In this issue, Kim et al. [5] investigated the contemporary prevalence of SLD, MASLD, MetALD, and ALD in the United States using data from the National Health and Nutrition Examination Survey (NHANES), specifically comparing the prevalence between the pre-pandemic period (from 2017 until March 2020) and the COVID-19 pandemic period (from August 2021 to August 2023). In addition, they assessed the presence of significant fibrosis, advanced fibrosis, and liver cirrhosis using transient elastography, comparing MASLD, MetALD, ALD, and SLD-related fibrosis and cirrhosis between the two periods. In the United States, among individuals aged over 18 years, the weighted age-adjusted prevalence of SLD (cut-off: 285 dB/m) was 35.0% (95% confidence interval [CI] 33.4–36.7). Within this category, the prevalence was 31.9% (95% CI 30.4–33.4) for MASLD, 2.2% (95% CI 1.8–2.6) for MetALD, and 0.8% (95% CI 0.6–1.1) for ALD. SLD prevalence was higher among men and Hispanics. When broken down by subclassification, MASLD was most prevalent among Hispanics followed by non-Hispanic Asians, while MetALD and ALD were more common among non-Hispanic Whites and Hispanics, respectively. Between the pre-pandemic and COVID-19 pandemic periods, there was no significant difference in prevalence of SLD; however, there was a significant increase in the proportion of significant fibrosis and advanced fibrosis in SLD patients during the COVID-19 pandemic compared to the pre-pandemic period. Although not statistically significant, during the COVID-19 pandemic period, an increase in alcohol consumption was associated with an increase in the prevalence of ALD, while the prevalence of MASLD relatively decreased.

A concerning finding from Kim et al.’s research is that nearly one-third of US adults have MASLD. Additionally, MASLD is predicted to become the most rapidly growing contributor to the disease burden associated with adverse liver outcomes, including liver cirrhosis and HCC, in the future [7]. Recently, resmetirom was approved as a treatment for NASH patients with liver fibrosis, but its application remains very limited [8]. Therefore, lifestyle modification is still recognized as the most important treatment to date.

In the United States, a diverse range of ethnicities coexists, and Kim et al. [5] investigated the prevalence of SLD and its subclasses among different racial groups. Particularly, non-Hispanic Asians showed a relatively high prevalence of MASLD, while non-Hispanic Whites and Hispanics had higher proportions of MetALD and ALD. In non-Hispanic Blacks, the prevalence of SLD, as well as its subclasses MASLD, MetALD, and ALD, was consistently low. Several factors can be considered to explain the differences in prevalence among racial groups. Firstly, variations in the PNPLA3 gene contribute to ancestry-related and individual differences in hepatic fat content and susceptibility to nonalcoholic fatty liver disease (NAFLD) [9]. A variant of PNPLA3 (rs738409[G], encoding I148M) was strongly associated with increased hepatic fat levels and hepatic inflammation, increasing susceptibility to NAFLD. This allele was most commonly found in Hispanics and Asians, but less frequently in Africans [10]. Conversely, another variant of PNPLA3 (rs6006460[T], encoding S453I) was associated with lower hepatic fat content in African Americans, the group with the lowest risk of NAFLD [9]. This may explain why African Americans, despite having similar prevalence rates of obesity and insulin resistance, tend to show significantly lower prevalence rates of SLD [10]. Secondly, in American society, non-Hispanic Asians and Blacks often include populations that are underserved in terms of health-related screenings, which may lead to an underestimation of prevalence [11]. This suggests a need for further research into these racial groups.

The COVID-19 pandemic disrupted regular routines and involuntarily led to irregular and unhealthy lifestyle habits. As described by Kim et al. [5], during this period in the United States, people were confined to their homes, leading to a significant reduction in physical activity and an increase in alcohol consumption. In addition, due to the healthcare system’s focus on COVID-19, high-risk patients did not receive adequate monitoring or appropriate treatment. Consequently, there was a significant increase in the occurrence of fibrosis associated with SLD progression. This not only underscored the critical importance of lifestyle modifications in the management of SLD but also highlighted the necessity of a multidisciplinary approach, including appropriate healthcare system interventions and the establishment of relevant legislation. Historically, pandemics have occurred repeatedly. Given this, it seems prudent to establish strategies in advance for effectively managing SLD patients during future pandemics, taking lessons from the COVID-19 pandemic.