Abstract 15683: The Effect of Body Composition on the Association Between Adiposity-Associated Inflammation and Coronary Artery and Abdominal Aortic Calcium: The Multi-Ethnic Study of Atherosclerosis (MESA)

Abstract

Background: Secreted by adipose tissue, adipokines regulate glucose and fatty acid metabolism and participate in inflammatory processes linked to coronary artery and abdominal aorta calcification (CAC and AAC). Because adipokine secretion differs by adipose tissue type, we hypothesized that body composition modifies associations between these adiposity-associated inflammatory markers (AAIMs) and CAC and AAC.

Methods: We evaluated 1878 MESA participants with complete measures of AAIMs, anthropometry, CAC, and AAC. Associations of AAIMs with CAC and AAC prevalence and severity were analyzed per standard deviation (SD) using staged log binomial and linear regression models. Waist-hip ratio (WHR) was dichotomized into categories based on median WHR values for sex and ethnicity. Calcium prevalence was defined as any calcium (Agatston > 0), while severity was defined as natural log Agatston score. Analyses were adjusted for demographics and traditional CVD risk factors. Interactions of WHR with AAIMs were examined on a multiplicative or additive scale as appropriate.

Results: Each SD greater IL-6 and fibrinogen corresponded to 5% greater CAC prevalence (95% CI: 1.02-1.07; 1.02-1.08) and 4% greater AAC prevalence (95% CI: 1.02-1.05; 1.01-1.06). CRP corresponded to 5% greater CAC prevalence (95% CI: 1.02-1.08). IL-6 and fibrinogen were associated with 14.1% and 13.5% higher AAC severity, respectively (p=0.003; p=0.010). Adiponectin, leptin, resistin, and TNFa were not associated with CAC or AAC prevalence or severity. Associations of IL-6 and fibrinogen with CAC severity were modified by WHR; each SD greater IL-6 was associated with 21.3% greater CAC severity among higher WHR (p=0.007), whereas no association was observed among lower WHR (Interaction p = 0.014). Similarly, each SD greater fibrinogen was associated with 19.2% greater CAC severity among higher WHR (p=0.019), whereas no association was observed among lower WHR (Interaction p = 0.034).

Conclusion: Higher concentrations of IL-6 and fibrinogen were significantly associated with prevalence and severity of CAC and AAC; and CRP only with CAC. However, the association of IL-6 and fibrinogen with CAC severity was modified by WHR, such that associations were stronger in those with higher WHR.