RESUMEN
The objective of this study was to describe the prevalence, correlation, and association of undernutrition and obesity with high blood pressure (HBP). One thousand five hundred seventy (1570) students (808 boys and 762 girls), aged 7-12 years, from João Pessoa, Paraíba (Northeastern Brazil) participated. Measurements of stature, body weight, skinfolds [triceps (TS) and subscapular (SS)], upper-arm circumference (UAC), upper-arm fat area (UAFE), total upper-arm area (TUAA), and BP were taken. Four criteria were adopted to classify undernutrition and obesity. HBP was defined as systolic BP (SBP) and/or diastolic BP (DBP) values >or=90th percentile. Analysis of covariance, Spearman's correlation, logistic regression, and multiple linear regression were used. In the logistic regression model, undernutrition was not associated with HBP; however, the chances of HBP increased when two or more obesity indicators were present [boys: odds ratio (OR) = 2.08, 95% confidence interval (CI 95%) = 1.26-3.41; girls: OR = 2.26, CI 95% = 1.44-3.55]. In the multiple regression, the BMI, SS, and UAFE explained 15% of the variance of high SBP (r (2) = 0.153) in boys, whereas the body mass index (BMI) and TUAA accounted for 16% of the variance of the SBP (r (2) = 0.166) in girls. The DBP was influenced by the SS in boys (r (2) = 0.022) and the TUAA (r ( 2 ) = 0.054) in girls. There was an association between obesity and HBP. The BMI, SS, and UAFE in boys and the BMI and TUAA in girls explained approximately 16% of elevated SBP.