Excessive visceral fat was associated with incident cardiovascular disease and cancer after adjustment for clinical risk factors and general adiposity, results from a study of Framingham Heart Study participants showed.
The findings "support the growing appreciation of a pathogenic role of ectopic fat," researchers led by Dr. Kathryn A. Britton of the division of cardiovascular medicine at Brigham and Women’s Hospital, Boston, reported. The study was published online July 10 in the Journal of the American College of Cardiology. "Given the worldwide obesity epidemic, identification of high-risk individuals is important as it allows targeting of preventive and therapeutic measures. Furthermore, markers of risk may provide insight into the biology linking body fat distribution and outcomes."
Dr. Kathryn Britton
Since few studies have examined prospective outcomes in people with ectopic fat, the researchers set out to examine the association of directly-imaged fat measurements with incident CVD, cancer, and all-cause mortality in 3,086 participants from the Framingham Heart Study. All of the patients underwent multidetector computerized tomography with an 8-slice scanner in an effort to identify and measure areas of visceral adipose tissue, pericardial adipose tissue, and periaortic adipose tissue. During a median follow-up of 5 years, the study participants were assessed for heart disease, cancer, and death risk after adjustment for standard risk factors.
The mean age of the 3,086 patients was 50 years; 51% were men. At the end of the follow-up period, there were 90 cardiovascular events, 141 cancer cases, and 71 deaths. After multivariable adjustment using Cox proportional hazards regression models, the researchers found that each standard deviation increase in visceral adipose tissue was associated with cardiovascular disease (HR 1.44; P =.01) and cancer (HR 1.43; P = .005). None of the fat depots were associated with all-cause mortality.
"Numerous experimental studies support a potential link between visceral adipose tissue and biological pathways important in the pathogenesis of multiple disease outcomes," Dr. Britton and her colleagues wrote. "Adipokines, biologically active molecules secreted from adipose tissue, are key components of these pathways and include inflammatory cytokines, angiogenic factors, lipid metabolites, and extracellular matrix components. Adipokine secretion appears to differ between specific fat depots with visceral adipose tissue demonstrating greater expression of proinflammatory and proangiogenic genes, compared with subcutaneous adipose tissue."
The researchers acknowledged certain limitations of the study including the fact that the study sample was predominately white and that weight change data were not available on the participants during the follow-up period.
The study was supported by the National Heart, Lung and Blood Institute’s Framingham Heart Study. Dr. Britton was supported by a Research Career Development Award from the NHLBI.