Children and adolescents with low body mass index but large waist circumference remain high risk of elevated blood pressure

Abstract

BackgroundBody mass index (BMI) and waist circumference (WC) are two commonly used measurements for defining general and central obesity. The present study examined the profiles of blood pressure (BP) among children and adolescents with low BMI but large WC in a large population in Shandong, China. MethodsA total of 38,810 students (19,453 boys and 19,357 girls) aged 7–17years participated in this study. Height, weight, WC, and BP of all subjects were measured, and BMI was calculated. Relatively high BP (RHBP) status was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥95th percentile for age and gender. ‘Low BMI with large WC’ was defined as BMI<25th and WC≥75th. ResultsThe Z-scores for SBP and DBP in the ‘low BMI with large WC’ group were 0.21 and 0.31 for boys and 0.19 and 0.35 for girls respectively, significantly higher than the average level of the total sample (P<0.01). The prevalence of RHBP in the ‘low BMI with large WC’ group was significantly higher than the average level of the total sample (34.1% vs. 26.2% for boys and 29.5% vs. 20.3% for girls). ConclusionChildren and adolescents with low BMI but large WC might have an increased risk of elevated BP, their health risks would be underestimated if screening by BMI alone. These findings suggest that measurement of WC may be an assistive tool when using BMI to identify high BP risks.