Correlation of Anthropometric parameters and Blood pressure in children between 8 -12 years

Abstract

Background: Blood pressure is a major determinant of health and cardiovascular morbidity. It is determined by a number of factors including BMI. Being a lifestyle disease, it has its roots in early childhood. The on-going pandemic of childhood obesity has resulted in a marked increase in cases of childhood hypertension. Therefore we studied the prevalence of overweight and obesity, the defining parameters and their correlation with blood pressure in school children. Methods: A cross sectional observational study was conducted in three schools in Mumbai, with children largely from middle class population. Dietary history, physical activity details were noted. Anthropometric details such as weight, height, BMI, waist circumference, hip circumference, triceps skinfold thickness were noted. Blood pressure was recorded after being seated for 10 minutes. Statistical analysis was done to study correlation between anthropometry and blood pressure. Results: 981 students were examined. 57.8% had normal BMI, 12.33% and 16.82% had severe thinness and thinness respectively. 9.07% and 3.98% were overweight and obese respectively. Mean Waist Hip Ratio (WHR) for boys and girls was 0.88 and 0.82 respectively. Mean Waist Height Ratio (WHtR) for boys and girls was 0.45 and 0.43 respectively. Mean Triceps Skin Fold Thickness (TSFT) for boys and girls was 5.47 mm and 6.31 mm respectively. 25% of children with systolic prehypertension were overweight, 6.66% were obese. 37.2% of children with diastolic prehypertension were overweight, 16.27% were obese. 32.7% of children with systolic stage 1 hypertension were overweight, 20% were obese. 47.05% of children with diastolic stage 1 hypertension were overweight, 26.47% were obese. 37.1% of children with Systolic stage 2 hypertension were overweight, 37.14% were obese. 30.76% of children with diastolic stage 2 hypertension were overweight, 23.07% were obese. The prevalence of both systolic and diastolic hypertension increased curvilinearly with increasing WHR, WHtR and TSFT. WHR at the cutoff of 0.85 revealed a sensitivity of 60 % and specificity of 53%. Positive predictive value was 11.4% and negative predictive value was 92.9%. WHtR at the cutoff of 0.45 showed a sensitivity of 76.7 % and specificity of 70%. Positive predictive value was 20.5% and negative predictive value was 96.7%. TSFT at the cutoff of 9 mm had a sensitivity of 73.3 % and specificity of 84.3%. Positive predictive value was 32% and negative predictive value was 96.9%. Conclusions: BMI, WHR, WHtR and TSFT had a strong positive correlation with systolic and diastolic blood pressure. WHtR was more sensitive and TSFT was more specific in detecting hypertension. As a predictor of hypertensiom, TSFT was the most useful single parameter in our study.