Sex differences in the relationship between adiposity and left ventricular morphology

Abstract

Background: Studies examining sex differences in the association between adiposity and left ventricular (LV) structure have been inconsistent. Many studies have used body-mass index (BMI), which combines influences from both lean mass and fat mass, potentially limiting its use for studying the relationship between adiposity and LV structure. Therefore, we aimed to delineate the relationship between lean mass and fat mass with LV mass and volume in both men and women using cardiovascular magnetic resonance (CMR). Methods: 221 adult volunteers (127 female, age range 18-72 years, mean 40.3 years) were recruited via advertisement. In order to study the effects of uncomplicated adiposity, volunteers were excluded if they gave a history of cardiovascular-related disease, including hypertension, hypercholesterolemia and diabetes. Lean mass and fat mass were measured using bioelectrical impedance analysis. LV structure was assessed via CMR, with LV mass, LV end-diastolic volume (LV EDV) and LV mass:volume ratio being calculated using CMRtools. The associations between the various measures of body composition and LV structure were assessed in multiple linear regression models, adjusted for age, blood pressure, gender and height. Results: Lean mass is the strongest predictor of LV mass (β=0.55, p 0.05). However, there were significant gender differences in the association between adiposity and LV mass and volume. Fat mass had a significant, positive association with LV mass for women (β=0.18, p=0.03) but not for men (β= -0.06, p=0.50). Similar results were seen for the association between LV EDV and fat mass (women: β=0.21, p=0.01; men: β= -0.07, p=0.40). In contrast, fat mass had no significant association with LV mass:volume ratio in either sex (women: β=0.07, p=0.47; men: β= -0.02, p=0.87). Conclusions: In a population without traditional cardiovascular risk factors, greater adiposity is associated with greater LV mass and LV dilatation (i.e. eccentric hypertrophy) in women but not in men. However, there was no relationship between adiposity and concentric hypertrophy (LV mass:volume ratio) in either sex. These findings may be due to biological factors specifically associated with female adiposity.