Sleep-Disordered Breathing Linked to MASLD, but Evidence Certainty Is Low

Patients with sleep-disordered breathing (SDB), including obstructive sleep apnea (OSA), were 3.62 times as likely to have metabolic dysfunction-associated steatotic liver disease (MASLD) or hepatic steatosis compared with those without SDB or with less severe disease, according to a systematic review and meta-analysis published in Frontiers in Medicine.¹

Continuous positive airway pressure (CPAP) therapy was associated with lower liver enzyme levels, but controlled trials did not show consistent improvements in liver fat or fibrosis. The authors rated the certainty of evidence as low to very low for all outcomes.

Why Sleep Apnea Matters in Steatotic Liver Disease

MASLD, previously called nonalcoholic fatty liver disease, affects up to one-third of the worldwide adult population, epidemiologic data suggest.^1,2 OSA shares many of its risk factors, including obesity, insulin resistance, and type 2 diabetes, the authors noted. Intermittent hypoxia during sleep has been linked in experimental research to oxidative stress, mitochondrial dysfunction, and liver stellate cell activation, all of which are processes involved in fibrosis.

The study authors searched 6 databases through May 15, 2026, and included 22 studies.¹ These ranged from bariatric surgery and sleep clinic cohorts to randomized CPAP trials, with sample sizes from 9 to 410 participants.

MASLD and Fibrosis Prevalence in Patients With SDB

Across 8 studies, the pooled prevalence of MASLD or steatosis among patients with SDB was 75.1% (95% CI, 64.1%-83.6%). Pooled prevalence of liver fibrosis or fibrosis risk was 13.9% (95% CI, 6.0%-29.0%) across 5 studies. Heterogeneity was high in both analyses (I² = 94.8% and 96.8%, respectively).

In an odds ratio analysis of 5 studies, SDB presence or greater OSA severity was associated with MASLD or steatosis (OR, 3.62; 95% CI, 1.59-8.25; P ≈ .002). Because that estimate mixed adjusted and unadjusted data, as well as presence and severity comparisons, the authors characterized it as a hypothesis-generating association.

“Sleep-disordered breathing is associated with a significant burden of steatosis and increased odds of MASLD in various populations,” the authors wrote. “It is noteworthy that hypoxemia-related parameters appear to be more consistently associated with liver injury than apnea frequency, indicating the potential role of the former as a factor of MASLD development and progression.”

Findings on fibrosis were less consistent. In one biopsy-based cohort, moderate-to-severe OSA was independently associated with advanced fibrosis (OR, 3.48; 95% CI, 1.03-11.83; P = .045). Qualitatively, nocturnal hypoxemia measures, such as oxygen desaturation index, were more strongly associated with liver damage than the apnea-hypopnea index.

CPAP Improves Liver Enzymes, Not Liver Structure

In pooled before-and-after analyses, CPAP was associated with reductions in alanine aminotransferase (ALT) (mean difference, −7.15 U/L; 95% CI, −9.50 to −4.80; 7 studies) and aspartate aminotransferase (mean difference, −3.38 U/L; 95% CI, −4.45 to −2.30; 6 studies). Most contributing studies were nonrandomized, and the authors noted that aminotransferases are surrogate markers.

Two randomized, controlled analyses did not show significant improvements in steatosis, metabolic dysfunction-associated steatohepatitis, or fibrosis-related measures. The authors pointed to short follow-up, variable CPAP adherence, and small samples as possible explanations. They also cited Mendelian randomization studies that did not establish a causal effect of sleep apnea on MASLD.³

Study Limitations and Screening Implications

Heterogeneity ranged from high to very high (I² = 84.1%-96.8%), and the review did not include subgroup, meta-regression, or leave-one-out sensitivity analyses.¹ Outcome definitions varied from biopsy to ultrasound to ALT-based suspected MASLD, and publication bias was not formally assessed. Additionally, confounding by obesity could not be fully separated from SDB effects. “Pooled point estimates should be viewed as indicative rather than precise,” the authors explained.

They suggested liver assessment be considered in patients with OSA or SDB, particularly those with obesity, metabolic syndrome, diabetes, elevated aminotransferases, or significant nocturnal hypoxemia. Patients with MASLD who have features suggestive of sleep apnea should also be screened for sleep disorders, they wrote, and they called for prospective cohorts and randomized trials with standardized sleep and liver measures and long-term follow-up.

“These findings highlight the sleep-disordered breathing as an important factor modifying metabolic liver disease and call for further integrated cardiometabolic management,” the authors concluded.

References

1. Alhajery MA, Alotay AA. Association between sleep-disordered breathing and liver outcomes in steatotic liver disease: a systematic review and meta-analysis. Front Med (Lausanne). 2026;13:1884855. doi:10.3389/fmed.2026.1884855

2. Younossi ZM, Golabi P, Paik JM, Henry A, Van Dongen C, Henry L. The global epidemiology of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH): a systematic review. Hepatology. 2023;77(4):1335-1347. doi:10.1097/HEP.0000000000000004

3. Zhang Z, Li M, Ji G, Zhang L. Causal relationship between sleep apnea and non-alcoholic fatty liver disease: a mendelian randomization study. Eur J Clin Investig. 2024;54(3):e14116. doi:10.1111/eci.14116