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Editor's note
Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common liver disease worldwide. Recent data show that the incidence is as high as 39% in adults and 20% in children. MAFLD is characterized by overweight or obesity, type 2 diabetes mellitus, and/or metabolic dysregulated hepatic steatosis, which may coexist with a variety of hepatic and cardiometabolic diseases.
It is important to note that patients with MAFLD have a higher risk of cardiovascular disease and overall mortality, and may have a worse disease prognosis. With the increasing prevalence, health burden, and socioeconomic burden of MAFLD, the need for new lifestyles is increasing, and patients with MAFLD are increasingly in need of multidisciplinary care to maintain a healthy lifestyle. In addition, because there are multiple subtypes of MAFLD, there is a need to add individualized specialist care.
Recently, the journal Hepatology International published a review article on lifestyle interventions for MAFLD. Investigators combine past and recent evidence to provide clinical guidance for lifestyle management of MAFLD in adults. The investigators also aim to explore effective approaches to lifestyle interventions in contemporary MAFLD through the specific lens of a "24-hour" integrated lifestyle intervention, including diet, exercise, sedentary behavior, substance use, and sleep.
Goals of lifestyle interventions
Researchers note that improving the quality of diet, increasing exercise, reducing or abstaining from alcohol consumption, and quitting smoking have multiple benefits for the liver and body. Lifestyle interventions can stop the progression of MAFLD, prevent severe liver damage, histologically reverse MAFLD, and reduce the incidence of hepatocellular carcinoma. In addition, lifestyle interventions can reduce the risk of cardiometabolic diseases and reduce cardiovascular morbidity and mortality.
From a patient-centered perspective, improving quality of life is the primary goal of lifestyle interventions. Lifestyle intervention management should be carried out by a multidisciplinary care team (including physicians, dietitians, exercise professionals, psychologists, caregivers, and other allied health professionals).
Weight management
Metabolic dysfunction of MAFLD is closely related to excess and dysfunction of adipose tissue, so weight loss, especially fat, is central to the management of MAFLD. The magnitude of weight loss was directly proportional to improvements in liver-related outcomes. Current guidelines recommend weight loss of ≥5% to reduce hepatic steatosis, ≥7% to alleviate steatohepatitis, and ≥ 10% to resolve fibrosis.
However, the goal of ≥7%~10% weight loss is often difficult to achieve and maintain, and less than one-third of MAFLD patients lose ≥5% of their body weight through lifestyle interventions within 52 weeks. In addition, 5%~10% of MAFLD patients had a normal body mass index (BMI, kg/m2; The incidence was highest in middle-aged people < 25 kg/m2 in the Western population and <23 kg/m2 in the Asian population, and in Asian countries. For lean MAFLD patients, a weight loss of 3%~5% can regress 50% of MAFLD and improve cardiometabolism.
With or without weight loss, lifestyle interventions have health benefits. A 30% reduction in hepatic steatosis was associated with an increase in ≥ MAFLD activity score and was clinically significant. There is a strong correlation between weight loss and a reduction in hepatic steatosis, and with lifestyle interventions, a relative reduction of ≥30% in hepatic steatosis and an average weight loss of ≤5% can be observed. Therefore, weight management should be accompanied by appropriate behavioral strategies that emphasize health goals beyond weight loss and are tailored to the patient's performance, abilities, and preferences.
Diet management and smoking
Currently, clinical management guidelines, including large international associations, include dietary recommendations for MAFLD. All guidelines caution against alcohol consumption because it can affect the progression of fibrosis and end-stage liver disease, and recommend alcohol consumption below the risk threshold (20 g/day for women and 30 g/day for men) or abstinence, particularly in patients with severe fibrosis (>F2) and/or moderate to heavy alcohol consumption.
In terms of diet, it is recommended to prioritize weight loss through caloric restriction and strengthen the intake of anti-inflammatory and antioxidant diets to control the onset and progression of the disease.
In addition, smoking is a recognized risk factor for a variety of chronic diseases, including cardiovascular disease and malignancy, which are common causes of morbidity and mortality in MAFLD. Smoking is associated with advanced fibrosis in chronic liver disease, such as chronic viral hepatitis. There are also studies that suggest a dose-dependent relationship between smoking and the stage of liver fibrosis in patients with MAFLD. In fact, a recent study in Spain also showed that smoking also increased the overall mortality rate of MAFLD patients.
Exercise management
Physical activity (PA) and sedentary behavior are associated with the development of MAFLD. The increase in PA was dose-dependent with a decrease in the risk of MAFLD. In UK Biobank, the risk of MAFLD is 61% lower in the top quartile of PAs than in the bottom quartile of PAs. In addition, increased steps per day were associated with a reduced probability of MAFLD and liver disease progression. Higher amounts of PA may limit the expression of genetic risk factors (PNPLA3, rs738409) for progressive MAFLD. Sedentary behavior and sedentary time are also independent predictors of MAFLD and exhibit a dose-dependent relationship, with an additional 1 hour per day increasing the likelihood of developing MAFLD by 4%.
Individuals who were sedentary for ≥ 7 hours per day were 34% more likely to develop MAFLD than those who ≤ 4 hours per day. In addition, sitting for ≥ 8 hours per day may increase the risk of MAFLD, regardless of PA levels. In addition to preventing the occurrence of MAFLD, moderately vigorous PA is also associated with the resolution of MAFLD. In a large adult cohort, 35% of baseline MAFLD cases (n=42 536) resolved at 5-year follow-up. After adjusting for BMI and other potential confounders, moderate to vigorous PA was associated with regression of MAFLD, with the greatest benefit when PA frequency ≥ 5 days per week. Worryingly, compared with non-MAFLD patients, MAFLD patients are sedentary for a longer time and are less likely to meet the recommended physical activity guidelines, with up to 75%~80% of MAFLD patients underactive in physical activity.
Sleep management
Few studies have investigated the effects of sleep quality and sleep duration on MAFLD. A review of five cross-sectional studies and one cohort study showed a 19% increased risk of MAFLD in participants with short sleep duration (<5~6 hours). This observation was confirmed by a larger cohort study, with a mean follow-up of four years. Compared with non-MAFLD patients, patients with MAFLD sleep less efficiently, taking more frequent daytime naps (> 30 minutes), using sleeping pills more often, and waking up and going to bed later.
Although the data shows that achieving 7~8 hours of optimal sleep and reducing daylight hours can help prevent MAFLD. However, the effects of sleep on inflammatory processes, hormone-driven appetite regulation, metabolism, and the effects of fatigue on physical activity and dietary choices warrant further investigation.
Summary and outlook
Weight loss ≥7%~10% is the core goal of lifestyle intervention; However, even without losing weight, you can benefit from it by improving the quality of your diet and exercising.
Lifestyle interventions for MAFLD should consider a "24-hour" approach, which incorporates the management of diet, physical activity/exercise, sedentary behavior, smoking, alcohol consumption, and sleep (see Figure 1). Dietary management focuses on inadequate energy intake and improving the quality of the diet, with a particular focus on promoting the Mediterranean diet, but its practical application should take into account different dietary cultures.
Figure 1. Recommendations for 24-hour integrated lifestyle behavior management for MAFLD
(Image from the literature)
Increasing physical activity and reducing sedentary behavior can prevent MAFLD. The strongest evidence recommends 150~240 minutes of moderate-intensity aerobic exercise per week. For people who have lost weight through dietary and/or pharmacological methods, as well as those with sarcopenia, resistance training in addition to aerobic exercise should be prioritized to reduce bone and muscle loss. Limited evidence suggests that sleep is important for the prevention of MAFLD.
The investigators point to the need for large-scale, multidisciplinary trials and long-term follow-up of patients with MAFLD in order to expand this 24-hour comprehensive lifestyle behavior management recommendation to basic health care. In addition, future MAFLD management guidelines should take into account the heterogeneity of MAFLD and individualized care models to better manage the increasing number of MAFLD patients.
原文链接：Keating,S.E.,Chawla,Y.,De,A.et al. Lifestyle intervention for metabolic dysfunction-associated fatty liver disease: a 24-h integrated behavior perspective. Hepatol Int (2024). https://doi.org/10.1007/s12072-024-10663-9
Source: Editorial Board of International Liver Disease