Left Ventricular Function Across the Spectrum of Body Mass Index in African Americans: The Jackson Heart Study

Abstract

Objectives: This study sought to assess whether body mass index (BMI) was associated with subclinical left ventricular (LV) systolic dysfunction in African-American individuals.

Background: Higher BMI is a risk factor for cardiovascular disease, including heart failure. Obesity disproportionately affects African Americans; however, the association between higher BMI and LV function in African Americans is not well understood.

Methods: Peak systolic circumferential strain (ECC) was measured by tagged cardiac magnetic resonance in 1,652 adult African-American participants of the Jackson Heart Study between 2008 and 2012. We evaluated the association between BMI and ECC in multivariate linear regression and restricted cubic spline analyses adjusted for prevalent cardiovascular disease, conventional cardiovascular risk factors, LV mass, and ejection fraction. In exploratory analyses, we also examined whether inflammation, insulin resistance, or volume of visceral adipose tissue altered the association between BMI and ECC.

Results: The proportions of female, nonsmokers, diabetic, and hypertensive participants rose with increase in BMI. In multivariate-adjusted models, higher BMI was associated with worse ECC (β = 0.052; 95% confidence interval: 0.028 to 0.075), even in the setting of preserved LV ejection fraction. Higher BMI was also associated with worse ECC when accounting for markers of inflammation (C-reactive protein, E-selection, and P-selectin), insulin resistance, and volume of visceral adipose tissue.

Conclusions: Higher BMI is significantly associated with subclinical LV dysfunction in African Americans, even in the setting of preserved LV ejection fraction.

Keywords: BMI; Jackson Heart Study; LV function; cardiovascular disease; heart failure.

Figure 1. Forest plot of the associations between BMI and global circumferential systolic strain, overall and by subgroups

Forest plot of BMI beta coefficients by subgroups adjusting for covariates in regression model 3. 95% CI shown as solid horizontal line.

Figure 2. Adjusted Regression Analysis of BMI with Ecc and LV Ejection Fraction

(a) Adjusted cubic spline regression plot of global circumferential strain and BMI overlaid on a histogram illustrating the distribution of BMI among JHS participants. (b) Adjusted cubic spline regression plot of LVEF and BMI. Solid line depicts predicted values and dashed lines represent 95% CI.