Association of a lifestyle index with MRI-determined liver fat content in a general population study

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.

The impact of sociodemographic status on the association of classical cardiovascular risk factors with coronary artery disease: a stratified Mendelian randomization study

OBJECTIVES

Low socioeconomic status (SES) is associated with cardiovascular risk factors and increased coronary artery disease (CAD) risk. We tested whether SES is an effect modifier of the association between classical cardiovascular risk factors and CAD using SES-stratified Mendelian Randomization in European-ancestry participants from UK Biobank.

STUDY DESIGN AND SETTING

We calculated weighted genetic risk scores (GRS) for the risk factors body mass index (BMI), systolic blood pressure, low-density lipoprotein cholesterol, and triglycerides. Participants were stratified by Townsend deprivation index score. Logistic regression models were used to investigate associations between GRSs and CAD occurrence. Additionally, stratification based on GRS-adjusted Townsend deprivation index residuals was conducted to correct for possible collider-stratification bias.

RESULTS

In a total sample size of N = 446,485, with 52,946 cases, the risk for CAD per standard deviation increase in genetically influenced BMI was highest in the group with the lowest 25% SES (odds ratio: 1.126, 95% confidence interval: 1.106-1.145; odds ratio: 1.081, 95% confidence interval: 1.059-1.103 in high SES), remaining similar after controlling for possible collider-stratification bias. The effects of genetically influenced systolic blood pressure, low-density lipoprotein cholesterol, and triglyceride on CAD were similar between SES groups.

CONCLUSION

CAD risk attributable to increased BMI is not homogenous and could be modified by SES. This emphasizes the need of tailor-made approaches for BMI-associated CAD risk reduction.

A healthy lifestyle during adolescence was inversely associated with fatty liver indices in early adulthood: findings from the DONALD cohort study

A healthy lifestyle during adolescence is associated with insulin sensitivity or liver enzyme levels and thus might contribute to the prevention of non-alcoholic fatty liver disease (NAFLD). Therefore, we examined the association between adherence to a hypothesis-based lifestyle score including dietary intake, physical activity, sedentary behaviour, sleep duration and BMI in adolescence and fatty liver indices in early adulthood. Overall, 240 participants of the DOrtmund Nutritional and Anthropometric Longitudinally Designed study completed repeated measurements of lifestyle score factors during adolescence (females: 8·5-15·5 years, males: 9·5-16·5 years). Multivariable linear regression models were used to investigate the association between adolescent lifestyle scores and NAFLD risk (hepatic steatosis index (HSI) and fatty liver index (FLI)) in early adulthood (18-30 years). Participants visited the study centre 4·9 times during adolescence and achieved on average 2·8 (min: 0·6, max: 5) out of five lifestyle score points. Inverse associations were observed between the lifestyle score and fatty liver indices (HSI: ß=-5·8 % (95 % CI -8·3, -3·1), P < 0·0001, FLI: ß=-32·4 % (95 % CI -42·9, -20·0), P < 0·0001) in the overall study population. Sex-stratified analysis confirmed these results in men, while inverse but non-significant associations were observed in women (P > 0·05). A higher lifestyle score was associated with lower HSI and FLI values, suggesting that a healthy lifestyle during adolescence might contribute to NAFLD prevention, predominantly in men. Our findings on repeatedly measured lifestyle scores in adolescents and their association with NAFLD risk in early adulthood warrant confirmation in larger study populations.

Higher Adherence to Healthy Lifestyle Score Is Associated with Lower Odds of Non-Alcoholic Fatty Liver Disease

Growing evidence supports that individual lifestyle factors contribute to the development of non-alcoholic fatty liver disease (NAFLD) without considering the coexistence and synergistic effect of lifestyle factors. Our aim is to derive a healthy lifestyle score (HLS) and estimate its association with NAFLD. In this nationwide cross-sectional study, we derived a five-item HLS including dietary pattern, body mass index, physical activity, cigarette smoking, and sleep duration. NAFLD and clinically significant fibrosis (CSF) were assessed based on vibration-controlled transient elastography (VCTE). Liver function parameters were also tested. Multivariable logistic and linear regressions were applied to investigate the association between HLS and liver diseases. Of the 3893 participants with VCTE examination, approximately 14.1% of participants possessed zero or one healthy lifestyle, 62.5% possessed two or three healthy lifestyles, and 23.4% possessed four or five healthy lifestyles. Compared with participants with a low HLS (0−1 score), the adjusted odds ratios and 95% confidence intervals for those with a high HLS (4−5 score) were 0.25 (0.19~0.33, Ptrend < 0.001) for NAFLD and 0.30 (0.18~0.50, Ptrend < 0.001) for CSF. HLS was positively associated with albumin, total protein, and total bilirubin (all Ptrend ≤ 0.001), and was inversely associated with globulin, alanine aminotransferase, and gamma-glutamyl transaminase (all Ptrend ≤ 0.003). Higher adherence to HLS is associated with lower odds of NAFLD and CSF and may improve liver function. Strategies for the promotion of a healthy lifestyle should be considered as part of NAFLD prevention.

Nonalcoholic fatty liver disease: lifestyle and quality of life

Nonalcoholic fatty liver disease (NAFLD) is a metabolic disorder whose current rapidly expanding prevalence is causing it to develop into a major global health concern. NAFLD is closely linked to the modern, unhealthy lifestyle. The Western diet, characterized by excessive energy intake, frequent consumption of red meat, processed meat and foods, soft drinks, and sugar-sweetened beverages (SSBs), irregular meal distribution throughout the day, and unhealthy ways of cooking, predisposes to development of NAFLD. Low levels of physical activity and prolonged sedentary time are additional lifestyle risk factors for NAFLD. Given the present lack of effective pharmacological treatment, lifestyle modifications are regarded as the cornerstone of NAFLD management. Reducing daily calorie intake together with following the Mediterranean diet (MD) is an increasingly accepted approach. Furthermore, increasing the level of physical activity and limiting sedentary behavior are additional measures proposed to improve the outcomes of the disease. Apart from being affected by lifestyle, NAFLD may also affect patients' quality of life (QoL), mostly in the domain of physical function. In this regard, while the early and more benign form of the disease, i.e., simple hepatic steatosis, may not affect QoL, there is evidence, though conflicting, of the impact of nonalcoholic steatohepatitis (NASH) on this index, with, however, most studies showing that QoL is consistently affected in advanced disease, i.e., hepatic fibrosis, cirrhosis, and hepatocellular carcinoma. Considering all the above, appropriate management of lifestyle is likely to attenuate the severity of the disease and improve the QoL of NAFLD patients.

Higher Healthy Lifestyle Score is associated with lower presence of non-alcoholic fatty liver disease in middle-aged and older Chinese adults: a community-based cross-sectional study

OBJECTIVE

Previous studies have reported inverse associations between certain healthy lifestyle factors and non-alcoholic fatty liver disease (NAFLD), but limited evidence showed the synergistic effect of those lifestyles. This study examined the relationship of a combination of lifestyles, expressed as Healthy Lifestyle Score (HLS), with NAFLD.

DESIGN

A community-based cross-sectional study. Questionnaires and body assessments were used to collect data on the six-item HLS (ranging from 0 to 6, where higher scores indicate better health). The HLS consists of non-smoking (no active or passive smoking), normal BMI (18·5-23·9 kg/m2), physical activity (moderate or vigorous physical activity ≥ 150 min/week), healthy diet pattern, good sleep (no insomnia or <6 months) and no anxiety (Self-rating Anxiety Scale < 50), one point each. NAFLD was diagnosed by ultrasonography.

SETTING

Guangzhou, China.

PARTICIPANTS

Two thousand nine hundred and eighty-one participants aged 40-75 years.

RESULTS

The overall prevalence of NAFLD was 50·8 %. After adjusting for potential covariates, HLS was associated with lower presence of NAFLD. The OR of NAFLD for subjects with higher HLS (3, 4, 5-6 v. 0-1 points) were 0·68 (95 % CI 0·51, 0·91), 0·58 (95 % CI 0·43, 0·78) and 0·35 (95 % CI 0·25, 0·51), respectively (P-values < 0·05). Among the six items, BMI and physical activity were the strongest contributors. Sensitivity analyses showed that the association was more significant after weighting the HLS. The beneficial association remained after excluding any one of the six components or replacing BMI with waist circumference.

CONCLUSIONS

Higher HLS was associated with lower presence of NAFLD, suggesting that a healthy lifestyle pattern might be beneficial to liver health.

Higher healthy lifestyle scores are associated with greater bone mineral density in middle-aged and elderly Chinese adults

This study examined the association between healthy lifestyle score (HLS), which contained 7 items (smoking, BMI, physical activity, diet, alcohol, sleep and anxiety) and BMD. Results showed HLS was positively associated with BMD at all studied sites, suggesting that healthier lifestyle patterns might be beneficial to bone health.

PURPOSE

Previous studies have reported favourable associations of individual healthy lifestyle factors with bone mineral density (BMD), but limited evidence showed the relationship of a combined healthy lifestyle score (HLS) with BMD. This study examined the association between the HLS and BMD.

METHODS

This community-based cross-sectional study included 3051 participants aged 40-75 years. The HLS contained 7 items (smoking, BMI, physical activity, diet quality, alcohol intake, sleep and anxiety). BMD values of whole body (WB), lumbar spine 1-4 (L_1-4), total hip (TH) and femur neck (FN) were measured using dual-energy X-ray absorptiometry.

RESULTS

After adjusting for potential covariates, HLS was positively associated with BMD at all studied sites (P-trend < 0.01). The mean BMDs were 2.69% (WB), 5.62% (L_1-4), 6.13% (TH) and 5.71% (FN) higher in participants with HLS of 6-7 points than in those with HLS of 0-2 points. The per 1 of 7 unit increase in the HLS was associated with increases of 7.63 (WB)-13.4 (TH) mg/cm² BMD levels at all sites. These favourable associations tended to be more pronounced in men than in women. Among the 7 items, physical activity contributed most to the favourable associations, followed by BMI, non-smoking and diet; the other three items played little roles. Sensitivity analyses showed that the significant associations remained after excluding any one of the 7 components or excluding fracture subjects at all sites.

CONCLUSION

Higher HLS was associated with greater BMD in middle-aged and elderly Chinese, suggesting that healthier lifestyle patterns might be beneficial to bone health.

The association between adherence to the Mediterranean diet and hepatic steatosis: cross-sectional analysis of two independent studies, the UK Fenland Study and the Swiss CoLaus Study

BACKGROUND AND AIMS

The risk of hepatic steatosis may be reduced through changes to dietary intakes, but evidence is sparse, especially for dietary patterns including the Mediterranean diet. We investigated the association between adherence to the Mediterranean diet and prevalence of hepatic steatosis.

METHODS

Cross-sectional analysis of data from two population-based adult cohorts: the Fenland Study (England, n = 9645, 2005-2015) and CoLaus Study (Switzerland, n = 3957, 2009-2013). Habitual diet was assessed using cohort-specific food frequency questionnaires. Mediterranean diet scores (MDSs) were calculated in three ways based on adherence to the Mediterranean dietary pyramid, dietary cut-points derived from a published review, and cohort-specific tertiles of dietary consumption. Hepatic steatosis was assessed by abdominal ultrasound and fatty liver index (FLI) in Fenland and by FLI and non-alcoholic fatty liver disease (NAFLD) score in CoLaus. FLI includes body mass index (BMI), waist circumference, gamma-glutamyl transferase, and triglyceride; NAFLD includes diabetes, fasting insulin level, fasting aspartate-aminotransferase (AST), and AST/alanine transaminase ratio. Associations were assessed using Poisson regression.

RESULTS

In Fenland, the prevalence of hepatic steatosis was 23.9% and 27.1% based on ultrasound and FLI, respectively, and in CoLaus, 25.3% and 25.7% based on FLI and NAFLD score, respectively. In Fenland, higher adherence to pyramid-based MDS was associated with lower prevalence of hepatic steatosis assessed by ultrasound (prevalence ratio (95% confidence interval), 0.86 (0.81, 0.90) per one standard deviation of MDS). This association was attenuated [0.95 (0.90, 1.00)] after adjustment for body mass index (BMI). Associations of similar magnitude were found for hepatic steatosis assessed by FLI in Fenland [0.82 (0.78, 0.86)] and in CoLaus [0.85 (0.80, 0.91)], and these were also attenuated after adjustment for BMI. Findings were similar when the other two MDS definitions were used.

CONCLUSIONS

Greater adherence to the Mediterranean diet was associated with lower prevalence of hepatic steatosis, largely explained by adiposity. These findings suggest that an intervention promoting a Mediterranean diet may reduce the risk of hepatic steatosis.

Smoking results in accumulation of ectopic fat in the liver

OBJECTIVE

An association between smoking and nonalcoholic fatty liver disease has been reported. However, objective quantification of intrahepatic fat via magnetic resonance spectroscopy (MRS) in relation to smoking has rarely been performed in previous studies. Moreover, the possible pathways via which smoking could induce ectopic fat accumulation have not yet been addressed. The current study aimed to examine the association between smoking status and intrahepatic fat quantity and explore the possible mediating effects of triglycerides (TG) and adiponectin.

SUBJECTS AND METHODS

Magnetic resonance imager (MRI) spectra were analyzed to quantify intrahepatic fat in 45 men who were on average 62.3 years of age. Smoking status and alcohol intake were self-reported. Accelerometers were used to record daily total physical activity. Fasting blood TG and adiponectin levels were measured enzymatically. Differences in mean intrahepatic fat values according to smoking status were assessed using analysis of covariance.

RESULTS

A stepwise increase in mean intrahepatic fat was observed between never, former, and current smokers, respectively, independent of age, physical activity, alcohol intake, and body mass index (BMI) (P=0.005). Adjustment for TG and adiponectin significantly attenuated this association (P=0.074).

CONCLUSION

Current smoking was significantly associated with increased intrahepatic fat, which may be a result of adipocyte dysfunction, manifested as high circulating TG concentrations and low adiponectin levels.

Metabolic Inflexibility Is an Early Marker of Bed-Rest-Induced Glucose Intolerance Even When Fat Mass Is Stable

Context

The effects of energy-balanced bed rest on metabolic flexibility have not been thoroughly examined.

Objective

We investigated the effects of 21 days of bed rest, with and without whey protein supplementation, on metabolic flexibility while maintaining energy balance. We hypothesized that protein supplementation mitigates metabolic inflexibility by preventing muscle atrophy.

Design and Setting

Randomized crossover longitudinal study conducted at the German Aerospace Center, Cologne, Germany.

Participants and Interventions

Ten healthy men were randomly assigned to dietary countermeasure or isocaloric control diet during a 21-day bed rest.

Outcome Measures

Before and at the end of the bed rest, metabolic flexibility was assessed during a meal test. Secondary outcomes were glucose tolerance by oral glucose tolerance test, body composition by dual energy X-ray absorptiometry, ectopic fat storage by magnetic resonance imaging, and inflammation and oxidative stress markers.

Results

Bed rest decreased the ability to switch from fat to carbohydrate oxidation when transitioning from fasted to fed states (i.e., metabolic inflexibility), antioxidant capacity, fat-free mass (FFM), and muscle insulin sensitivity along with greater fat deposition in muscle (P < 0.05 for all). Changes in fasting insulin and inflammation were not observed. However, glucose tolerance was reduced during acute overfeeding. Protein supplementation did not prevent FFM loss and metabolic alterations.

Conclusions

Physical inactivity triggers metabolic inflexibility, even when energy balance is maintained. Although reduced insulin sensitivity and increased fat deposition were observed at the muscle level, systemic glucose intolerance was detected only in response to a moderately high-fat meal. This finding supports the role of physical inactivity in metabolic inflexibility and suggests that metabolic inflexibility precedes systemic glucose intolerance.

Association between smoking and non-alcoholic fatty liver disease: A systematic review and meta-analysis

Background/aims

Non-alcoholic fatty liver disease is one of the most common chronic liver diseases. Some risk factors are known to influence the development of non-alcoholic fatty liver disease, but the effect of tobacco smoking on the progression of non-alcoholic fatty liver disease is controversial. The main goal of this systematic review and meta-analysis is to investigate the association between smoking and non-alcoholic fatty liver disease.

Method

Electronic databases (PubMed, Scopus, and ISI Web of Science) were searched to find published articles on non-alcoholic fatty liver disease and smoking until December 2016. All relevant studies were screened by inclusion and exclusion criteria and compatible studies were chosen. The Newcastle-Ottawa Scale was used to assess the methodological quality of eligible articles. Subsequently, information was gathered based on the following: author, publication year, keywords, country, inclusion and exclusion criteria, main results, study design, conclusion, and confounder variables (age, body mass index, gender, ethnicity, and diabetes). Finally, analyses were performed using Comprehensive Meta-Analysis Software.

Results

Data were extracted from 20 observational studies (9 cross-sectional, 6 case-control, 4 cohort studies, and 1 retrospective cohort study). A significant association was observed between smoking and non-alcoholic fatty liver disease with a pooled odds ratio of 1.110 (95% confidence interval, 1.028-1.199), p-value = 0.008. The statistical heterogeneity was medium with an I2 of 40.012%, p-heterogeneity = 0.074. Also there was a significant relation between non-alcoholic fatty liver disease and passive smoking with a pooled odds ratio of 1.380 (95% confidence interval, 1.199-1.588; p-value = 0.001; I2 = 59.41; p-heterogeneity = 0.117).

Conclusion

Our meta-analysis demonstrated that smoking is significantly associated with non-alcoholic fatty liver disease. Further prospective studies exploring the underlying mechanisms of this association should be pursued. Also passive smoking increases the risk of non-alcoholic fatty liver disease about 1.38-fold. The effects of smoking cigarettes on active smokers (current smoker, former smoker, and total smoker) are less than passive smokers. Further studies are needed to compare the of effects of passive and active smoking on non-alcoholic fatty liver disease.

Association between MRI-derived hepatic fat fraction and blood pressure in participants without history of cardiovascular disease

OBJECTIVES

We assessed whether liver fat content, as determined by MRI, correlates with blood pressure (BP), a major vascular risk factor, in individuals from the general population without history of stroke and coronary or peripheral artery disease.

METHODS

Cross-sectional data from 384 participants (161 women; aged 39-73 years) of a MRI substudy of the KORA FF4 survey were used. Hepatic fat fraction (HFF) was measured in the left and right lobe of the liver using single voxel multiecho H-spectroscopy and at the level of the portal vein using a multiecho Dixon-sequence. Associations of HFF with SBP and DBP as well as hypertension were assessed by right censored normal regression (accounting for antihypertensive treatment) and by logistic regression, respectively.

RESULTS

High levels of HFF measured on the level of the portal vein (90th percentile, 21.8%), compared with low HFF levels (10th percentile, 1.7%), were associated with higher SBP (131 vs. 122 mmHg; overall P = 0.001), higher DBP (82 vs. 76 mmHg, P < 0.001) and with higher odds of hypertension [odds ratio (OR) = 2.16, P = 0.025]. A level of 5.13% (54th percentile) was identified as optimal HFF cut-off for the prediction of hypertension (OR = 2.00, P = 0.015). Alcohol consumption emerged as an effect modifier for the association between HFF and hypertension (nonalcohol drinker: OR = 3.76, P = 0.025; alcohol drinker: OR = 1.59, P = 0.165).

CONCLUSION

MRI-derived subclinical HFF is associated with SBP and DBP as well as with hypertension in participants from the general population without history of cardiovascular disease.