Reference values for blood pressure of healthy Sri Lankan Tamil children in the Jaffna district

Abstract

Introduction: Increasing trend of childhood obesity leads to high blood Pressure (BP) in children and adolescents. Ethnic differences in BP have been reported. Normal BP values of Sri Lankan Tamil children are not available. Objective: To measure BP of healthy Sri Lankan Tamil children in the Jaffna district to get normal BP values and to correlate them with anthropometric measurements. Method: A population based descriptive cross sectional study was carried out among children and adolescents (950 boys, 972 girls) aged 6 to 18 years in schools in Jaffna district. Cluster sampling was applied to classrooms in the schools. The classes were selected by systematic random sampling. Age, height, weight, waist circumference and hip circumference were taken. Body mass index, waist hip ratio and waist height ratio were calculated. BP was measured with a mercury sphygmomanometer. Pubertal stage was assessed with a self-administered Tanner staging scale. Results: Mean of the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of boys and girls increased from 98/70 mm Hg and 99/70 mm Hg to 107/73 mm Hg and 107/73 mm Hg until 10 years, decreased slightly up to 13 years (101/64 mm Hg and 102/63 mm Hg) and increased until 18 years to 119/76 mm Hg and 111/70 mm Hg. From the age of 15 years, boys had higher SBP and DBP than girls (p<0.05). SBP had significant (p<0.001) positive correlations with pubertal staging and all measured anthropometric parameters. Highest correlation was observed with weight (0.522). A normogram for BP was constructed with age and height.