Physical Activity Identified as Critical Factor in Lowering MAFLD Risk

A new study revealed physical activity was the most critical lifestyle factor influencing Metabolic Associated Fatty Liver Disease (MAFLD).¹ Other lifestyle factors, such as sleep duration and diet, also had associations with Metabolic Associated Fatty Liver Disease. The study suggests interactions between these lifestyle factors are important to consider when determining an individual’s overall MAFLD risk.

“This study provides further evidence on lifestyle and MAFLD, showing that increasing physical activity, improving diet, and increasing sleep duration can reduce the risk of MAFLD,” wrote investigators, led by Sicheng Li, from Xiamen Cardiovascular Hospital of Xiamen University, in China.

Previous research demonstrated links between single lifestyle exposures and MAFLD. Yet, the combined effects of lifestyle factors needed to be clarified. A 2023 study examined joint lifestyle factors but assumed the different factors had equal weight.² In this study, investigators aimed to assess the associations between joint lifestyle exposomes and MAFLD.¹

The cross-sectional study included 5002 participants from NHANES 2017 – 2020. In total, 37.2% had MAFLD. The sample had a mean age of 50.43 years, majority female (52.04%). Most of the participants were non-Hispanic White (37.78%), followed by non-Hispanic Black (26.09%), Mexican American (11.26%), non-Hispanic Asian (10.28%), other Hispanic (9.68%), and other (4.92%).

Lifestyle exposomes were collected from questionnaires and included sleep duration, metabolic equivalent of task (MET), Healthy Eating Index (HEI)-2015 score, alcohol consumption, and smoke exposure. The MET was calculated from the participant’s type, frequency, and exercise duration.

Participants were diagnosed with MAFLD by vibration-controlled transient elastography measurements and laboratory data. MAFLD was defined as the presence of hepatic steatosis (CAP ≥ 285 dB/m (0.8 sensitivity and 0.77 specificity) with 1 of the following: overweight or obesity (body mass index: ≥ 25 kg/m2, diabetes mellitus, and ≥ 2 metabolic risk abnormalities.

Compared to participants without MAFLD, those with MAFLD tended to be older (53.26 years vs 48.75 years), predominantly male (55.36% vs 44.76%), had lower educational attainment (6.13% vs 4.74%), reported shorter sleep duration (7.63 vs 7.78 hours), engaged in less physical activity (69.51 hours per week vs 80.39 hours per week), had less nutritious diets (49.77 vs 50.89 HEI – 2015), and had a greater likelihood of smoke exposure (57.60 vs 53.77) and alcohol use (6.06 vs 5.76 g/day).

Investigators assessed the association of single and joint lifestyle factors using logistic regression and the weighted quantile sum method, respectively.

Investigators found per-quartile range increases in sleep duration (odds ratio [OR], 0.883; 95% confidence interval [CI], 0.826 – 0.944; P < .001), MET (OR, 0.916; 95% CI, 0.871 – 0.963; P = .001), and HEI- 2015 score (OR, 0.827; 95% CI, 0.756 – 0.904; P < .001) were negatively significantly associated with MAFLD. Moreover, smoke exposure (OR, 1.067; 95% CI, 0.939 – 1.213; P = .318) and alcohol consumption (OR, 1.001; 95% CI, 0.985 – 1.016; P = .967) demonstrated positive associations with MAFLD, but these associations were not statistically significant.

The sensitivity analysis demonstrated greater intervention benefits for sleep and HEI-2015 when > 5% of the minority population had a low MAFLD risk, which indicates these 2 are weaker intervention targets. Conversely, MET was the most efficient intervention strategy when only ≤ 5% of the minority population had low MAFLD risk, Therefore, when more people had a greater MAFLD risk, MET was more efficient, suggesting this is a strong intervention target.

“In subgroup analyses, we observed a stronger effect of joint exposure among highly educated individuals and Mexican Americans than among those with less education and non-Hispanic Whites,” investigators wrote. “Although the exact underlying mechanism remains unclear, we hypothesize that unmeasured lifestyle factors might explain this disparity.”

Multi-exposure analyses revealed the combined exposure of sleep duration, MET, and HEI-2015 score was linked to MAFLD (OR, 0.772; 95% CI, 0.688 – 0.65). However, among the 3 factors, MET had the most influence on the reduced risk of MAFLD with an estimated weight of 0.526, greater than the weights of the HEI-2015 (0.263) and sleep duration (0.211) score, as found in the WQS analysis. The estimated weights in the QGC analysis were 0.385, 0.310, and 0.305 for MET, HEI-2015, and sleep duration scores, respectively, suggesting the importance of physical activity as a critical lifestyle exposure.

“The results of [population attributable fractions] analysis and categorical multiple-exposure analysis in this study only represent the effect of a single lifestyle intervention, and subsequent studies should estimate the effect of multiple-exposure joint interventions combined with health economics methods to provide the best recommendations for joint intervention strategies,” investigators concluded.

References

1. ^{Li S, Chen J, Zhang Y, et al. Identifying the most critical behavioral lifestyles associated with MAFLD: evidence from the NHANES 2017-2020. Front Endocrinol (Lausanne). 2024;15:1375374. Published 2024 Jul 25. doi:10.3389/fendo.2024.1375374}
2. ^{Wang X, Wang A, Zhang R, Cheng S, Pang Y. Life's Essential 8 and MAFLD in the United States. J Hepatol. 2023;78(2):e61-e63. doi:10.1016/j.jhep.2022.10.014}