Racial differences in myocardial deformation in obese children: Significance of inflammatory state

Abstract

Background and aims: The association between racial differences in myocardial deformation and cardiometabolic risk factors is unknown in obese children. Our objective was to: 1) investigate for racial differences in myocardial deformation between white and black obese children and 2) identify biomarkers associated with these observed racial differences. We hypothesized that decreased myocardial deformation observed in black obese children could be accounted for by the differences in the markers of metabolic syndrome between the groups.

Methods and results: Obese children were recruited prospectively. All clinical and laboratory tests for the metabolic syndrome were conducted during a single assessment using a standardized protocol. Speckle-tracking echocardiography was performed to obtain longitudinal and circumferential measures of deformation. 310 patients were included in the analysis; 158 (51%) white and 152 (49%) black. The median age was 11.3 years (IQR 5.9). Blacks demonstrated worse longitudinal strain (-14.7 ± 2.7% vs. -15.4 ± 2.9%, p = 0.04). There was no difference in circumferential strain between the groups. Multivariable linear regression showed a significant relationship between longitudinal strain and hsCRP (β = 0.16, p = 0.03) and HOMA-IR (β = 0.15, p = 0.04); there was no independent association between longitudinal strain and race.

Conclusion: Black subjects demonstrated worse longitudinal strain than whites. Only hsCRP and HOMA-IR levels, not race, had an independent association with longitudinal strain, suggesting that the observed racial differences in longitudinal strain may be secondary to differences in inflammation and insulin resistance between the groups.

Keywords: Longitudinal strain; Metabolic syndrome; Obesity; Pediatrics; Race.

Figure 1:. Assessment of longitudinal strain

Speckle-tracking analysis to determine longitudinal strain (bottom strain curves) using Cardiac Performance Analysis v. 3.0 (Tomtec Imaging Systems, Unterschleissheim, Germany).