OBJECTIVE: To evaluate the relationship between body mass index, overweight, and blood pressure among South African rural children and adolescents. METHODS: The sample involved 1,172 schoolchildren (541 boys and 631 girls) aged 10 to 16 years. Stature, body mass, and skinfolds were measured using standard procedures. Overweight was defined by body mass index for gender and age. Blood pressure was monitored in each child three times using validated electronic devices (Omron HEM-705 CP, Device, Tokyo, Japan). Hypertension was determined as the average of three separate blood pressure readings, in which the systolic or diastolic blood pressure was ≥90th percentile for age and sex. Descriptive statistics were calculated for all variables. RESULTS: The prevalence of overweight was 5.5% for boys and 4.4% for girls. The children who had systolic blood pressure >90th percentile ranged from 2.3 to 5.9%. The likelihood of hypertension development among children is noticeable at age 10 for both boys and girls (0.2 and 0.1%, respectively), and ranged from 0.2 to 1.7% for boys and 0.1 to 1.2% for girls. Collectively, the prevalence of hypertension was 4.1 and 2.8% for boys and girls, respectively. Blood pressure correlated positively with stature, body mass, body mass index, body fat, and sum of skinfolds (p<0.001). CONCLUSIONS: Blood pressure increased with age in both genders. The routine measurement of blood pressure, as part of physical examinations of schoolchildren, is crucial for early prevention and intervention programs.
overweight; body mass index; subcutaneous fat; blood pressure; South Africa
