Hypertension is recognized as one of the major risk factors for preventable deaths worldwide. It has been described as a disease of global poverty rather than “disease of affluence”, evident by its high prevalence in low- and middle-income countries (LMICs) compared with the high-income countries.1 The prevalence of pediatric hypertension is rising; especially in low- and middle-income countries (LMICs), and its effect is far reaching as it has been shown that elevated blood pressure (BP) and hypertension in adolescent is associated with lower neurocognitive test scores, tracks into adulthood and is also associated with premature cardiovascular and renal diseases.234 The prevalence of pediatric hypertension in the United States is approximately 3.5% and that of elevated BP approximately 2.2% to 3.5%.5 The prevalence among African children from the systemic review carried out by Crouch et.al6 is 7.5%, 11.4% and 21.7% for hypertension, elevated BP and combined hypertension and elevated BP respectively. The prevalence of adolescent hypertension from across Nigeria ranges from 0.1% in South-west to 17.5% in North-central.7891011

Literature has shown that childhood and adolescent hypertension tracks into adulthood with associated complications that could only be prevented if early interventions were instituted.1221314Yet, the proportion of awareness, treatment and blood pressure control in LMICs, even among adults, is low.15 The lack of routine BP check among the paediatrics population in resource constrained settings like ours, due among others factors, to unavailability of appropriatesize cuffs for the paediatrics age groups6 and the notion that hypertension is an adult disease makes the true burden of it not to be known.

According to the 2017 clinical practice guidelines of American Academy of Paediatrics (AAP), paediatric hypertension is defined as “blood pressure ≥95th percentile for age, sex and height for children from 1-13 years of age, and for adolescent above 13 years of age it is blood pressure of ≥130/80 mmHg”. Also added to the guideline is “Elevated blood pressure” which is blood pressure >90th percentile to <95th percentile or 120/80 mmHg to <95th percentile (whichever is lower) for children aged 1-13 years; and for adolescent above 13 years, it is blood pressure of 120/<80 mmHg to 129/<80 mmHg.5

The study was carried out to determine the prevalence of elevated BP and hypertension among 10-19 years old adolescents attending secondary school across Benue South, Nigeria; to characterise their demographics as well as determine factors associated with the development of high blood pressure among them.

A total of 260 adolescents were recruited with the males making up 50.8% and those of Idoma ethnic group accounting for 91.2%. The mean age was 13.65±2.01 years. The early adolescence group (10-13 year) accounted for 46.5% followed by the middle adolescence group with 45.4%. The mean weight, height and BMI of the participants were 42.9±9.34, 153.4±10.95 and 18.08±2.37 respectively. Table 1 shows the sociodemographic characteristics. None of the participants had ever smoked cigarette and only one (0.4%) agreed to have ever taken alcohol.

Elevated blood pressure was found among 14(5.4%) of the respondents while 6(2.3%) had hypertension. The highest prevalence of elevated blood pressure/hypertension 12(60%) was among the middle adolescence age group of 14-16 years with the females being more prone (75%) and this was statistically significant at a p-value of 0.02. Table 2 depicts the prevalence of elevated blood pressure and hypertension.

The prevalence of high blood pressure (elevated BP/hypertension) was found to be higher, 15(75%) among the adolescents from Ogbadibo local government area and the difference was statistically significant. The adolescents from the lower socioeconomic class and those with normal BMI percentile had higher prevalence of high blood pressure, 14(70%) and 19(95%) respectively but neither was statistically significant. Eighty-seven (33.5%) of all the adolescents had protein in urine, (+ ) of protein (≥30 mg/dl) on dipstick urinalysis. Eleven out of the adolescents with high blood pressure (55.0%) had proteinuria but this was statistically significant at a p-value of 0.047. Table 3 shows the sociodemographic factors associated with elevated blood pressure/hypertension.

The prevalence of hypertension of 2.3% among the adolescents in Benue South Senatorial zone falls within the documented prevalence range of 0.1-17.5%7891011 among adolescents across Nigeria. It is however lower than the 17.5% recorded by Ejike et al.11from neighbouring Kogi State in North Central Nigeria and the 5.4% from Enugu State in South-east Nigeria.18 The wide range of prevalence from different region of the country could be attributable to different methodologies and definition of hypertension adapted by the various authors. There is no national guideline for the diagnosis of hypertension among children hence various authors use different international guidelines that is prevalent at the time of their study. The obvious fact from this finding is that hypertension is a health problem among adolescents in Benue South as reported from other parts of the country but it requires intentionally seeking for it. This underscores the need to incorporate regular blood pressure monitoring among adolescent into school health programme for early detection and intervention, knowing the deleterious effects of long standing hypertension on the health of adolescents.23

The prevalence of elevated blood pressure (pre-hypertension) of 5.4% among the adolescents in Benue South Senatorial zone is similar to the 5% Ezeudu et al9 found in their study from South-east Nigeria but lower than the 22.2% & 25% findings of Ejike et al11from neighbouring Kogi State in North-central Nigeria, the global prevalence of 9.67% documented by Song et al19 from a systemic review and meta-analysis carried out in 2019. The lower prevalence of elevated blood pressure in the present study as against the findings from the neighbouring State of Kogi might be due to differences in the age groups and methods of blood pressure measurement used. The Kogi study was among 13-18 years old and the blood pressure was measured using an automated device. It has been documented that oscillometric (automated) method of blood pressure measurement tend to overestimate the blood pressure when compared with the standard blood pressure measuring method of using mercury sphygmomanometer which was used in the present study. Also the definition of elevated blood pressure in that study was based on the 2004 fourth report whereas in this study it was based on the 2017 AAP guidelines.

The sociodemographic characteristics of those with elevated BP or hypertension also showed variations from other studies. The participants in mid-adolescence had the highest proportion of those with elevated BP/HTN, and this is similar to the findings of the study done by Ator et al.20and by Okagua et al.21 while it is at variance with Odunaiya et al.,22where hypertension was more common in late adolescence. The mid-adolescence period coincides with the peak of puberty with its rapid physical changes as well as emotional and hormonal fluctuations. These pubertal changes could be responsible for the higher prevalence of high blood pressure observed among the group. Nonetheless, there is need for routine blood pressure monitoring across the various age groups.

Three-quarters of those with high blood pressure (elevated BP/HTN) were females; this is similar to the report by Ezeudu et al.,9 Ujunwa et al.,19 and Uwaezouke et al.23 where females had a higher prevalence of hypertension compared to males. Females generally tend to have earlier onset of puberty than males, and this could contribute to why the females have higher prevalence of high blood pressure. Okpokowuruk et al8 however, found that gender was not significantly associated with development of hypertension. The lower socioeconomic class also have the highest proportion of adolescents with high blood pressure compared to the middle socioeconomic class and this is similar to what Akinkugbe et al.24 and Kacsmarek et al.25 reported in their respective studies. Low socioeconomic class is linked to poor nutrition, chronic stress and poor access to healthcare, which ultimately leads to prehypertension/hypertension. However, Mahlati et al.26from South Africa, did not find any association between socio-economic status and prevalence of hypertension among adolescents in their work.

Almost all of the respondents that have elevated BP/hypertension have a normal BMI for age, a finding that is in contrasts to earlier studies which showed that obesity is a predictor for elevated BP/hypertension.^23,27,28,29 It is however consistent with the findings of Ajite et al30 and Rosner et.al31 who found that at lower BMI, black adolescents have higher BP and more prevalence of hypertension than white adolescents. This underscore the importance of screening for elevated blood pressure among all adolescents, irrespective of whether the adolescent appears healthy, underweight or obese.

The presence of significant proteinuria (+), {≥30 mg/dl} among the adolescents had a correlation with elevated BP/hypertension just as demonstrated by Adekanubi et al32and Rahama et al33 who found proteinuria to be an independent risk factor for elevated BP and hypertension. It is however in contrast with the findings of Ezeudu et al34and Ajite et al30 among adolescents from Eastern and Western Nigeria respectively; and Battaglia et al35among Italian adolescents. They found no correlation between proteinuria and high blood pressure.

The prevalence of hypertension and elevated blood pressure among the adolescents in Benue South was 2.3% and 5.4% respectively. Being a female, in mid-adolescence age group, from the lower socioeconomic class and Ogbadibo LGA predisposes to higher prevalence of high blood pressure. High blood pressure was also found to be associated with presence of significant proteinuria.

Regular blood pressure measurement should be incorporated into school health programmes and at every opportunity that brings an adolescent in contact with health facility.

The study was supported by the 2023 TETFUND Institutional Based Research (IBR) funding (FX302-IBR)