Blood Pressure Standards for Shiraz (Southern Iran) School Children in Relation to Height

OBJECTIVE This study aims at providing local reference values for blood pressure by height and determining distribution pattern of systolic and diastolic blood pressure in 6.5-11.5 elementary school children for the first time in Shiraz (Southern Iran). METHODS Height, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured with standard methods in 2270 healthy school children (1174 boys, 1096 girls) who were selected by multi-stage random sampling in 2003-2004 academic years. We produced blood pressure percentiles by height percentiles using Healy-Rasbash-Yang method. FINDINGS The blood pressure (both systolic and diastolic) tends to increase with age, but after adjusting the measurements for height no significant correlation was found between either systolic blood pressure or diastolic blood pressure and age (r=-0.03 and P=0.15 for systolic blood pressure, r=-0.005 and P=0.8 for diastolic blood pressure). Then systolic and diastolic blood pressure percentile values by age and height percentiles, and blood pressure smoothed centiles by height in 6.5-11.5 years school children were derived. CONCLUSION Due to genetic, cultural and environmental differences among populations, it is suggested to use local blood pressure standards in Iran. We produced blood pressure percentiles by height instead of age because it seems that it would lead to better evaluation for real hypertensive diagnosis.