Background: To assess the prevalence of hypertension (H), prehypertension (PH), and transient elevated blood pressure (TH) and their relationship with weight class and waist circumference (WC) in an unselected population of Northern Italian children.
Methods: A cross-sectional study was conducted in 5,131 children (5-11 years). Weight class was defined according to the International Obesity Task Force references, H and PH according to the National High Blood Pressure Education Program. A child was classified as having PH or H when systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) at first screening were > or =90th percentile and the mean of three subsequent measures was between the 90th and 95th or > or =95th percentile, respectively. When BP values at the first screening were > or =90th percentile but the mean of three subsequent measures was <90th percentile the child was classified as having TH.
Results: A proportion of 3.4% presented H, 2.7% PH, and 10.4% TH, 20% overweight, and 6% obesity. Weight class and WC were significantly associated to an increased risk of falling into any of the hypertensive categories. In children with TH BP z-scores of the mean of the three subsequent measurements following the first screening were significantly higher than BP z-scores observed in normotensive children (P value <0.001).
Conclusions: Weight class and WC are associated with BP. This is observed not only for H but also for PH, and for nonsustained forms of H. Prospective studies are needed to assess whether children with PH and TH will develop sustained H.