Background: Blood pressure in childhood is the most powerful predictor of hypertension in adults. Norms for blood pressure in children are based on the age- and height-specific distribution of blood pressure in a reference sample of healthy children.
Methods: We performed a cross-sectional survey of school-children in the age group 5 to 14 years in south Delhi and studied the distribution of systolic and diastolic blood pressure in 8293 children (4623 boys and 3670 girls). Blood pressure was measured in all children with a mercury column sphygmomanometer using a standardized technique. The first and the fourth Korotkoff sounds were taken as indicative of the systolic and the diastolic blood pressure, respectively. Height percentiles were computed for the study sample for every one-year sex-pooled group. Multiple linear regression was then performed for every one-year group in order to estimate the 90th and 95th percentiles of systolic and diastolic blood pressure according to percentiles of height.
Results: Age and height, but not gender, emerged as the principal determinants of systolic and diastolic blood pressure in multivariable linear regression analyses. Age- and height-specific 90th and 95th percentile values of systolic and diastolic blood pressure were estimated, which enabled us to categorize children into 'normal', 'high normal' and 'high' blood pressure groups.
Conclusions: We present age- and height-specific reference values for blood pressure of Indian children based on a large study sample. The use of these standards should aid the identification of children with high blood pressure.