Comparison of body mass index with abdominal obesity for identifying elevated blood pressure in children and adolescents: The SNEC study

Body mass index (BMI) and waist circumference (WC) are two common ways to measure obesity. There is a debate, however, about which of these two measures are more closely associated with elevated blood pressure (BP). The aim of this study is to investigate the prevalence of obesity and whether BMI and WC is better associated with elevated BP in children and adolescents. A representative sample of 8613 Chinese youth aged 7–17 years from seven cities in Northeastern China was selected and measurements of height, weight, WC, BP were taken from 2012 to 2013. The average age of the children was 11.3 ± 2.3 years. The prevalence of overweight/obese and abdominal obesity in the subjects was 35% and 44.8%, respectively. We found that both BMI and WC were significantly associated with elevated BP. An increase of 1 kg m⁻² in BMI was associated with a 1.10 (1.08–1.12, 95% CI) increased risk of an elevated BP diagnosis in boys, and a 1.14 (1.11–1.16, 95% CI) increased risk in girls. Meanwhile, a 1 cm increase in WC correlated with a 1.03 (1.02–1.04, 95% CI) and a 1.05 (1.04–1.06, 95% CI) increased risk of higher BP in boys and girls, respectively. Compared to the normal-weight youth, subjects with elevated BMI (BMI > 85th) had higher risk of elevated BP (OR: 2.42, 95% CI: 2.13–2.75) than that of in elevated WC participants (OR: 2.00, 95% CI: 1.77–2.27). Therefore, BMI may associate better with elevated BP than WC in Chinese youth in our Seven Northeastern Cities study.