Abstract:

Background: High blood pressure (BP) among children and adolescents is increasingly becoming common. However, prevalence estimates vary widely partly due to variations in study setting (rural/urban), method of BP measurement and definition of high BP. Few studies have used unattended automated office BP measurements (AOBP) and to the best of our knowledge no study in Africa has used 24-Hour ambulatory BP measurement (24-Hour ABPM) for confirming high BP among adolescents.

Objectives: To estimate prevalence of high BP using unattended automated office BP (on two separate occasions) and 24-hour ABPM for confirmation of sustained high BP and ruling out white coat hypertension.

Methods: From April to September 2018, we enrolled 500 adolescents aged between 11 and 15 years from 3 public secondary schools in Mwanza city. Using standard procedures, we obtained 3 unattended AOBP readings on the first occasion. On the second occasion -- within 2 weeks - 3 unattended AOBP were obtained from participants who had high BP on the first occasion. Within a month, 24-Hour ABPM was done on participants with persistently high BP on the second occasion.

Results: The median age (Interquartile range) of participants was 14.0 (13.0 -- 15.0) years and 56.6% of participants were females. Most participants (91.2%) had their BP measured for the first-time following participation in this study. Based on three BP measures taken during the first occasion, prevalence of high BP was 36.6% (183) and 25.6% (128) using first BP measure and average of last two BP measures, respectively. On the second occasion, 10.2% (51) had persistently high BP using average of last two readings. 2.6% (13) had sustained high BP using 24-Hour ambulatory BP measurement.

Conclusion: White coat hypertension is common among adolescents in Tanzania. School based screening for high BP is feasible and could be used for cardiovascular health promotion.