ALEXANDRIA, VA – Data from a new study presented this week at The Liver Meeting Digital Experience® – held by the American Association for the Study of Liver Diseases – found that the distribution of a person’s body fat affects coronary heart disease risk, with an increased risk of heart events among people with a combination of high visceral adipose tissue (VAT) – abdominal fat─ and low liver fat. The study’s findings indicate that liver triglyceride regulation plays an important role in heart health in people with discordant visceral adipose tissue and liver fat levels.
Both elevated VAT and liver fat are common in people with metabolic disorders such as type 2 diabetes. While excess deep body fat is consistently linked to heart disease, liver fat’s association with cardiometabolic disorders is still unclear. To learn more, researchers in Europe conducted a new, large study to investigate coronary heart disease (CHD) risk related to VAT and liver fat levels and distribution. They used images from the UK Biobank, an international repository of biodata based in the United Kingdom.
“With the high prevalence of obesity and the rising prevalence of nonalcoholic fatty liver disease (NAFLD) in the population, we are facing an increasingly heterogeneous patient population. Recent studies have shown different fat deposits have variable impact on the development of cardiometabolic disease. Understanding patients’ individual way of storing fat can be valuable in developing targeted prevention and treatment strategies,” says the study’s co-author, Jennifer Linge, MSc, lead scientist, personalized medicine, at AMRA Medical AB in Linköping, Sweden.
First, the researchers used magnetic resonance images from 12,276 individuals scanned in the UK Biobank imaging study to measure VAT and liver proton density fat fraction (LF). Second, they divided participants into four phenotype groups defined by sex-specific average values of both visceral adipose tissue and liver fat: low VAT/low LF, low VAT/high LF, high VAT/low LF and high VAT/high LF.
Then, the researchers assessed associations of VAT/LF groupings with incident CHD using ICD-10 codes for ischemic heart disease or presence of aortocoronary bypass graft. They also performed an additional analysis to adjust for age and body-mass index (BMI). Participants were 51 percent female with a mean age of 62.6 years and a BMI of 26.6. They followed patients for a mean of 1.3 years. The researchers recorded 176 coronary heart disease events following imaging.
High VAT/low LF was the phenotype most strongly associated with incident CHD in the study, with this combination linked to significantly greater odds of developing CHD. High LF/low VAT was not associated with increased CHD risk. After adjusting for age and BMI, the association between high VAT/low LF and CHD was not as strong, but people with high VAT/low LF still had higher odds of developing CHD.
The study’s findings show that the distribution of body fat does affect CHD risk. The researchers also stress that the increased risk of heart-related events among those with high VAT and low LF indicates that liver triglyceride regulation plays an important role in cardiovascular health among people with visceral obesity.
“Our knowledge of patient risk for disease is limited when we restrict our assessment to single, isolated fat depots. These results indicate the importance of proper liver triglyceride regulation in the context of visceral adiposity,” says Ms. Linge. “When developing treatments for NAFLD, a decrease in liver fat alone may not be sufficient to lower of a patients’ cardiometabolic risk. In fact, it seems that a decrease in liver fat without a resolution of visceral obesity may put the patient at a greater risk of developing heart disease. This is what we want to investigate further.”
Jennifer Linge will present these findings at The Liver Meeting Digital Experience ™ during Parallel: NAFLD and NASH: Epidemiology and Outcomes on November 15 at 2 PM ET. The corresponding abstract “Can Low Liver Fat Be Bad for Your Heart? The High Visceral Fat, Low Liver Fat Phenotype: A Risk Factor for Coronary Heart Disease” can be found in the journal, HEPATOLOGY.
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