Abstract MP13: Circulating Long-chain Monounsaturated Fatty Acids and Cardiac Structure and Function

Abstract

Background: We previously observed a prospective association of higher levels of plasma phospholipid long-chain monounsaturated fatty acids (LCMUFA, 22:1 and 24:1 fatty acids) with higher risk of incident congestive heart failure (CHF) in two independent cohorts: the Cardiovascular Health Study (CHS) and Atherosclerosis Risk in Communities Study. This is consistent with decades-old animal experiments demonstrating cardiotoxicity of LCMUFA, including cardiac lipid accumulation and dysfunction. However, relationships of LCMUFA to cardiac structure and function in humans are unknown. Aim: to evaluate associations of circulating LCMUFA with indices of cardiac structure and function including left-ventricular mass (LVM), LV hypertrophy (LVH), LV wall thickness, and systolic and diastolic function. Methods: We evaluated 2,220 CHS participants (age=74.6±5.0) in whom plasma phospholipid LCMUFA were measured in 1992 and M-mode echocardiography was performed in 1996. Primary outcomes were LVM index (LVM / height to the 2.7th power), LVH (LVM / height, >143 g/m for men and >102 g/m for women), LV wall thickness (average of posterior and septal wall thickness), systolic function (% fractional shortening), and diastolic function (ratio of early to atrial ventricular filling velocities, E/A ratio). Adjusting for sociodemographics, lifestyle factors, dietary factors, and prevalent cardiovascular diseases, we performed linear regression analyses to examine associations of 22:1 and 24:1 levels with each continuous outcome. For LVH (a common binary outcome), Poisson regression analysis was performed. Results: Mean±SD plasma phospholipid levels of 22:1 and 24:1 were 0.03±0.01 and 1.96±0.44 percent of total fatty acids. Across the interdecile range, higher levels of 22:1 and 24:1 were each associated with lower fractional shortening by 1.2% (95% confidence interval=0.1-2.3%, p=0.03) and 1.4% (0.2-2.7%, p=0.02), respectively. Higher levels of 22:1 and 24:1 were also associated with higher risk of LVH by 27% (0-62%, p=0.05) and 40% (5-86%, p=0.02), respectively. LCMUFA were not associated with LVM index, LV wall thickness, or E/A ratio (p>0.1 each). Findings were similar after excluding 410 adults with prevalent coronary heart disease or CHF. Conclusions: Higher circulating levels of plasma phospholipid 22:1 and 24:1 were associated with two indices of lower systolic function and greater risk of LVH, but not with other indices. These findings, if replicated, suggest mechanistic pathways whereby LCMFUA exposure may increase CHF risk and potentially inform future prevention efforts.