Abstract
Background: Obesity is associated with structural and functional changes in the heart. Childhood underweight is also associated with an increased risk of later cardiovascular disease. In contrast to overweight/obesity, much less is known about underweight-related changes in left ventricular (LV) geometry and function. Myocardial performance index (MPI) combines both systolic and diastolic phases of cardiac cycle and has been shown to be useful for assessing global LV function. The purpose of the study is to assess the relationships between BMI z-score and LV geometry and MPI in children. Methods: Echocardiography with tissue Doppler imaging was performed in 643 children aged 7 to 15 years (BMI z-score -2.4 to +6.8). Subjects were divided into 9 groups according to BMI z-score. Cardiac dimensions, LV end-diastolic volume, LV mass, ejection fraction, isovolumic relaxation time (IRT), and tissue Doppler-derived MPI were measured. Results: There were significant relationships between BMI z-score and LV mass, LVEDV, and mass to volume ratio (r = 0.37, 0.23, and 0.39, p < 0.01, respectively). LVEF did not correlate with BMI z-score. A U-shaped association was observed between BMI z-score and MPI, and MPI at both BMI z-score <-2.0 and BMI z-score ≥ +3.0 were significantly greater compared with normal weight children as shown in Figure. There was a J-shaped association between BMI z-score and IRT with a significant increase at higher BMI (z-score ≥ +2.0). Conclusions: The present study suggests that lower BMI is associated with LV hypotrophy and increased MPI. Childhood underweight as well as overweight has a negative effect on cardiovascular function. Our findings suggest that primary prevention programs should be initiated in not only overweight but also underweight children.
Published Version
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