Natural course of fatty liver in 36,195 South Korean adults

Physical Activity and Nonalcoholic Fatty Liver Disease: A Roundtable Statement from the American College of Sports Medicine

ABSTRACT

Although physical activity (PA) is crucial in the prevention and clinical management of nonalcoholic fatty liver disease, most individuals with this chronic disease are inactive and do not achieve recommended amounts of PA. There is a robust and consistent body of evidence highlighting the benefit of participating in regular PA, including a reduction in liver fat and improvement in body composition, cardiorespiratory fitness, vascular biology, and health-related quality of life. Importantly, the benefits of regular PA can be seen without clinically significant weight loss. At least 150 min of moderate or 75 min of vigorous intensity PA are recommended weekly for all patients with nonalcoholic fatty liver disease, including those with compensated cirrhosis. If a formal exercise training program is prescribed, aerobic exercise with the addition of resistance training is preferred. In this roundtable document, the benefits of PA are discussed, along with recommendations for 1) PA assessment and screening; 2) how best to advise, counsel, and prescribe regular PA; and 3) when to refer to an exercise specialist.

Effect of physical activity on the development and the resolution of nonalcoholic fatty liver in relation to body mass index

Background

Data on whether physical activity (PA) levels are related to nonalcoholic fatty liver disease (NAFLD) when considering body mass index (BMI) are scarce. We assessed whether PA affects the development or resolution of NAFLD in conjunction with BMI changes.

Methods

Overall, 130,144 participants who underwent health screening during 2011–2016 were enrolled. According to the PA level in the Korean version of the validated International PA Questionnaire Short Form, participants were classified into the inactive, active, and health-enhancing PA (HEPA) groups.

Results

In participants with increased BMI, the hazard ratio (HR) and 95% confidence interval after multivariable Cox hazard model for incident NAFLD was 0.97 (0.94–1.01) in the active group and 0.94 (0.89–0.99) in the HEPA group, whereas that for NAFLD resolution was 1.03 (0.92–1.16) and 1.04 (0.88–1.23) (reference: inactive group). With increased BMI, high PA affected only new incident NAFLD. PA enhancement or maintenance of sufficient PA prevented new incident NAFLD. In participants with decreased BMI, the HRs were 0.98 (0.90–1.07) and 0.88 (0.78–0.99) for incident NAFLD and 1.07 (0.98–1.17) and 1.33 (1.18–1.49) for NAFLD resolution in the active and HEPA groups, respectively. With decreased BMI, high PA reduced incident NAFLD and increased NAFLD resolution. Maintenance of sufficient PA led to a considerable resolution of NAFLD.

Conclusion

In this large longitudinal study, PA prevented incident NAFLD regardless of BMI changes. For NAFLD resolution, sufficient PA was essential along with BMI decrease. Maintaining sufficient PA or increasing the PA level is crucial for NAFLD prevention or resolution.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-13128-6.

Relationship between triglyceride glucose index and the incidence of non-alcoholic fatty liver disease in the elderly: a retrospective cohort study in China

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) is one of the major causes of liver-related diseases but relationship between triglyceride glucose (TyG) and NAFLD in the elderly is not reported yet. In this study, we investigated the role of TyG index for predicting the incidence of NAFLD in the elderly.

DESIGN AND SETTING

This is a prospective cohort study in Henan, China, from 2011 to 2018.

PARTICIPANTS AND METHODS

In total, 46 693 elderly who participated in a routine physical examination programme from 2011 to 2018 were included in this study. TyG index was calculated as ln (fasting triglyceride (mg/dL)×fasting plasma glucose (mg/dL)/2), while NAFLD was defined as hepatic steatosis after excluding other causes based on the results of abdominal ultrasonography; Cox regression model was performed to explore the relationship between TyG index and NAFLD. Also, mediation effect was used to analyse the role of the TyG index in WHtR (waist-to-height ratio) and NAFLD.

RESULTS

During the 149 041 person-years follow-up, a total of 5660 NAFLD events occurred (3.80/100 person-years). After adjusting for potential confounding factors, quartiles 4 of TyG index significantly increased the incidence of NAFLD compared with quartile 1, the HRs and 95% CI were 1.314 (1.234 to 1.457). In addition, TyG index played a partial mediating role in the relationship between WHtR and NAFLD and indirect effect was 1.009 (1.006 to 1.011).

CONCLUSION

Higher TyG index was associated with higher risk of NAFLD in the aged, and therefore, TyG index may be a novel predictor for incidence of NAFLD. Further, regular examination and evaluation of the TyG index might be useful for controlling the occurrence of NAFLD.