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.