Cancer disparities in lean vs. non-lean MASH: insight from a national inpatient sample

Objective To investigate cancer disparities between lean (BMI < 25 kg/m²; < 23 kg/m² for Asians) and non-lean metabolic dysfunction-associated steatohepatitis (MASH) by analyzing the prevalence of the 18 most common cancers in a large U.S. cohort. Methods This retrospective cohort study utilized the National Inpatient Sample (2016–2020) with weighted data to project findings to the general population. Patients were categorized as lean or non-lean based on BMI during hospitalization, excluding alternative etiologies via validated algorithms. Outcomes included composite cancer prevalence (primary) and individual cancer prevalence (secondary). Multivariable logistic regression was applied to assess differences. Results Among 34,955,252 U.S. hospitalizations, 539,275 patients had MASH (mean age: 64 years for lean vs. 58.8 years for non-lean; >60% female). Lean MASH hospitalizations had higher odds of lung (aOR 1.76, CI 1.33–2.10, P < 0.001), colon (aOR 1.23, CI 1.02–1.48, P = 0.027), kidney (aOR 1.27, CI 1.10–1.44, P = 0.001), liver (aOR 1.21, CI 1.12–1.31, P < 0.001), and cervical cancers (aOR 3.25, CI 1.07–9.86, P = 0.037), as well as non-Hodgkin’s lymphoma (aOR 1.28, CI 1.08–1.51, P = 0.004), but lower odds of endometrial cancer (aOR 0.35, CI 0.25–0.50, P < 0.001). Conclusion Lean MASH hospitalizations are linked to higher odds of several cancers despite lower BMI, underscoring the need for a nuanced understanding of cancer risks in MASH. BMI alone may not fully capture oncologic risk in this population.