Quantifying the relationships of blood pressure with weight, height and body mass index in Chinese children and adolescents

AIM: The aim of this study was to quantify the relationships of height, weight and body mass index (BMI) with blood pressure (BP) levels in Chinese children and adolescents. METHODS: Height, weight, BMI and BP measurements were obtained from a nationally representative sample of 231,227 children aged 7-18 years. Body size measurements were converted to age- and sex-specific standard deviation (SD) scores. The relationships between body size and BP measurements were assessed using linear regression analysis. RESULTS: All body size measurements were significantly associated with BP levels. Systolic BP increased 4.14, 3.70 and 2.88 mmHg in boys and 2.98, 2.63 and 1.87 mmHg in girls, corresponding to 1 SD increase in weight, BMI and height, respectively. A similar pattern was also observed for diastolic BP. After adjustment for height, systolic BP increased substantially with increasing weight (3.96 mmHg/SD increase for boys and 2.92 mmHg for girls). With adjustment for weight, systolic BP increased slightly with 1 SD increase in height (0.27 mmHg for boys and 0.10 mmHg for girls). The strength of the association between a body size measurement and BP varied among different ages, peaked at 10-11 years in girls and around 12-14 years in boys. CONCLUSIONS: Weight is the most powerful driving force of BP in children and adolescents, followed by BMI and height. Height has little impact on BP in children with a given weight, while weight has considerable impact on BP in children with a given height.