Study Sample Characteristics by Tertiles of LA
Overall, 2882 participants (65% women) with an average age of 60 years were available for analysis. In the lowest LA tertile, cardiometabolic risk factor prevalence was generally higher, compared to the highest LA tertile (). Approximately, 55% were obese, 59% had metabolic syndrome and 27.8% had hepatic steatosis.
Clinical Characteristics (Mean ± SD) of Study Participants who underwent Computed Tomography Exam by Tertiles of Liver Attenuation (LA) (low liver attenuation=high liver fat)
Correlations with Liver Attenuation
Age-adjusted correlations of log LA with metabolic risk factors are displayed in . Log LA was inversely associated with all cardiometabolic risk factors tested including VAT, BMI, WC, triglycerides, fasting plasma glucose, hemoglobin A1C (HbA1C) and positively associated with HDL-C.
Age-Adjusted Pearson Correlation Coefficients between Log LA and Metabolic risk Factors
Multivariable-Adjusted Regression model with LA and Metabolic Risk Factors
The results of the multivariable-adjusted regressions for the association of log LA are summarized with continuous variables in and dichotomous metabolic risk factors in . We observed strong and consistent associations between log LA and most cardiometabolic outcomes. For example, lower log LA (per 1-SD decrement) was associated with higher fasting plasma glucose levels (3.79±0.7 mg/dl, p < 0.0001) after multivariable adjustment. The association persisted after additional adjustment for BMI (p=0.0001) and VAT (p=0.004). When comparing the association with cardiometabolic outcomes between VAT and log LA using bootstrap with 5000 replications, the regression coefficients were stronger for VAT with triglycerides (VAT: 0.18±0.1 vs. log LA: -0.12±0.0; p<0.0008 for difference) and HDL-C(VAT: -4.74±0.3 vs. log LA: 2.00±0.3; p<0.0001) than for log LA ().
A Multivariable-Adjusted# Regression coefficient of Continuous Variables for VAT and Log LA (per 1 SD Increment) with Cardiometabolic Risk Factors
A Multivariable-Adjusted# Odds Ratio of Dichotomous Variables for VAT and Log LA (per 1 SD Increment) with Cardiometabolic Risk Factors
For dichotomous variables, significant associations with log LA were also observed for impaired glucose, high triglycerides, low HDL-C, hypertension, diabetes, and the metabolic syndrome (). These associations persisted after additional adjustment for BMI or for VAT, with the exception of hypertension and impaired glucose. For differences in the regression coefficients between log LA and VAT with all risk factors examined, the magnitude of the associations was consistently stronger for VAT than for log LA with impaired glucose, high triglyceride, low HDL-C and metabolic syndrome (p-value range 0.009-0.0001) ( and ).
We also observed significant interactions between log LA and VAT for HDL-C (p = 0.009), impaired fasting glucose (p = 0.003) and metabolic syndrome (p = 0.04) ( and ), suggesting that participants with higher VAT and lower log LA had lower HDL-C levels, more impaired fasting glucose and metabolic syndrome compared to those with each condition alone.
Multivariable-Adjusted Association of Four Stratified Log LA / VAT Patterns and Cardiometabolic Risk Factors
We assessed the joint association of log LA and VAT with cardiometabolic risk factors. When the study sample was derived into four groups based on 25th percentile of log LA and 75th percentile of VAT in secondary analyses, significant differences were observed for all risk factors examined among 4 groups except for blood pressure and hypertension (all p<0.0001; ).
Multivariable-Adjusted# Means ± SD of Continuous Variables or Odds Ratio of Dichotomous Variables for Four VAT/LA Pattern
Among continuous variables, higher levels of fasting glucose, HbA1C, triglycerides, and lower levels of HDL-C were observed in the Low-LA/High-VAT group, the Low-LA/Low-VAT group and the High-LA/High-VAT group after adjustment for age, gender, smoking, alcohol consumption, BMI and medications for hypertension, diabetes and dyslipidemia as compared to the High-LA/Low-VAT group (p range 0.002 - 0.0001). Similar patterns were also observed for dichotomous variables. The risk factor prevalence was higher with greater levels of VAT (High-LA/High-VAT; p<0.0001), lower levels of log LA (Low-LA/Low-VAT; p range 0.001 - 0.0001) or both (Low-LA/High-VAT; p<0.0001) as compared to group with a reference group (High-LA/Low-VAT) ().
Figure 1 Prevalence of hypertension (HTN), diabetes (DM), impaired fasting glucose, high triglyceride, low HDL-C and Metabolic syndrome (MetS) among four group patterns (High-LA/Low-VAT, n=1704; Low-LA/Low-VAT, n=422; High-LA/High-VAT, n=436; Low-LA/High-VAT, (more ...)