Oscillometric blood pressure by age and height for non overweight children and adolescents in Lubumbashi, Democratic Republic of Congo.

Background: The diagnosis of hypertension in children is complex because based on normative values by sex, age and height, and these values vary depending on the environment. Available BP references used, because of the absence of local data, do not correspond to our pediatric population. Accordingly, our study aimed to provide the BP threshold for children and adolescents in Lubumbashi (DRC) and to compare them with German (KIGGS study), Polish (OLAF study) and Chinese (CHNS study) references.

Methods: We conducted a cross-sectional study among 7523 school-children aged 3 to 17 years. The standardized BP measurements were obtained using a validated oscillometric device (Datascope Accutor Plus). After excluding overweight and obese subjects according to the IOTF definition (n = 640), gender-specific SBP and DBP percentiles, which simultaneously accounted for age and height by using an extension of the LMS method, namely GAMLSS, were tabulated.

Results: The 50th, 90th and 95th percentiles of SBP and DBP for 3373 boys and 3510 girls were tabulated simultaneously by age and height (5th, 25th, 50th, 75th and 95th height percentile). Before 13 years the 50th and 90th percentiles of SBP for boys were higher compared with those of KIGGS and OLAF, and after they became lower: the difference for adolescents aged 17 years was respectively 8 mmHg (KIGGS) and 4 mmHg (OLAF). Concerning girls, the SBP 50th percentile was close to that of OLAF and KIGGS studies with differences that did not exceed 3 mmHg; whereas the 90th percentile of girls at different ages was high. Our oscillometric 50th and 90th percentiles of SBP and DBP were very high compared to referential ausculatory percentiles of the CHNS study respectively for boys from 8 to 14 mmHg and 7 to 13 mmHg; and for girls from 10 to 16 mmHg and 11 to 16 mmHg.

Conclusions: The proposed BP thresholds percentiles enable early detection and treatment of children and adolescents with high BP and develop a local program of health promotion in schools and family.