder, not simply a liver problem. If sarcopenia and hepatic steatosis share metabolic roots — insulin resistance, chronic inflammation, altered fat distribution — then screening older adults for one condition may warrant attention to the other. The finding that nearly one in four older adults in this sample had sarcopenia, and that fatty liver was present in more than three-quarters of them, underscores the scale of the potential overlap. Future longitudinal studies using direct imaging of muscle mass, repeated measures of liver fat, and careful disentangling of platelet effects from true fibrosis will be needed to determine whether the link is causal and whether it carries clinical consequences. For now, the study stands as a careful, technically rigorous snapshot that strengthens the case for viewing aging muscle and aging liver as partners in a shared metabolic decline — while reminding us how much uncertainty remains beneath the surface of that partnership.

Subject of Research: Sarcopenia and sonographic hepatic steatosis in older adults: associations with non-invasive fibrosis risk indices

Article Title: Sarcopenia and sonographic hepatic steatosis in older adults: associations with non-invasive fibrosis risk indices

Article References: Karpuzcu, H. C., & Erdoğan, Ç. (2026). Sarcopenia and sonographic hepatic steatosis in older adults: associations with non-invasive fibrosis risk indices. BMC Geriatrics. https://doi.org/10.1186/s12877-026-08512-5

Image Credits: AI Generated

DOI: 10.1186/s12877-026-08512-5

Keywords: sarcopenia, hepatic steatosis, fatty liver, aging, liver fibrosis, metabolic syndrome, BMC Geriatrics, sonographic, hepatic, steatosis, older, adults