Relation of regional fat distribution to left ventricular structure and function

Abstract

Background: The relation of body fat distribution to left ventricular (LV) structure and function is poorly defined.

Methods and results: A total of 2710 participants without heart failure or LV dysfunction in the Dallas Heart Study underwent dual energy x-ray absorptiometry and MRI assessment of fat distribution, LV morphology, and hemodynamics. Cross-sectional associations of fat distribution with LV structure and function were examined after adjustment for age, sex, race, comorbidities, and lean mass. Mean age was 44 years with 55% women; 48% blacks; and 44% obese. After multivariable adjustment, visceral adipose tissue was associated with concentric remodeling characterized by lower LV end-diastolic volume (β=-0.21), higher concentricity (β=0.20), and wall thickness (β=0.09; P<0.0001 for all). In contrast, lower body subcutaneous fat was associated with higher LV end-diastolic volume (β=0.48), reduced concentricity (β=-0.50), and wall thickness (β=-0.28, P<0.0001 for all). Visceral adipose tissue was also associated with lower cardiac output (β=-0.10, P<0.05) and higher systemic vascular resistance (β=0.08, P<0.05), whereas lower body subcutaneous fat associated with higher cardiac output (β=0.20, P<0.0001) and lower systemic vascular resistance (β=-0.18, P<0.0001). Abdominal subcutaneous fat showed weaker associations with concentric remodeling and was not associated with hemodynamics. Among the subset of obese participants, visceral adipose tissue, but not abdominal subcutaneous fat, was significantly associated with concentric remodeling.

Conclusions: Visceral adipose tissue, a marker of central adiposity, was independently associated with concentric LV remodeling and adverse hemodynamics. In contrast, lower body subcutaneous fat was associated with eccentric remodeling. The impact of body fat distribution on heart failure risk requires prospective study.

Keywords: body fat distribution; concentric remodeling; hypertrophy, left ventricular; intra-abdominal fat; obesity.

Figure 1. Concentricity index by visceral and lower body fat mass across BMI categories

Mean and SE of concentricity for visceral fat (A) and lower body fat (B) stratified by median level are shown by BMI category as follows: normal weight, BMI <25 kg/m² (n=642); overweight, 25≤BMI<30 kg/m² (n=875); obese BMI≥30 kg/m² (n=1133). Mean BMIs for fat mass ≤median and >median are 22 and 23, 27 and 27, and 35 and 36 kg/m² respectively for normal weight, overweight, and obese categories. *p<0.05 vs. ≤ median group.

Figure 2. Multivariable adjusted associations of visceral fat with the highest sex-specific quartile of concentricity index (>1.6 g/mL for women and >1.8 g/mL for men) by age, sex, race, and obesity subgroups

Odds ratios per 1-standard deviation increment in visceral fat mass. Adjusted for age, sex, African-American race, hypertension, diabetes, hyperlipidemia, exercise, alcohol use, cardiovascular disease, smoking, lean mass, abdominal subcutaneous fat, liver fat, and lower body fat mass. p-value for subgroup interaction.