The Relation between Blood Pressure and Body Mass Index in Iranian School Age Children

Background: Association between body mass indexes (BMI) and blood pressure have been observed, but remains poorly understood. BMI is shown to be a measure of overweight status and is applicable to all populations. In this crosssectional study we have examined the relationship between the BMI and blood pressure in school age children. Methods: This study comprised of 486 boys and 463 girls at aged from 7 to 14-yrs. We examined the age-adjusted relationship between systolic (SBP) and diastolic (DBP) blood pressures and BMI in three age groups of 7, 11 and 14-yrs. BMI was calculated by dividing the body weight in kg by the square of height in meters (m(2)). At first multiple regression analyses were separately used for SBP and DBP to establish their association with BMI, age, gender and height. The analyses test was then repeated by replacing BMI by adjusted BMI. Result: SBP and DBP were positively and significantly related to BMI (P<0.01). According to multivariate regression analysis, SBP and DPB showed significant associations with age and weight with respective relation coefficient of 0.569 and 0.469 for BMI, SBP and DBP. Conclusion: The results of this study showed that BMI was highly associated and linearly related with both systolic and diastolic blood pressures in Iranian school-age children.