Independent Association of Physical Activity with Nonalcoholic Fatty Liver Disease and Alanine Aminotransferase Levels

Adherence to a healthy lifestyle including sleep and sedentary behaviors and risk of metabolic dysfunction-associated steatotic liver disease in Chinese adults

OBJECTIVE

Various lifestyle factors including smoking, alcohol, physical activity, sedentary behavior, diet quality, sleep behavior, and overweight have been related to metabolic dysfunction-associated steatotic liver disease (MASLD); however, their joint impact on risk of MASLD is not well known. We prospectively investigated the association between a combination of lifestyle factors and risk of MASLD.

METHODS

This prospective cohort study included 13,303 participants (mean age: 39.1 ± 11.3 years, female: 60.1%) in China. A novel healthy lifestyle score was created combining seven healthy factors: not smoking, no alcohol intake, regular physical activity, short sedentary time, healthy diet, healthy sleep, and healthy weight. Incident MASLD cases were ascertained annually by liver ultrasound and cardiometabolic risk factors. Multivariable Cox proportional hazards regression models were used to estimate the association of healthy lifestyle score with risk of MASLD.

RESULTS

Within 48,036 person-years of follow-up, 2823 participants developed MASLD. After adjusting for age, sex, education, occupation, household income, personal and family history of disease, and total energy intake, compared with participants with 0-2 healthy lifestyle factors, the multivariable hazard ratios (95% confidence interval) of MASLD were 0.81 (0.73, 0.89), 0.67 (0.61, 0.75), and 0.55 (0.49, 0.62) for healthy lifestyle score of 3, 4, and 5-7, respectively (P for trend <0.0001). Such associations were consistent across subgroup and sensitivity analyses.

CONCLUSION

Our results indicate that a higher healthy lifestyle score is associated with a lower risk of MASLD.

Diagnostic significance of alanine aminotransferase isoenzymes in alcoholic and non-alcoholic fatty liver cancers

OBJECTIVES

Alanine aminotransferase (ALT) expression is highly elevated in the serum of patients with hepatocellular carcinoma. However, the role of ALT isoenzymes in the total ALT activity remains unclear. In the present study, we systematically investigated the role of ALT isoenzymes in alcoholic and non-alcoholic fatty liver cancer.

MATERIALS AND METHODS

The expression of ALT1 and ALT2 at the mRNA and protein levels in 25 paired primary liver cancer tissues was detected by reverse transcription quantitative PCR (RT-qPCR), Western blotting, and immunohistochemistry. Serum ALT activity was determined using an automated biochemical analyzer.

RESULTS

The mRNA and protein expression levels of ALT1 and ALT2 were lower in the tissues of alcoholic and non-alcoholic fatty liver cancers than in the paracancerous tissues. Notably, ALT2 was highly expressed in non-alcoholic fatty liver cancer tissues compared with alcoholic fatty liver cancer tissues. Total serum ALT activity was mainly contributed by ALT1 in alcoholic fatty liver cancer, whereas ALT1 contributed only marginally more to the total ALT activity than ALT2 in non-alcoholic fatty liver cancer. ALT2/ALT1 ratio can well discriminate normal control group, alcoholic liver cancer and non-alcoholic liver cancer.

CONCLUSION

ALT1 contributed more to the total ALT activity than ALT2 in both alcoholic and non-alcoholic fatty liver cancer. Serum ALT2 to ALT activity was higher in non-alcoholic fatty liver cancer than that in alcoholic fatty liver cancer. ALT2/ALT1 ratio has some diagnostic significance for alcoholic and non-alcoholic liver cancer.

Higher mortality among lean patients with non-alcoholic fatty liver disease despite fewer metabolic comorbidities

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) can develop in individuals who are not overweight. Whether lean persons with NAFLD have lower mortality and lower incidence of cirrhosis, cardiovascular diseases (CVD), diabetes mellitus (DM) and cancer than overweight/obese persons with NAFLD remains inconclusive. We compared mortality and incidence of cirrhosis, CVD, DM and cancer between lean versus non-lean persons with NAFLD.

METHODS

This is a retrospective study of adults with NAFLD in a single centre from 2012 to 2021. Primary outcomes were mortality and new diagnosis of cirrhosis, CVD, DM and cancer. Outcomes were modelled using competing risk analysis and Cox proportional hazards regression analysis.

RESULTS

A total of 18,594 and 13,420 patients were identified for cross-sectional and longitudinal analysis respectively: approximately 11% lean, 25% overweight, 28% class 1 obesity and 35% class 2-3 obesity. The median age was 51.0 years, 54.6% were women. The median follow-up was 49.3 months. Lean patients had lower prevalence of metabolic diseases at baseline and lower incidence of cirrhosis and DM than non-lean patients and no difference in CVD, any cancer or obesity-related cancer during follow-up. However, lean patients had significantly higher mortality with incidence per 1000 person-years of 16.67, 10.11, 7.37 and 8.99, respectively, in lean, overweight, obesity class 1 and obesity class 2-3 groups respectively.

CONCLUSIONS

Lean patients with NAFLD had higher mortality despite lower incidence of cirrhosis and DM, and similar incidence of CVD and cancer and merit similar if not more attention as non-lean patients with NAFLD.

Bidirectional association between NAFLD and gallstone disease: a systematic review and meta-analysis of observational studies

BACKGROUND

Growing evidence indicates an association between NAFLD and gallstone disease (GD), while some does not support this. The aim of this meta-analysis was to evaluate the bidirectional association between NAFLD and GD.

RESEARCH DESIGN AND METHODS

Five electronic databases were searched from inception to May 2022. The association was analyzed based on the odds ratio (OR) and 95% confidence interval (CI) with Reviewer Manager 5.3.

RESULTS

Ten studies involving 284,512 participants met the criteria for GD predicting the onset of NAFLD. GD patients had a higher incidence of NAFLD (OR:1.48, CI:1.32-1.65, p < 0.00001), especially the incidence of moderate-to-severe NAFLD (OR:1.63; CI:1.40-1.79), with females at a higher risk (OR: 1.84; CI: 1.48-2.29). The inverse association was explored in eight studies involving 326,922 participants. The GD incidence in NAFLD patients was higher (OR:1.71, CI:1.63-1.79, p < 0.00001) and may increase due to female sex (OR: 4.18; CI: 1.21-14.37) and high BMI (OR: 1.80; CI: 1.36-2.56), compared with the non-NAFLD group. Besides, this bidirectional association was also confirmed in the Chinese population.

CONCLUSIONS

The findings supported positive concurrent and bidirectional relationships between NAFLD and GD. Therefore, clinicians may alert the possibility of NAFLD in patients with GD and vice versa.

Association between physical activity and serum liver aminotransferases in Southwestern Iran: A Cross-sectional study

BACKGROUND

The main aim of the present study is to investigate the independent association objectively measured level of physical activity (PA) and serum concentration of liver aminotransferases (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) among seemingly healthy individuals.

MATERIALS AND METHODS

The current secondary study was conducted in the framework of Khuzestan Comprehensive Health Study, a large population-based multicentric cross-sectional study, conducted between 2016 and 2019 on 18,966 individuals living in Khuzestan province, southwestern Iran. International PA Questionnaire was used for evaluating PA levels, and participants were divided into three groups: low, moderate, and high PA, and ALT and AST were compared between these groups.

RESULTS

The mean ± standard deviation age of participants was 38.65 ± 11.40 years. The majority of participants were female (71%). The mean concentration of ALT in total sample was 18.22 ± 13.06 (male: 23.65 ± 16.26 and female: 15.57 ± 10.06), while the mean concentration of ALT in total sample was 19.61 ± 8.40 (male: 22.44 ± 10.03 and female: 18.23 ± 7.08). A statistically significant inverse correlation was found between AST (r = -0.08, P = 0.02) and ALT (r = -0.038, P < 0.001) with total PA score. The mean concentration of ALT was 19.96 ± 13.63 in people with low PA, 17.62 ± 12.31 with moderate PA, and 18.12 ± 13.47 with high PA (P < 0.001). The mean concentration of AST in total sample was 20.37 ± 8.85 in people with low PA, 19.21 ± 8.83 with moderate PA, and 19.75 ± 8.85 with high PA (P < 0.001). The difference between people in different levels of PA in terms of mean concentration of AST was remained significant (P = 0.003); however, the difference for ALT was not remained significant after adjusting potential confounders.

CONCLUSION

The current study based on large sample showed that PA had a statistically negative association with the concentration of liver aminotransferases in the seemingly healthy individuals; however, the observed associations were weak. People in the lowest levels of PA had the highest levels of ALT and AST.

Risk Factors and Prediction Models for Nonalcoholic Fatty Liver Disease Based on Random Forest

Objective

To establish a risk prediction model of nonalcoholic fatty liver disease (NAFLD) and provide management strategies for preventing this disease.

Methods

A total of 200 inpatients and physical examinees were collected from the Department of Gastroenterology and Endocrinology and Physical Examination Center. The data of physical examination, laboratory examination, and abdominal ultrasound examination were collected. All subjects were randomly divided into a training set (70%) and a verification set (30%). A random forest (RF) prediction model is constructed to predict the occurrence risk of NAFLD. The receiver operating characteristic (ROC) curve is used to verify the prediction effect of the prediction models.

Results

The number of NAFLD patients was 44 out of 200 enrolled patients, and the cumulative incidence rate was 22%. The prediction models showed that BMI, TG, HDL-C, LDL-C, ALT, SUA, and MTTP mutations were independent influencing factors of NAFLD, all of which has statistical significance (P < 0.05). The area under curve (AUC) of logistic regression and the RF model was 0.940 (95% CI: 0.870~0.987) and 0.945 (95% CI: 0.899~0.994), respectively.

Conclusion

This study established a prediction model of NAFLD occurrence risk based on the RF, which has a good prediction value.

Joint Effect of Hepatic Steatosis and Alanine Aminotransferase Within the Normal Range on Incident Ischemic Heart Disease: A Prospective Study in Koreans

Purpose

Hepatic steatosis has been associated with some cardiovascular risks. Increased alanine aminotransferase (ALT) was suggested to be linked to endothelial dysfunction. We prospectively investigated the joint effect of hepatic steatosis and elevated ALT within the normal range on incident ischemic heart disease (IHD) risk as an extrahepatic complication.

Patients and Methods

We assessed 16,541 participants without diabetes using data from a health risk assessment study (HERAS) and Korean Health Insurance Review and Assessment (HIRA) data. We defined elevated ALT within the normal range as 30-40 IU/L in men and 23-40 IU/L in women, according to previous Korean epidemiological data. We prospectively assessed hazard ratios (HRs) with 95% confidence intervals (CIs) for IHD using multivariate Cox proportional hazards regression models over a 50-month period after the baseline survey.

Results

During the follow-up period, 368 (2.2%) participants developed IHD. Compared to the group with no hepatic steatosis and controlled ALT, the HRs for IHD were 1.68 (95% CI, 1.16-2.42) in the group with hepatic steatosis and elevated ALT after adjusting for confounding variables.

Conclusion

Hepatic steatosis and elevated ALT levels within the normal range may jointly affect the development of IHD among nondiabetic adults. This indicates that lifestyle advice and vascular health management should be recommended among individuals with hepatic steatosis and elevated ALT, even if it falls within the normal range.

NAFLD and Physical Exercise: Ready, Steady, Go!

Along with the increase in obesity and type 2 diabetes, the non-alcoholic fatty liver disease (NAFLD) incidence is escalating, thus becoming a leading cause of liver cirrhosis and a significant burden of liver-related outcomes. Since there is no pharmacotherapy available to address the NAFLD, the most effective solutions seem to be lifestyle changes centered on physical activity. Exercise could mediate its beneficial effects directly on the liver and indirectly via extrahepatic pathways, forming a dose-response relationship with NAFLD in terms of prevalence and disease severity. Health-enhancing physical activity (HEPA) levels are mainly needed to exert beneficial effects in obese subjects, while even a small amount of exercise can be beneficial for lean individuals to prevent NAFLD. This mini-review addresses three major points regarding physical activity and NAFLD: prevention, treatment, and extrahepatic benefits, offering recommendations on type and intensity of exercise in liver disease.

Aerobic Exercise in the Management of Metabolic Dysfunction Associated Fatty Liver Disease

Sedentarism is the pandemic of modern times. It is associated with several medical conditions including obesity, type 2 diabetes mellitus, cardiovascular diseases and also liver disease, particularly metabolic dysfunction associated fatty liver disease (MAFLD). In an era when MAFLD is the most prevalent chronic liver disease worldwide, whilst no pharmacological therapy has been approved for it, exercise has proved to be effective in improving liver steatosis. Interestingly, exercise decreases liver fat even in the absence of weight loss. The challenge for the clinician is to motivate the obese patient with MAFLD, and associated co-morbidities, who has crystallized a sedentary behavior, at times when every need is at the distance of a click on the Internet, and the entire world can be visited behind a screen. In this review, the aggregate evidence on the mechanisms and effects of exercise in the management of MAFLD is summarized, with simple recommendations for everyday clinical practice.

Trends in the Prevalence of Non-Alcoholic Fatty Liver Disease and Its Future Predictions in Korean Men, 1998-2035

Non-alcoholic fatty liver disease (NAFLD) is a serious health concern as it can progress to liver cirrhosis and hepatoma. We investigated past trends in the prevalence of NAFLD and related factors among Korean men and women from 1998 to 2017 and predicted their future prevalence among Korean men. We used data from the Korea National Health and Nutrition Examination Survey I–VII (KNHANES). NAFLD was defined as a hepatic steatosis index of >36. Subjects with viral hepatitis, liver cirrhosis, cancer, pregnancy, and a habit of drinking ≥30 g alcohol per occasion were excluded. We evaluated the prevalence trends of NAFLD, obesity, abdominal obesity, high fat intake, and low physical activity in each KNHANES wave. For future prevalence predictions, average annual percentage changes (AAPCs) were estimated from the joinpoint model. In men, NAFLD prevalence has increased by approximately 11 percentage points in the past 19 years, reaching 30.7% in wave VII. Prevalence of obesity, abdominal obesity, high fat intake, and low physical activity also increased. The AAPC of NAFLD prevalence was 2.3% per year, and the estimated NAFLD prevalence in 2030 and 2035 was 39.1% and 43.8%, respectively. The forecasted prevalence of obesity, abdominal obesity, and high fat intake among Korean men in 2035 was 65.0%, 52.2%, and 23.5%, respectively. The estimated future prevalence of NAFLD and related factors was considerably high in the younger age group (19–45 year). In women, NAFLD prevalence has increased by approximately three percentage points in the past 19 years; however, this increase was not significant in the multivariate analysis. Public strategies to manage obesity, abdominal obesity, and unhealthy lifestyles are needed to prevent NAFLD.