Increasing Liver Fat and Progression of CVD Risk Factors

In This Article

Abstract and Introduction
Methods
Results
Discussion
Conclusion
References
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Abstract and Introduction

Abstract

Background: Nonalcoholic fatty liver disease is associated with cardiovascular risk factors in cross-sectional analyses. However, less is known about how changes in liver fat associate with the progression of cardiovascular risk factors.

Methods: A substudy (n = 808) drawn from the Framingham Heart Study underwent serial computed tomography scans 6 years apart. We performed multivariable-adjusted regression to determine the association between changes in liver fat and progression of cardiovascular risk factors.

Results: Each standard deviation increase in liver fat was associated with adverse progression of systolic blood pressure, diastolic blood pressure, fasting glucose, high-density lipoprotein and log triglycerides. After adjusting for baseline cardiovascular risk, baseline body mass index (BMI), and change in BMI, increasing liver fat was significantly associated with adverse changes in fasting glucose and triglycerides.

Conclusions: In a longitudinal cohort, increasing liver fat over 6 years was associated with progression of cardiovascular risk factors, even after accounting for BMI changes.

Introduction

Nonalcoholic fatty liver disease (NAFLD) affects an estimated 25% of the globe's adult population^[1] and is the most common chronic liver disease in industrialized countries.^[2] Individuals with NAFLD are at increased risk for all-cause and cardiovascular disease (CVD)-related mortality.^[3] We have previously shown that liver fat assessed by computed tomography (CT) at baseline is associated with incident cardiovascular risk factors, including diabetes, hypertension and impaired fasting glucose (IFG).^[4] Liver fat is a dynamic process that can regress or progress, even independent of weight loss.^[5] However, few observational studies have investigated how changes in liver fat content over time are associated with the progression CVD risk factors, after accounting for covariates, including changes in body mass index (BMI).

The aim of this study was to examine the longitudinal associations between changes in liver fat with the progression of multiple CVD risk factors over time. We hypothesized that those with increasing liver fat would have adverse progression of CVD risk factors over the 6-year follow-up period.

Table 1. Baseline characteristics of the participants
Characteristics	Overall Participants (n = 808)
Characteristics	Baseline	Follow-up
Age, y	45.2 ± 6.3	51.3 ± 6.3
Women, n (%)	379 (46.9%)
Smoking, n (%)^a	80 (9.9%)	58 (7.2%)
Drinks per week	2.8 ± 3.3	3.0 ± 3.3
Weight (kg)	79.9 ± 17.1	82.2 ± 18.0
Body mass index, kg/m²	27.2 ± 5.1	28.2 ± 5.4
Waist circumference, cm	94.9 ± 14.1	98.3 ± 14.1
Liver phantom ratio	0.36 ± 0.05	0.35 ± 0.07
Systolic blood pressure, mmHg	118 ± 14	117 ± 13
Diastolic blood pressure, mmHg	76 ± 9	75 ± 8
Fasting glucose, mg/dL	97 ± 20	98 ± 19
HDL cholesterol, mg/dL	53 ± 16	58 ± 18
Triglycerides, mg/dL, median (25% to 75%)	97 (67–142)	96 (70–134)
NAFLD (liver phantom ratio ≤0.33)	112 (13.9%)	193 (23.8%)

Note: Data are represented as mean ± standard deviation or n, % unless otherwise noted.
Abbreviation: HDL, high-density lipoprotein.
^aDefined as smoking >1 cigarette per day over the past year.