Association between chest CT-derived body composition measurements at the sternal angle level and epicardial fat volume: a retrospective cross-sectional study

Background Epicardial fat volume (EFV) is a recognized imaging biomarker linked to cardiometabolic risk. Its assessment on routine chest CT offers an opportunity to extract additional clinical information. This study aimed to investigate the associations of EFV with chest CT-derived body composition parameters at the sternal angle level, including subcutaneous fat area and pectoralis major (PM) muscle characteristics, as well as with age and sex. Results This retrospective cross-sectional study included 110 patients who underwent non-ECG- gated chest CT. EFV was quantified, and body composition parameters, including subcutaneous fat area and total PM muscle area and mean attenuation, were measured at the sternal angle level. Associations were evaluated using univariable analysis and multivariable linear regression adjusting for potential confounders. No significant difference in EFV was observed between males and females on univariable analysis; however, sex was independently associated with EFV after adjustment (B = 15.17, 95% − CI − 28.13– − 2.22; p = 0.022(. Age was independently associated with EFV, with a progressive increase observed with advancing age (B = 1.26, 95% CI 0.88–1.65, p < 0.001). In univariable analyses, associations between EFV and chest subcutaneous fat area were assessed separately in males and females because of anatomical differences in regional fat distribution. Subcutaneous fat area was positively correlated with EFV in both males (rs = 0.37, p = 0.005) and females (rs = 0.31, p = 0.025). In the multivariable linear regression model, sex was included as a covariate to account for sex-related differences, and subcutaneous fat area remained independently associated with EFV (B = 0.03, 95% CI 0.01–0.06; p = 0.002). Although PM muscle attenuation showed a significant inverse association with EFV on univariable analysis (rs = − 0.20, p = 0.031), this association was not maintained after adjustment (B = − 0.02, 95% CI − 0.65–0.6, P = 0.948). PM muscle area was not independently associated with EFV (B = 0.07, 95% CI − 0.12–0.23, P = 0.381). Conclusion EFV is independently associated with age, sex, and local chest subcutaneous fat area. Pectoralis muscle parameters were not independently associated with EFV.