Dose-response relationships of accelerometer-measured sedentary behaviour and physical activity with non-alcoholic fatty liver disease

Association of physical activity and sports participation with insulin resistance and non-alcoholic fatty liver disease in people with type 1 diabetes

AIM

To evaluate the association between physical activity (PA) and sports participation with insulin resistance and non-alcoholic fatty liver disease (NAFLD) in people with type 1 diabetes (T1D).

METHODS

People with T1D from a secondary and tertiary care centre were included. Questionnaire-derived PA was expressed in metabolic equivalent of task hours per week (METh/week). Insulin sensitivity was calculated with the estimated glucose disposal rate (eGDR). NAFLD was assessed by transient elastography (TE). Multivariate linear and logistic regression models were conducted, adjusted for age, sex, diabetes duration and BMI.

RESULTS

In total, 254 participants were included (men 56%, age 44 ± 14 years, diabetes duration 24 ± 14 years, median BMI 24.8 kg/m2), of which 150 participants underwent TE. Total PA (median 50.7 METh/week) was not significantly associated with insulin resistance (median eGDR 7.31 mg/kg/min) (beta -0.00, 95% CI -0.01 to 0.00) or with NAFLD (OR 1.00, 95% CI 0.99-1.01). Participating in sports was significantly associated with eGDR (beta 0.94, 95% CI 0.48-1.41) and with NAFLD (OR 0.21, 95% CI 0.08-0.56).

CONCLUSIONS

In our T1D population, we could not find any dose-dependent association between PA, insulin resistance and NAFLD. People participating in sports had a lower degree of insulin resistance and lower odds for NAFLD.

Usefulness of Neck Circumference, Waist-to-Height Ratio and Waist-to-Hip Ratio in Predicting Non-Alcoholic Fatty Liver Disease in Saudi Population Without Type 2 Diabetes

Background

Early identification and treatment of non-alcoholic fatty liver disease (NAFLD) could reduce overall mortality. Anthropometric measurements offer a simple and cost-effective method to potentially improve early detection of NAFLD and prevent its complications. This study aims to estimate the prevalence of NAFLD using the fatty liver index (FLI) and evaluate the effectiveness of certain anthropometric measurements in predicting NAFLD as diagnosed by FLI.

Method

A cross-sectional analytical study was conducted with 1264 Saudi population without Type 2 diabetes mellitus (T2DM) non-alcoholic individuals at primary health care centers (PHCCs) in Jeddah city. Measurements included triglycerides, gamma-glutamyl transferase (GGT), glycated hemoglobin (HbA1c), and fasting plasma glucose (FPG). Measurements for neck circumference (NC), and calculations for weight-to-height ratio (WHtR) and weight-to-hip ratio (WHpR), along with FLI, were performed. NAFLD was identified in individuals with an FLI ⩾60. The receiver operating characteristic (ROC) curve analysis was utilized to assess the accuracy of WHtR, WHpR, and NC in detecting NAFLD, with Youden's index determining the optimal cutoff points for these 3 indices.

Result

The prevalence of NAFLD was found to be 30.9%. Among the markers, WHtR emerged as the most significant in indicating NAFLD, achieving an area under the curve (AUC) of 0.916; whereas NC and WHpR exhibited identical AUC values of 0.783. WHtR demonstrated superior diagnostic efficacy for identifying elevated FLI, with gender-specific cutoff values established at >0.57 for females and >0.61 for males. In all 3 markers, females exhibited higher sensitivity, specificity, and negative predictive value (NPV) compared to males.

Conclusion

WHtR could serve as a useful tool in the initial clinical screening for NAFLD among Saudi population without T2DM to identify those who may benefit from more comprehensive testing. Further local studies are warranted to confirm the levels of accuracy and the calculated cutoffs.

Exercise improves surrogate measures of liver histological response in metabolic dysfunction-associated steatotic liver disease

BACKGROUND AND AIMS

Exercise is recommended for the management of metabolic dysfunction-associated steatotic liver disease (MASLD), yet effects on liver histology remain unknown, especially without significant weight loss. We aimed to examine changes in surrogate measures of liver histological response with exercise training.

METHODS

We conducted a post hoc pooled analysis of three randomised controlled trials (duration: 12-20 weeks) comparing aerobic exercise interventions with controls. The primary outcome measure was a ≥30% relative reduction in (MRI-measured) liver fat, as a surrogate measure of liver histological response (the threshold necessary for fibrosis improvement). Secondary outcome measures were changes in other biomarkers of liver fibrosis, anthropometry, body composition and aerobic fitness.

RESULTS

Eighty-eight adults (exercise: 54, control: 34; male: 67%) were included with mean (SD) age 51 (11) years and body mass index 33.3 (5.2) kg/m2. Following the intervention, exercise had ~5-fold (OR [95%CI]: 4.86 [1.72, 13.8], p = .002) greater odds of ≥30% relative reduction in MRI-measured liver fat compared with control. This paralleled the improvements in anthropometry (waist and hip circumference reduction), body composition (body fat, visceral and subcutaneous adipose tissue) and aerobic fitness (V̇O2peak, ventilatory threshold and exercise capacity). Importantly, these effects were independent of clinically significant body weight loss (<3% body weight).

CONCLUSION

Exercise training led to clinically meaningful improvements in surrogate serum- and imaging-based measures of liver histological change, without clinically meaningful body weight reduction. These data reinforce the weight-neutral benefit of exercise training and suggest that aerobic training may improve liver fibrosis in patients with MASLD.

A public health perspective on mitigating the global burden of chronic liver disease

Chronic liver disease is a significant global health problem. Epidemiological trends do not show improvement in chronic liver disease incidence but rather a shift in etiologies, with steatotic liver disease (SLD) from metabolic dysfunction and alcohol becoming increasingly important causes. Consequently, there is a pressing need to develop a comprehensive public health approach for SLD. To that end, we propose a public health framework for preventing and controlling SLD. The framework is anchored on evidence linking physical inactivity, unhealthy dietary patterns, alcohol use, and obesity with both incidence and progression of SLD. Guided by the framework, we review examples of federal/state-level, community-level, and individual-level interventions with the potential to address these determinants of SLD. Ultimately, mitigating SLD's burden requires primary risk factor reduction at multiple socioecological levels, by scaling up the World Health Organization's "best buys," in addition to developing and implementing SLD-specific control interventions.

The association between reallocations of time and health using compositional data analysis: a systematic scoping review with an interactive data exploration interface

BACKGROUND

How time is allocated influences health. However, any increase in time allocated to one behaviour must be offset by a decrease in others. Recently, studies have used compositional data analysis (CoDA) to estimate the associations with health when reallocating time between different behaviours. The aim of this scoping review was to provide an overview of studies that have used CoDA to model how reallocating time between different time-use components is associated with health.

METHODS

A systematic search of four electronic databases (MEDLINE, Embase, Scopus, SPORTDiscus) was conducted in October 2022. Studies were eligible if they used CoDA to examine the associations of time reallocations and health. Reallocations were considered between movement behaviours (sedentary behaviour (SB), light physical activity (LPA), moderate-to-vigorous physical activity (MVPA)) or various activities of daily living (screen time, work, household chores etc.). The review considered all populations, including clinical populations, as well as all health-related outcomes.

RESULTS

One hundred and three studies were included. Adiposity was the most commonly studied health outcome (n = 41). Most studies (n = 75) reported reallocations amongst daily sleep, SB, LPA and MVPA. While other studies reported reallocations amongst sub-compositions of these (work MVPA vs. leisure MVPA), activity types determined by recall (screen time, household chores, passive transport etc.) or bouted behaviours (short vs. long bouts of SB). In general, when considering cross-sectional results, reallocating time to MVPA from any behaviour(s) was favourably associated with health and reallocating time away from MVPA to any behaviour(s) was unfavourably associated with health. Some beneficial associations were seen when reallocating time from SB to both LPA and sleep; however, the strength of the association was much lower than for any reallocations involving MVPA. However, there were many null findings. Notably, most of the longitudinal studies found no associations between reallocations of time and health. Some evidence also suggested the context of behaviours was important, with reallocations of leisure time toward MVPA having a stronger favourable association for health than reallocating work time towards MVPA.

CONCLUSIONS

Evidence suggests that reallocating time towards MVPA from any behaviour(s) has the strongest favourable association with health, and reallocating time away from MVPA toward any behaviour(s) has the strongest unfavourable association with health. Future studies should use longitudinal and experimental study designs, and for a wider range of outcomes.

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.

Aerobic and Muscle-Strengthening Physical Activity, Television Viewing, and Nonalcoholic Fatty Liver Disease: The CARDIA Study

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) in U.S. adults is over 30%, yet the role of lifestyle factors in the etiology of NAFLD remains understudied. We examined the associations of physical activity, by intensity and type, and television viewing with prevalent NAFLD.

METHODS

Cross-sectional analysis of a population-based sample of 2726 Black (49%) and White (51%) adults (Mean (SD) age, 50 (3.6) years; 57.3% female) from the CARDIA study. Exposures were aerobic activity by intensity (moderate, vigorous; hours/week); activity type (aerobic, muscle-strengthening; hours/week); and television viewing (hours/week), examined concurrently in all models and assessed by validated questionnaires. Our outcome was NAFLD (liver attenuation < 51 Hounsfield Units), measured by non-contrast computed tomography, after exclusions for other causes of liver fat. Covariates were sex, age, race, study center, education, diet quality, smoking status, alcohol consumption, and body mass index or waist circumference.

RESULTS

648 participants had NAFLD. In the fully adjusted modified Poisson regression model, the risk ratios per interquartile range of each exposure were moderate-intensity aerobic activity, 1.10 (95% CI, 0.97-1.26); vigorous-intensity aerobic activity, 0.72 (0.63-0.82); muscle-strengthening activity, 0.89 (0.80-1.01); and television viewing, 1.20 (1.10-1.32). Relative to less active participants with higher levels of television viewing, those who participated in ≥2 h/week of both vigorous-intensity aerobic and muscle-strengthening activity and <7 h/week of television viewing had 65% lower risk of NAFLD (risk ratio = 0.35, 95% CI = 0.23-0.51).

CONCLUSION

Adults who follow public health recommendations for vigorous-aerobic and muscle-strengthening activity, as well as minimize television viewing, are considerably less likely to have NAFLD than those who do not follow the recommendations and who have relatively high levels of television viewing.

Current Treatment Options, Including Diet, Exercise, and Medications: The Impact on Histology

Paralleling the rise in obesity and diabetes, nonalcoholic fatty liver disease (NAFLD) is now the most prevalent chronic liver disease worldwide. Nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, may progress to cirrhosis, hepatic decompensation, and hepatocellular carcinoma. Despite its public health treat, no approved pharmacotherapies for NAFLD/NASH currently exist. Although the armamentarium of therapies for NASH is limited, current treatment options include life-style modification and the use of medications to treat metabolic comorbidities. This review addresses current approaches to the treatment of NAFLD/NASH, including the impact of diet, exercise, and available pharmacotherapies on the histologic features of liver injury.

Association of Accelerometer-Measured Sedentary Behavior Patterns With Nonalcoholic Fatty Liver Disease Among Older Adults: The MIND-China Study

INTRODUCTION

The relationships between sedentary behavior patterns and nonalcoholic fatty liver disease (NAFLD) in older adults are not well investigated.

METHODS

This population-based study included 1,899 rural-dwelling adults (aged 60 years or older). We assessed sedentary parameters with ActiGraph and defined NAFLD using ultrasonography.

RESULTS

Long total and prolonged sedentary time were associated with increased likelihoods of NAFLD, whereas engaging more breaks per sedentary hour and reallocating sedentary time to light-intensity physical activity were associated with reduced likelihoods of NAFLD (P linear <0.05).

DISCUSSION

Shorter sedentary time, engaging more frequent breaks in sedentary behavior, and replacing sedentary time with physical activity are associated with reduced likelihoods of NAFLD in older adults.

Novel Therapeutics in Nonalcoholic Fatty Liver Disease: A Focus on Adult Stem Cells

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder that is associated with abnormal accumulation of fat in the liver, which can lead to a wide variety of pathological liver defects and associated insulin resistance (IR), obesity, hypertension, dyslipidemia, diabetes, and cardiovascular disease. The molecular mechanisms that cause the initiation and progression of NAFLD are not fully understood. Increased lipolysis and de novo hepatic lipid synthesis lead to oxidative stress induced by reactive oxygen species and inflammation. Both these two entities could be interrelated and be an important mechanistic pathway, which can lead to tissue injury and hepatic cell death. Mechanisms for worsening of NAFLD include mitochondrial abnormalities, downregulation of glutathione (GSH), decreased activity of GSH-dependent antioxidants, accumulation of activated macrophages, hepatic inflammation, systemic inflammation, IR, and poorly controlled type 2 diabetes mellitus. Although no specific therapy has been approved for NAFLD, we review the latest medical therapeutics with emphasis on stem cell-based possibilities based on the presumed pathophysiology of NAFLD.

Association between intensity or accumulating pattern of physical activity and executive function in community-dwelling older adults: A cross-sectional study with compositional data analysis

Objective

Previous studies have suggested a positive association between physical activity (PA) and executive function in older adults. However, they did not adequately consider the compositional nature of daily time use and accumulated PA patterns. Therefore, this study aimed to examine the association between intensity or accumulated PA patterns and executive functions (inhibitory control, working memory, and cognitive flexibility) in community-dwelling older adults, considering the interaction of daily time spent in PA, sedentary behavior (SB), and sleep.

Method

This cross-sectional study used baseline data from a randomized controlled trial on the effect of exercise on cognitive function conducted between 2021 and 2022. Data from 76 community-dwelling older adults were used in the analysis. The time spent in PA and SB was assessed using an accelerometer, and sleep duration was self-reported. The Stroop task (inhibitory control), N-back task (working memory), and task-switching task (cognitive flexibility) were conducted to evaluate the subcomponents of executive function. Considering various potential confounders, compositional multiple linear regression analysis and compositional isotemporal substitution were performed to examine the association of PA with executive function and to estimate predicted changes in executive function in response to the hypothetical time-reallocation of movement behaviors, respectively.

Results

A longer time spent in light-intensity PA (LPA), relative to remaining behaviors, was associated with better Stroop task performance. Moreover, this association was stronger in LPA lasting longer than 10 min than in sporadic LPA. Additionally, theoretical 30 min/day time reallocation from SB or sleep to LPA was associated with better Stroop task performance (corresponding to approximately a 5%-10% increase). On the other hand, no significant associations of time spent in moderate- to vigorous-intensity PA with any subcomponents of executive function were observed.

Conclusion

LPA was positively associated with inhibitory control, and this association was stronger in bouts of LPA than in sporadic LPA. Moreover, reducing the time spent in SB or sleep and increasing the time spent in LPA, especially long-bout LPA, could be important measures for managing inhibitory control in late life. Future large longitudinal and intervention studies are needed to confirm these associations and reveal the causality and underlying mechanisms.

Association Between Physical Activity and Prevalence/Mortality of Non-Alcoholic Fatty Liver Disease in Different Socioeconomic Settings

Objectives: We aimed to investigate the effect of physical activity (PA) on non-alcoholic fatty liver disease (NAFLD) prevalence and long-term survival, particularly in some specific population such as those with different socioeconomic status (SES). Methods: Multivariate regression and interaction analyses were conducted to deal with confounders and interacting factors. Results: Active PA was associated with lower prevalence of NAFLD in both cohorts. Individuals with active-PA had better long-term survival compared to those with inactive-PA in both cohorts, and the results were only statistically significant in NAFLD defined by US fatty liver index (USFLI). We found clear evidence that the beneficial role of PA was more obvious in individuals with better SES, and the statistical significances were presented in both two hepatic steatosis index (HSI)-NAFLD cohorts from the NHANES III and NHANES 1999-2014. Results were consistent in all sensitivity analyses. Conclusion: We demonstrated the importance of PA in decrease the prevalence and mortality of NAFLD, and highlights the need for improving SES simultaneously to increase the protective effect of PA.

Isotemporal substitution of different behaviour patterns with the presence of MAFLD in Chinese adults

BACKGROUND

Lack of physical activity and excessive sitting time contributed to ectopic fat accumulation, especially in the liver. Previous studies have illustrated the harm of sedentary behaviour and the benefits of physical activity on fatty liver disease. We aimed to explore the association between the behaviour patterns and the risk of metabolic dysfunction-associated fatty liver disease (MAFLD) using isotemporal substitution model to examine the effect of replacing one behaviour to another while keeping the total time and other behaviours fixed among Chinese middle-aged and elderly population.

METHODS

This study included 161 147 participants aged ≥40 years old from the nationwide, population-based cohort of the REACTION study. The International Physical Activity Questionnaire was used to measure self-reported time for sleeping, sitting, walking and moderate-to-vigorous physical activity (MVPA). MAFLD was defined by evidence of fatty liver index (FLI) ≥ 60 in addition to one of the following three patterns, namely overweight/obesity, presence of diabetes, or evidence of metabolic dysregulation. Isotemporal substitution models using logistic regression models to evaluate the association of replacement of different behaviour patterns with each other and the risk of MAFLD.

RESULTS

Substitution of 60 minutes per day of sleeping, walking or total MVPA for sitting was associated with a 2%-8% reduction of MAFLD risk in overall participants. In employed individuals, replacing sitting time with occupational MVPA or nonoccupational MVPA both could bring benefits to liver steatosis. Stratified analysis found that replacing 60 minutes of sitting time with an equivalent time of other behaviour pattern could reduce approximately 8% of the risk among MAFLD participants with metabolic abnormalities. Such a relationship might be explained by the important mediated role of metabolic elements, such as waist circumference, body mass index, triglycerides and homoeostasis model assessment of insulin resistance. Furthermore, replacing sitting with MVPA showed a stronger association among participants who got enough sleep (sleep duration ≥7 hours per day).

CONCLUSION

Replacing sitting with other behaviour patterns could reduce the prevalence of MAFLD, and such substitution effect was much remarkably in individuals with abnormal metabolic status. Observably, obese individuals were more likely to benefit from appropriate changes in behaviour patterns. Moreover, the analysis of sleep duration stratification appealed that the adequacy of individual sleep duration also had a significant impact on the substitution effect. It is worth noting that adjusting the time allocation of behaviour patterns might have a beneficial impact on liver-metabolic health, and these findings might help us better recognize the importance of reasonable arrangement of behaviour patterns according to the individual's situation.

Association between Stages of Hepatic Steatosis and Physical Activity Performance in Adults with Metabolic Syndrome: A Cross-Sectional Analysis in FLIPAN Study

Background: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease. The best treatment now is a healthy lifestyle with a Mediterranean diet and physical activity (PA). Objective: To assess the association between stages of hepatic steatosis and physical activity performance in adults with metabolic syndrome. Design: Cross-sectional study in 155 participants (40–60 years old) with MetS, a diagnosis of NAFLD by magnetic resonance imaging and BMI (body mass index) between 27 and 40 kg/m². Methods: Stages of hepatic steatosis were assessed and defined according to the percentage of intrahepatic fat contents: stage 0 ≤ 6.4% (control group); stage 1 = 6.4–17.4%; stage 2 ≥ 17.4%. Fitness was assessed through ALPHA-FIT test battery for adults, aerobic capacity by Chester-step test and PA by accelerometry and Minnesota questionnaire. Results: Participants without NAFLD reported more years of education and major socioeconomic status than participants with NAFLD. A higher percentage of people in the most advanced stage of NAFLD were no smokers and no alcohol consumers. They also had higher stages of steatosis, lower sitting handgrip, standing handgrip, Chester step test values, sleep efficiency, and energy expenditure, and higher intensity of light and moderate physical activity, and self-reported physical activity. Conclusions: NAFLD patients showed lower fitness status, aerobic capacity, sleep efficiency and energy expenditure than non-NAFLD participants.