Trends in metabolic dysfunction-associated steatotic liver disease by household income, 2007–2022: A national representative study in South Korea

Metabolic dysfunction-associated steatotic liver disease (MASLD) could lead to liver-related life-threatening conditions. However, relatively little research has been conducted on trends in MASLD based on household income. This study aimed to examine trends in MASLD prevalence stratified by household income and identify socioeconomic factors associated with a risk of MASLD. Data from the Korea National Health and Nutrition Examination Survey from 2007 to 2022 were analyzed to examine MASLD prevalence among adults in South Korea, stratified by household income levels. Household income was categorized into quartiles, and covariates including sex, age, region of residence, education level, stress level, smoking status, and drinking status were assessed. Weighted prevalence estimates were calculated to assess trends in MASLD across the study period. In addition, logistic regression models were applied to estimate adjusted odds ratios with 95% confidence intervals (CIs), comparing pre-pandemic and pandemic periods as well as across income quartiles stratified by sex, age, and other covariates. A total of 70,276 individuals aged ≥19 years (male: 29,169 [41.51%]) from 2007 to 2022 were included in the analysis. MASLD prevalence increased over the study period across all household income levels. Particularly, in the medium-high and high household income levels, prevalence increased from 16.30% (95% CI, 14.83-17.76) in 2007 to 27.25% (95% CI, 24.46-30.04) in 2022 and from 15.15% (95% CI, 13.71-16.58) in 2007 to 25.44% (95% CI, 22.01-28.86) in 2022, respectively. The prevalence of MASLD exhibited a sex-specific trend, being higher among low-income females while tending to be higher among high-income males. Males, middle-aged individuals, high-stress levels, and smoking status were identified as risk factors for MASLD. This is the first study to analyze the trends of MASLD stratified by household income level in South Korea. These findings offer insights that may facilitate the identification of priority populations and guide the development of equity-focused public health strategies.