Prevalence of hypertension and prehypertension and its association with anthropometrics among children: a cross-sectional survey in Tianjin, China

To characterize the prevalence of hypertension and prehypertension and its association with four anthropometrics among children aged 7-15 years in Tianjin, China, a school-based cross-sectional survey was conducted from May to August 2010. Multistage random cluster sampling was used to select the participants. Body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and waist-to-hip ratio (WHR) were measured. Hypertension and prehypertension were identified according to the definition of United State Fourth Report. Logistic regression, linear regression and the area under receiver operating curves (AUC) was used for assessing the association. Among 1898 eligible children, the prevalence of hypertension and prehypertension was 6% and 6.6%, respectively. No statistically significant differences were found between boys and girls. Both linear and logistic regression showed that the four anthropometrics were all positively related to blood pressure value or the risk of prehypertension and hypertension. Of the four anthropometrics, BMI might be the most sensitive indicator for predicting elevated blood pressure, followed by WC and WHtR, whereas WHR had the lowest predicting capacity, with the AUCs being 0.72 (0.68,0.75), 0.69 (0.65,0.73), 0.67 (0.63,0.71), and 0.61 (0.57,0.65), respectively. A significantly increased prevalence of hypertension was observed when BMI > P90 percentiles, but for prehypertension, the risk of prehypertension began to increase when BMI was still at a median level. In conclusion, four anthropometrics all had positive relationship with elevated blood pressure. BMI and WC were superior to WHtR and WHR in predicting elevated blood pressure among children and adolescents.