SAN FRANCISCO – A high volume of pericardial adipose tissue was associated with the prevalence of diabetes, independent of overall obesity, results from a long-term, diverse cohort study showed.
"Obesity is associated with an increased risk for cardiovascular disease and type 2 diabetes, and specific fat deposits may increase the risk more than others," Amy C. Alman, Ph.D., said at the annual scientific sessions of the American Diabetes Association.
The findings come from an analysis of year-25 exam data among 3,079 participants in CARDIA (Coronary Artery Risk Development in Young Adults), a longitudinal cohort study of the development of cardiovascular risk and disease that began in 1985 and was conducted at centers in Alabama, Minnesota, Illinois, and California.
Dr. Amy Alman
Visceral adiposity "is metabolically active and more strongly associated with cardiovascular risk than subcutaneous adiposity. Ectopic adipose depots are metabolically active fat found in and around tissues and organs throughout the body, including the liver, muscles, and around the heart," explained Dr. Alman of the department of epidemiology and biostatistics at the University of South Florida, Tampa.
Pericardial adipose tissue (PAT) is an ectopic fat depot composed of epicardial adipose tissue deep to the pericardium and surrounding the coronary arteries and paracardial tissue, which is located along the surface of the parietal pericardium. She and her associates tested whether PAT was positively associated with prevalent diabetes at the year-25 exam of the CARDIA study.
Examinations including volume of PAT measures from chest CT scans were performed during 2010-2011, and the researchers used multivariable logistic regression to examine the relation between quartiles of PAT and diabetes. There were four PAT quartiles: less than 33.5 cm3 (quartile 1/referent volume), between 33.5 and less than 48.7 cm3 (quartile 2), between 48.7 and less than 71.7 cm3 (quartile 3), and greater than 71.7 cm3 (quartile 4).
The mean age of the 3,079 study participants was 51 years, 44% were male, and their average body mass index was 31 kg/m2. Of these, 419 had prevalent diabetes. The prevalence of diabetes was highest in the fourth quartile of PAT volume (46% vs. 12% in the first quartile, 18% in the second, and 24% in the third), Dr. Alman reported.
In a logistic regression model of PAT volume on diabetes status by obesity, only PAT volume in the fourth quartile was significantly associated with diabetes status (odds ratio, 2.47), adjusted for field center, gender, age, race, systolic blood pressure, total cholesterol, triglycerides, and treatment with blood pressure– and cholesterol-lowering medications. A similar association was observed among nonobese patients (OR, 3.78).
"Deposition of a higher proportion of metabolically active ectopic fat is associated with diabetes in both obese and nonobese individuals," Dr. Alman concluded.
The analysis was "a very well characterized multicenter cohort study with a diverse racial cohort of middle-aged men and women," she added. Limitations of the study, she said, included its cross-sectional design, the fact that PAT was measured at a single point in time, and that it did not account for other ectopic fat depots such as liver fat. A longitudinal analysis of the participants is planned.
Dr. Alman had no relevant financial conflicts to disclose.