Role of waist circumference in predicting the risk of high blood pressure in children

Objective. This paper was designed to evaluate the role of waist circumference (WC) in identification of children with high blood pressure. Methods. Cross-sectional data on body mass index (BMI), WC and blood pressure (BP) were analyzed in 3 678 children (1 849 boys; 11.3 +/- 2.3 years) who participated in the LEARN study. Results. Prevalence of abdominal obesity (WC >= 90th percentile) in normal weight (n = 2 982), overweight (n = 528) and obese (n = 168) children were 3.7%, 51.7% and 89.9%, respectively. Systolic BP (SBP) was higher in children with abdominal obesity compared with those with normal WC (p < 0.01) both in normal and in overweight BMI categories. Similar results were found for diastolic BP (DBP) in normal weight girls (p = 0.032) and overweight boys (p = 0.04). WC was significantly correlated with SBP and DPB in all BMI categories, even after adjustment for age and BMI. Despite these findings, no significant odds ratio (OR) of prehypertension or hypertension for abdominal obesity was found in the normal weight category. On the contrary, in overweight children, prevalence of prehypertension (OR 1.42 [1.1; 1.8]) and hypertension (OR 1.35 [1.1; 1.7]) was higher among abdominal obese children. Similarly, the prevalence of prehypertension was almost two-times higher among obese children with abdominal obesity (11.8% vs. 22.5%); however, no significant OR was found. Conclusions. The ability of WC to detect high-risk normal weight children is controversial. The additional measure of WC among overweight children seems to be relevant in identifying those at increased risk of high BP. Further research with a larger sample size is required in the obese group.