Epicardial adipose tissue and subclinical alterations in cardiac structure and function in early adulthood

Abstract Background Epicardial adipose tissue (EAT) is the visceral fat depot surrounding the heart and coronary arteries and shares the same microcirculation with myocardium. Under normal physiologic conditions EAT contains important cardioprotective properties such as cushioning the heart against mechanical stress, thermoregulation of the myocardium in hypothermia as well as balancing myocardial fatty acid homeostasis. Higher accumulation of EAT has been reported to independently associate with deleterious alterations in cardiac structure and function. However, majority of previously addressed study results are derived from older study population and in presence of cardiovascular diseases. Data on the associations of EAT and cardiac echocardiograpghically derived structural and functional parameters in a young and middle-aged population without prevalent cardiovascular disease is scarce. Purpose We aimed to address this knowledge gap by investigating the associations of echocardiographically measured EAT thickness and possible adverse subclinical alteration in cardiac structure and function in a population cohort of young and middle-aged adults. Methods This study participants were examined as part of the ongoing multi-centre longitudinal cohort, focusing on cardiovascular risk factors from childhood through adulthood. EAT thickness was measured by manual delineation from parasternal long-axis echocardiograms at end systole. Transthoracic and Doppler echocardiograpghy was performed and data on cardiac structural and functional parameters were derived comprehensively in accordance with EAE/ASE guidelines. Results In this study population (N=1677, men=770, women=897 ; age range 34-49 years) mean EAT thickness was 4.0 mm in whole population. In multivariable regression analysis models adjusted for age, sex, waist circumference and systolic blood pressure, significant independent associations of EAT and left atrial dimension (P<.0001) and various measures of left ventricular (LV) wall thickness such as LV mean wall thickness (P<.001), LV relative wall thickness (P<.001) as well as LV posterior wall thickness (P<.001) were observed. We found no significant associations between EAT thickness and cardiac functional and hemodynamic parameters after covariate adjustments in multivariable analysis models. Conclusion The findings of this study highlight that larger EAT thickness is associated with subclinical alteration in cardiac wall thicknesses in young and middle-aged adults. However, we found no associations between EAT thickness and cardiac functional parameters, which is perhaps due to the high cardiac adaptation properties in our relatively young study population. Therefore, further follow-ups is required to address long-term probable alterations in cardiac hemodynamics when the participants are older.