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Recent updates in nomenclature and diagnostic criteria encompass the diverse phenotypes associated with steatotic liver disease (SLD). 1 These updates aim to reflect the current understanding of SLD, promote disease awareness and research, and reduce stigma. Notably, the term metabolic dysfunction-associated steatotic liver disease (MASLD) is defined as hepatic steatosis with at least 1 of 5 cardiometabolic criteria without any other cause of steatosis. A new category, MetALD, includes those with MASLD and high alcohol intake. 1 We aimed to characterize SLD using this nomenclature in the Framingham Heart Study (FHS) and to quantify its association with cardiometabolic risk factors., (Copyright © 2024 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background: Arterial stiffening may contribute to the pathogenesis of metabolic dysfunction-associated steatotic liver disease. We aimed to assess relations of vascular hemodynamic measures with measures of hepatic steatosis and fibrosis in the community., Methods: Our sample was drawn from the Framingham Offspring, New Offspring Spouse, Third Generation, Omni-1, and Omni-2 cohorts (N=3875; mean age, 56 years; 54% women). We used vibration-controlled transient elastography to assess controlled attenuation parameter and liver stiffness measurements as measures of liver steatosis and liver fibrosis, respectively. We assessed noninvasive vascular hemodynamics using arterial tonometry. We assessed cross-sectional relations of vascular hemodynamic measures with continuous and dichotomous measures of hepatic steatosis and fibrosis using multivariable linear and logistic regression., Results: In multivariable models adjusting for cardiometabolic risk factors, higher carotid-femoral pulse wave velocity (estimated β per SD, 0.05 [95% CI, 0.01-0.09]; P =0.003), but not forward pressure wave amplitude and central pulse pressure, was associated with more liver steatosis (higher controlled attenuation parameter). Additionally, higher carotid-femoral pulse wave velocity (β=0.11 [95% CI, 0.07-0.15]; P <0.001), forward pressure wave amplitude (β=0.05 [95% CI, 0.01-0.09]; P =0.01), and central pulse pressure (β=0.05 [95% CI, 0.01-0.09]; P =0.01) were associated with more hepatic fibrosis (higher liver stiffness measurement). Associations were more prominent among men and among participants with obesity, diabetes, and metabolic syndrome (interaction P values, <0.001-0.04). Higher carotid-femoral pulse wave velocity, but not forward pressure wave amplitude and central pulse pressure, was associated with higher odds of hepatic steatosis (odds ratio, 1.16 [95% CI, 1.02-1.31]; P =0.02) and fibrosis (odds ratio, 1.40 [95% CI, 1.19-1.64]; P <0.001)., Conclusions: Elevated aortic stiffness and pressure pulsatility may contribute to hepatic steatosis and fibrosis., Competing Interests: Disclosures G.F. Mitchell is the owner of Cardiovascular Engineering, Inc, a company that designs and manufactures devices that measure vascular stiffness. The company uses these devices in clinical trials that evaluate the effects of diseases and interventions on vascular stiffness. G.F. Mitchell also serves as a consultant to and receives grants and honoraria from Novartis, Merck, Bayer, Servier, Philips, and deCODE genetics and is an inventor on a pending patent application that discloses a method for estimating carotid-femoral pulse wave velocity and vascular age by using a convolutional neural network. M.T. Long is a full-time employee of Novo Nordisk A/S; the data collection and primary analysis were completed while she was employed at Boston University. The other authors report no conflicts.

Background and Aims: The factors associated with incident hepatic steatosis are not definitively known. We sought to determine factors associated with incident hepatic steatosis, as measured on computed tomography, in the community., Methods: We studied Framingham Heart Study participants without heavy alcohol use or baseline hepatic steatosis who underwent computed tomography scans between 2002-2005 (baseline) and 2008-2011 (follow-up). We performed a stepwise logistic regression procedure to determine the predictors associated with incident hepatic steatosis., Results: We included 685 participants (mean age: 45.0 ± 6.2 years, 46.8% women). The incidence of hepatic steatosis in our sample was 17.1% over a mean 6.3 years of follow-up. Participants who developed hepatic steatosis had more adverse cardiometabolic profiles at baseline compared to those free of hepatic steatosis at follow-up. Multivariable stepwise regression analysis showed that a simple clinical model including age, sex, body mass index, alcohol consumption and triglycerides was predictive of incident hepatic steatosis (C statistic = 0.791, 95% CI: 0.748-0.834). A complex clinical model, which included visceral adipose tissue volume and liver phantom ratio added to the simple clinical model, and had improved discrimination for predicting incident hepatic steatosis (C statistic = 0.826, 95% CI: 0.786-0.866, P < .0001)., Conclusions: The combination of demographic, clinical and imaging characteristics at baseline was predictive of incident hepatic steatosis. The use of our predictive model may help identify those at increased risk for developing hepatic steatosis who may benefit from risk factor modification although further investigation is warranted., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

We examined associations between ambient air pollution and hepatic steatosis among 2,513 participants from the Framingham (Massachusetts) Offspring Study and Third Generation Cohort who underwent a computed tomography scan (2002-2005), after excluding men who reported >21 drinks/week and women who reported >14 drinks/week. We calculated each participant's residential-based distance to a major roadway and used a spatiotemporal model to estimate the annual mean concentrations of fine particulate matter. Liver attenuation was measured by computed tomography, and liver-to-phantom ratio (LPR) was calculated. Lower values of LPR represent more liver fat. We estimated differences in continuous LPR using linear regression models and prevalence ratios for presence of hepatic steatosis (LPR ≤ 0.33) using generalized linear models, adjusting for demographics, individual and area-level measures of socioeconomic position, and clinical and lifestyle factors. Participants who lived 58 m (25th percentile) from major roadways had lower LPR (β = -0.003, 95% confidence interval: -0.006, -0.001) and higher prevalence of hepatic steatosis (prevalence ratio = 1.16, 95% confidence interval: 1.05, 1.28) than those who lived 416 m (75th percentile) away. The 2003 annual average fine particulate matter concentration was not associated with liver-fat measurements. Our findings suggest that living closer to major roadways was associated with more liver fat., (© The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Aims: Nonalcoholic fatty liver (NAFL) is a common liver disease associated with metabolic syndrome, obesity, and diabetes that is rising in prevalence worldwide. Various molecular perturbations of key regulators and enzymes in hepatic lipid metabolism cause NAFL. However, redox regulation through glutathione (GSH) adducts in NAFL remains largely elusive. Glutaredoxin-1 (Glrx) is a small thioltransferase that removes protein GSH adducts without having direct antioxidant properties. The liver contains abundant Glrx but its metabolic function is unknown., Results: Here we report that normal diet-fed Glrx-deficient mice (Glrx -/- ) spontaneously develop obesity, hyperlipidemia, and hepatic steatosis by 8 months of age. Adenoviral Glrx repletion in the liver of Glrx -/- mice corrected lipid metabolism. Glrx -/- mice exhibited decreased sirtuin-1 (SirT1) activity that leads to hyperacetylation and activation of SREBP-1 and upregulation of key hepatic enzymes involved in lipid synthesis. We found that GSH adducts inhibited SirT1 activity in Glrx -/- mice. Hepatic expression of nonoxidizable cysteine mutant SirT1 corrected hepatic lipids in Glrx -/- mice. Wild-type mice fed high-fat diet develop metabolic syndrome, diabetes, and NAFL within several months. Glrx deficiency accelerated high-fat-induced NAFL and progression to steatohepatitis, manifested by hepatic damage and inflammation., Innovation: These data suggest an essential role of hepatic Glrx in regulating SirT1, which controls protein glutathione adducts in the pathogenesis of hepatic steatosis., Conclusion: We provide a novel redox-dependent mechanism for regulation of hepatic lipid metabolism, and propose that upregulation of hepatic Glrx may be a beneficial strategy for NAFL. Antioxid. Redox Signal. 27, 313-327.

Nonalcoholic fatty liver disease is associated with metabolic risk factors including hypertension and dyslipidemia and may progress to liver fibrosis. Studies have shown that hepatic steatosis and fibrosis are heritable, but whether they have a significant shared gene effect is unknown. This study examined the shared gene effects between hepatic steatosis and fibrosis and their associations with metabolic risk factors. This was a cross-sectional analysis of a prospective cohort of well-characterized, community-dwelling twins (45 monozygotic, 20 dizygotic twin pairs, 130 total subjects) from southern California. Hepatic steatosis was assessed with magnetic resonance imaging-proton density fat fraction and hepatic fibrosis with magnetic resonance elastography. A standard bivariate twin additive genetics and unique environment effects model was used to estimate the proportion of phenotypic variance between two phenotypes accounted for by additive genetic effects and individual-specific environmental effects. Genetic correlations estimated from this model represent the degree to which the genetic determinants of two phenotypes overlap. Mean (± standard deviation) age and body mass index were 47.1 (±21.9) years and 26.2 (±5.8) kg/m 2 , respectively. Among the cohort, 20% (26/130) had hepatic steatosis (magnetic resonance imaging-proton density fat fraction ≥5%), and 8.2% (10/122) had hepatic fibrosis (magnetic resonance elastography ≥3 kPa). Blood pressure (systolic and diastolic), triglycerides, glucose, homeostatic model assessment of insulin resistance, insulin, hemoglobin A1c, and low high-density lipoprotein had significant shared gene effects with hepatic steatosis. Triglycerides, glucose, homeostatic model assessment of insulin resistance, insulin, hemoglobin A1c, and low high-density lipoprotein had significant shared gene effects with hepatic fibrosis. Hepatic steatosis and fibrosis had a highly significant shared gene effect of 0.756 (95% confidence interval 0.716-1, P < 0.0001)., Conclusions: Genes involved with steatosis pathogenesis may also be involved with fibrosis pathogenesis. (Hepatology 2016;64:1547-1558)., Competing Interests: The authors report no conflict of interests., (© 2016 by the American Association for the Study of Liver Diseases.)

Background & Aims: Serum levels of aminotransferases are used as markers of nonalcoholic fatty liver disease in epidemiology research. However, it is not clear whether they can be used to identify patients with fatty liver. We investigated the accuracy of serum levels of aminotransferases in detection of hepatic steatosis. In addition, we derived a Framingham steatosis index (FSI) and tested its ability to identify patients with hepatic steatosis in an independent cohort., Methods: We performed a cross-sectional study of 1181 members of the Framingham Third Generation Cohort (46.1% women; mean age, 50.3 ± 6.7 years). People with hepatic steatosis were identified by computed tomography that was performed from 2008 through 2011. We compared the abilities of levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and the ratio of ALT:AST to identify people with hepatic steatosis by using c-statistic analyses. We performed a stepwise regression procedure to identify demographic and clinical factors that correlated with hepatic steatosis; we used these, along with biochemical factors associated with steatosis, to develop the FSI. We validated the FSI by using data from the third National Health and Nutrition Examination Survey., Results: The prevalence of hepatic steatosis in the Framingham Third Generation Cohort was 26.8%. The ratio of ALT:AST identified people with hepatic steatosis with the highest c-statistic value (0.728); the value for only ALT was 0.706, and the value for only AST was 0.589. We derived the FSI on the basis of patient age, sex, body mass index, levels of triglycerides, hypertension, diabetes, and ratio of ALT:AST. The FSI identified patients with hepatic steatosis with a c-statistic value of 0.845. When it was applied to the third National Health and Nutrition Examination Survey cohort, the FSI identified patients with steatosis with a c-statistic value of 0.760 and was well-calibrated., Conclusions: In an analysis of the Framingham Third Generation Cohort, we found the ratio of ALT:AST to identify people with hepatic steatosis more accurately than either ALT or AST alone. We used data from this cohort to develop and validate the FSI, which identifies patients with steatosis with a c-statistic value of about 0.8., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Objective: Prior studies on the association of physical activity (PA) and nonalcoholic fatty liver disease are limited by reliance on subjective measures of PA. We examined the association between objectively measured PA and hepatic steatosis defined by computed tomography (CT)., Methods: We conducted a cross-sectional study of 1,060 Framingham Heart Study participants who participated in the Multidetector CT 2 substudy and who underwent assessment of PA via accelerometry. Hepatic steatosis was estimated by liver attenuation, as measured by CT. We explored the relationship between liver attenuation and PA using multivariable regression models., Results: In multivariable-adjusted models, we observed an inverse association between PA and liver attenuation. Each 30 minutes/day increase in moderate to vigorous PA (MVPA) was associated with a reduced odds of hepatic steatosis (OR = 0.62, P < 0.001). This association was attenuated and no longer statistically significant after adjustment for body mass index (BMI) (OR = 0.77, P = 0.05) or visceral adipose tissue (VAT) (OR = 0.83, P = 0.18). Participants who met the national PA recommendations of engaging in ≥150 minutes/week of MVPA had the lowest odds of hepatic steatosis, even after adjusting for BMI (OR = 0.63, P = 0.007) or VAT (OR = 0.67, P = 0.03)., Conclusions: There is an inverse association between PA and hepatic steatosis. Participants who met the national PA guidelines had the lowest prevalence of hepatic steatosis., (© 2015 The Obesity Society.)