Trends in prevalence and all-cause mortality of metabolic dysfunction-associated fatty liver disease among adults in the past three decades: Results from the NHANES study

Abstract

Background: Given the escalating epidemic of obesity and diabetes coupled with redefined diagnostic criteria, it is critical to identify the prevalence of metabolic dysfunction-associated fatty liver disease (MAFLD). We sought to determine the prevalence and mortality outcomes of MAFLD subtypes based on diagnostic criteria in the USA over the past three decades.

Methods: Eleven cycles of the National Health and Nutrition Examination Surveys (NHANES; 1988-1994 and 1999-2020) were used, and 72,224 participants were included. MAFLD was defined according to the 2020 International Expert Consensus. Based on diagnostic criteria and risk factors, MAFLD was categorized into seven subtypes: type 1 (obesity subtype), 2 (metabolic unhealthy subtype), 3 (diabetes subtype), 4 (metabolic unhealthy non-diabetes subtype), 5 (obesity and diabetes subtype), 6 (metabolic unhealthy non-obesity subtype), and 7 (mixed subtype).

Results: Over the study period, the estimated prevalence of MAFLD increased significantly from 22% in 1988-1994 to 36% in 2017-2020. The prevalence of Type 4 was the highest, followed by that of Type 7, whereas other types were low and almost unchanged over time. Individuals with MAFLD had 19% and 38% increased mortality risks from all causes and cardiovascular disease, respectively. Among them, the metabolically unhealthy participants with normal weight demonstrated a 116% higher risk for all-cause mortality [hazard ratio (HR): 2.16, 95% CI: 1.52-3.08] and a 222% higher risk for cardiovascular mortality (HR: 3.22, 95% CI: 1.72-6.04). Interestingly, stratification and interaction analyses demonstrated a significant impact of metabolic parameters on the relationship between MAFLD and all-cause mortality.

Conclusions: In conclusion, our study identified an increase in MAFLD prevalence and a significant association between metabolic derangements in MAFLD and all-cause or cardiovascular mortality.

Keywords: All-cause mortality; Cardiovascular mortality; Metabolic dysfunction-associated fatty liver disease; Prevalence; Subtypes.