Different Associations of Systolic Blood Pressure and Body Mass Index With Cardiac Structure and Function in Young Children

Background: Both elevated systolic blood pressure (SBP) and excess weight can lead to early cardiovascular organ damage in children. In this study, we investigated whether there is a difference in the associations of SBP and body mass index (BMI) with cardiovascular structure and function in 4-year-old children. Methods: In 1474 children (52.3% males) from the Shanghai Birth Cohort, physical examination and echocardiography were performed. Standardized linear regression models were used to evaluate the associations of BMI Z score and SBP Z score with cardiovascular parameters and to compare the strengths of these associations. Results: The incidence of SBP elevation significantly increased in overweight children. SBP was positively related to heart rate, left ventricular (LV) ejection fraction and fraction shortening (beta=1.824 [95% CI, 1.014-2.634], 0.579 [0.294-0.864], and 0.480 [0.257-0.704], respectively). BMI Z score was positively associated with LV mass index (beta=1.225 [0.863-1.587]) and the risk of LV hypertrophy (odds ratio=1.428 [1.157-1.761]) but negatively related to measures of systolic function, including LV ejection fraction, LV fraction short, and global longitudinal strain (beta=-0.417 [-0.735 to -0.099], -0.302 [-0.551 to -0.053], and -0.392 [-0.621 to -0.163], respectively). No noteworthy additive or multiplicative interactions between BMI and SBP were detected. Conclusions: Elevations in both BMI and SBP were related to cardiac structure and function in children as young as 4 years old. Elevated SBP was associated with increased heart rate and LV ejection at the early stage of BP elevation. BMI showed a closer relationship with left heart diameters and geometry than SBP.