[Weight status related early changes in blood pressure, cardiac structure and function in 4-year-old children]

Objective: To explore the association between weight status and early changes in blood pressure, cardiac structure and function in children at 4 years of age. Methods: A cross-sectional study of the relationship between weight status and cardiovascular parameters was performed on the platform of "Shanghai Birth Cohort" in Shanghai Xinhua Hospital between 2017 and 2020. Height, weight, blood pressure and echocardiography were measured in 1 477 children at 4 years of age. According to body mass index (BMI), participants were classified into five groups: underweight, lean, normal weight, overweight and obese. Blood pressure, cardiac structure and function indexes were compared among different groups using one-way ANOVA. The associations between blood pressure, cardiac structure and function and weight status in children were analyzed by linear regression models. Multivariate logistic regression models were used to analyze whether weight status was an independent risk factor for elevated blood pressure or left ventricular hypertrophy (LVH) in children. Results: A total of 1 477 children including 772 boys and 705 girls were included in this study. There were 115 overweight and obese boys (14.9%) and 68 overweight and obese girls (9.6%). The majority of children had normal weight (916 cases, 62.0%), followed by underweight (303 cases, 20.5%), overweight (130 cases, 8.8%), lean (75 cases, 5.1%), and obese (53 cases, 3.6%). With the increase of BMI, systolic blood pressure, diastolic blood pressure, left ventricular mass index (LVMI), left ventricular posterior wall thickness in systole, left ventricular posterior wall thickness in diastole, left ventricular diameter in end-systole, left ventricular diameter in end-diastole, interventricular septum thickness in systole and left ventricular ejection fraction showed significantly positive trend, and the differences among the groups were significant (F=31.73, 6.59, 14.22, 4.96, 3.01, 31.50, 39.79, 5.91, 3.09, all P<0.05). Multiple linear regression showed that overweight and obese were all positively associated with systolic blood pressure (β=5.2, 95%CI 3.6-6.8), LVMI (β=1.9, 95%CI 0.8-3.1), left ventricular diameter in end-systole (β=1.3, 95%CI 0.9-1.8), and left ventricular diameter in end-diastole (β=1.6, 95%CI 1.0-2.2). In the Logistic regression model, compared with normal weight children, overweight (OR=2.37, 95%CI 1.37-4.41) and obese children (OR=10.90, 95%CI 4.47-26.60) both had significantly increased risk of elevated blood pressure. However, the risk of LVH did not significantly increased. Conclusions: Overweight and obesity in 4-year-old children are associated with increased blood pressure, increased left ventricle diameter and LVMI. Overweight and obesity are independent risk factors for elevated blood pressure in children at 4 years of age.