Effects of physical activity and diet quality on the prevalence and characteristics of obese and non-obese MAFLD in a US population

Background: Clinical data on the prevalence of metabolic-associated fatty liver disease (MAFLD) in obese and non­­-obese patients in a multi-ethnic US population are limited Additionally, the effects of physical activity and diet quality on the risk of MAFLD remain unclear. We aimed to investigate the prevalence and clinical characteristics of MAFLD and the associations of physical activity (PA) and diet quality (DQ) with MAFLD risk. Methods: : This cross-sectional study was conducted using the 2017–2018 NHANES databases. Overall, 5,533 participants with fatty liver disease identified by ultrasound were categorized into the non-MAFLD, obese-MAFLD, and non-obese-MAFLD groups. Results: : The overall prevalence of MAFLD among the participants was 41.9%; 28.6% of all the participants were obese and 13.4% were non-obese. Among those with MAFLD, 67.1% (95% confidence interval (CI): 59.1%–75.1%) were obese and 32.9% (95% CI: 29.1%–36.7%) were non-obese. Obese and non-obese MAFLD were more common in participants aged 50–64 years (31.8% and 34.1%, respectively; p < 0.0001) and in men (30.6% vs. 16.4%, respectively). Non-obese MAFLD was more common in Asians (27.2%), while obese MAFLD was more common in Blacks (66.3%). Metabolic comorbidities were more common in those with obese MAFLD who also had more advanced fibrosis. High-quality diet (HQD) and increased PA were associated with reduced odds of developing obese and non-obese MAFLD (odds ratio (OR) and 95% CI: 0.67 [0.51–0.88] and 0.57 [0.47–0.69]; 0.62 [0.43–0.90] and 0.63 [0.46–0.87], respectively). PA and a HQD significantly lowered the risk for obese and non-obese MAFLD (OR and 95% CI: 0.46 [0.33–0.64] and 0.42 [0.31–0.57]). Conclusion: Individuals with obese and non-obese MAFLD accounted for a high proportion of the US population. HQD and PA were strongly associated with a lower risk for MAFLD.