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ORIGINAL ARTICLE
Year : 2022  |  Volume : 25  |  Issue : 4  |  Page : 386-390

Blood pressure profile, prevalence of hypertension and associated familial factors in school children in Accra, Ghana


1 Department of Child Health, University of Ghana Medical School, College of Health Sciences, University of Ghana, Kumasi, Ghana
2 Department of Community Health, University of Ghana Medical School, College of Health Sciences, University of Ghana, Kumasi, Ghana
3 Department of Child Health, School of Medicine and Dentistry, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana

Date of Submission22-Sep-2021
Date of Acceptance30-Dec-2021
Date of Web Publication19-Apr-2022

Correspondence Address:
Dr. T J Afaa
Department of Child Health, University of Ghana Medical School, Korle Bu Teaching Hospital, Accra
Ghana
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/njcp.njcp_1832_21

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   Abstract 


Background: Essential hypertension, which is hypertension without a known cause, runs in families. Children from families with hypertension are likely to have a higher blood pressure than children from normotensive families. Aim: The aim of this study was to find the prevalence of hypertension and the associated family risk factors for hypertension in the school children. Patients and Methods: This prevalence study was conducted in six first-cycle schools in Accra, Ghana. School children between the ages of five to fourteen years were recruited into the study. A questionnaire, which gathered information on demographic data, family history, and risk factors associated with childhood hypertension and the child's clinical data, was used. An average of three blood pressure readings with an automated sphygmomanometer and height measurement was taken for each child. Blood pressure was categorized as normal, pre-hypertension, and hypertension using the Centers for Disease Control and Prevention (CDC) reference charts. Results: A total of 600 school children comprising 358 (59.7%) females and 242 (40.3%) males were studied. Fifty-one (8.5%) school children had elevated blood pressure. Of these, 15 (2.5%) had hypertension, while 36 (6.0%) had pre-hypertension. Two hundred and thirty-eight participants had a family history of risk factors for hypertension. Twenty-five (10.5%) children with risk factors (family history of hypertension, diabetes mellitus, obesity, stroke) had elevated blood pressure (BP) compared to 7.2% of those without risk factors. Conclusion: Urgent positive lifestyle transformations, which should start from school to reduce the incidence of hypertension in children.

Keywords: Blood pressure, children, hypertension, and family history


How to cite this article:
Afaa T J, H Seneadza N A, Ameyaw E, Rodrigues O P. Blood pressure profile, prevalence of hypertension and associated familial factors in school children in Accra, Ghana. Niger J Clin Pract 2022;25:386-90

How to cite this URL:
Afaa T J, H Seneadza N A, Ameyaw E, Rodrigues O P. Blood pressure profile, prevalence of hypertension and associated familial factors in school children in Accra, Ghana. Niger J Clin Pract [serial online] 2022 [cited 2022 May 23];25:386-90. Available from: https://www.njcponline.com/text.asp?2022/25/4/386/343462




   Introduction Top


Blood pressure values are dynamic, and the interpretation of blood pressure levels in children requires consideration of the child's age, sex, and height.[1] Hypertension in children is defined as an average systolic and diastolic blood pressure equal to or greater than the 95th percentile for age, sex, and height measured on at least three different occasions, while pre-hypertension is a blood pressure level greater than the 90th percentile but less than the 95th percentile for the age, sex, and height.[2] In 2017, the definition for hypertension in adolescents aged 13–17 years was reviewed as BP of at least 130/80 mmHg, with no adjustment age, sex, or height.[3] The updated definition was used to categorize the BP levels in this study.

Essential hypertension was common in the pediatric population than was previously thought.[4] Data from Africa[5] showed that hypertension has been increasing in the pediatric population in the past three decades, and this has implications for public health.

It is well established that essential hypertension runs in families,[6] with children from families with hypertension likely to have higher blood pressure compared to children from normotensive families.[7] If one parent has hypertension, the risk in the children is about 25%, increasing to 45% when both parents are hypertensive.[8] Children with elevated BP have been found to have a significant family history of hypertension, stroke, and diabetes mellitus.[9] Additionally, the parents of children with hypertension were at fifteen times higher odds of having hypertension than parents of children without hypertension.[10]

There are very few studies from Africa[11] on childhood hypertension and its relationship with a family history of hypertension. This study was aimed at estimating the prevalence of hypertension and associated familial factors (family history of hypertension, diabetes mellitus, obesity, stroke) in school children in Ghana.


   Methods Top


Study design and location

This was a cross-sectional prevalence study conducted in six first cycle schools from February to June 2012. School children between the ages of 5 to 14 years were eligible for inclusion in the study while those on medications known to influence blood pressure such as corticosteroid, and antihypertensive drugs were excluded.

Sampling and sample size

Based on the maximum prevalence of hypertension of 48% in the general population,[12] with a design effect of 1.5, 95% confidence level, a 5% margin of error, and a non-response rate of 5%. A statistical two tailed study of N = (z2pq)/d2 was used. Six hundred school children were recruited into the study.

A multistage sampling method was used to select and recruit eligible school children. Out of the 13 Sub Metropolitan Areas (SMA), one SMA was randomly selected through balloting. Schools in Ayawaso West Wuogon SMAs were grouped into circuits, with each circuit containing six schools and one circuit was balloted for. The list of students in each year was obtained from the schools; this was used to recruit participants using systematic sampling. Study procedures were explained to parents or guardians at parents teachers association meetings.

Data collection

The questionnaire, which gathered demographic data, family history, and risk factors associated with childhood hypertension (hypertension, diabetes mellitus, stroke, heart attack, obesity) and the child's clinical data, was used. The parent of participants documented the family history in the questionnaire given to the child. These forms were returned to the class teachers the next day. The day before, the children were clinically examined (fieldwork), all questionnaires were checked for completeness. Incomplete forms were completed with the help of the parents or guardians through the contact number written on the consent form.

An automated sphygmomanometer (Welch Allyn® Blood Pressure Monitor) was used for blood pressure measurements as recommended by the American Academy of Pediatrics.[3] This device has successfully passed the Association for the Advancement of Medical Instrumentation standard requirements and achieved an AA rating by the British Hypertension Society data analysis. It is currently one of the most widely used automated sphygmomanometers in clinical practice.[13]

Each child was seated and made comfortable for 5 minutes, after which the blood pressure was taken using an age-appropriate blood pressure cuff with the right arm placed at the level of the heart. Three blood pressure measurements were taken for each child, and the mean calculated rounded to the whole number. Children with systolic and or diastolic blood pressure at or above the 90th percentile for age, sex, and height using the Centers for Disease Control and Prevention (CDC) reference charts were re-evaluated with a mercury sphygmomanometer. Children with BP greater than the 90th percentile were classified as having pre-hypertension, and those with BP greater than the 95th percentile were classified as having hypertension. The height was measured using a vertical stadiometer (Seca® Instruments Ltd, Hamburg, Germany). A pretest of the instrument was done in Maamobi Prisons Primary School, another first cycle school within the Sub Metropolitan Area.

Data processing and statistical analysis

Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 18.1. Mean values with standard deviations were calculated for age, sex, and blood pressure. Logistic regression analysis was used to predict familial risk factors for childhood hypertension.

Ethical considerations

The study was conducted in accordance with the principles of the Helsinki Declaration with good clinical guidelines. Ethical approval to conduct this study was obtained from the Ethical and Protocol Review Committee of the University of Ghana Medical School with identification number MS-Et/M.6-P. 5.2/2010-11. Permission was obtained from the Ghana Education Service, Ayawaso West Wuogon Sub Metropolitan Director of Education, and heads of the individual schools. Informed written consent was obtained from the parents or legal guardians of selected students, and verbal consent was obtained from children eight years and above. Children who had high blood pressure were referred to the Teaching Hospital for further investigations and management.


   Results Top


Six hundred school children from six schools were enrolled in the study. Of these, 358 (59.7%) were females, and 242 (40.3%) were males, with male to female ratio of 1:1.5. The mean age for females was 10.2 ± 2.5 years, and that of males was 9.9 ± 2.5 years.

Fifty-one (8.5%) school children had elevated blood pressure. Of these, 15 (2.5%) had hypertension, while 36 (6.0%) had pre-hypertension. Amongst those with elevated BP, sixteen (31.4%) children had both systolic and diastolic pre-hypertension, while most (fourteen out of sixteen children) of the hypertension cases had systolic hypertension only. Only one child (0.9%) within the age group of 13 to 14 years had diastolic hypertension. [Table 1] shows the detailed distribution of the prevalence of pre-hypertension and hypertension amongst school children.
Table 1: Prevalence of hypertension and pre-hypertension according to age

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Females in this study had a higher prevalence of both systolic and diastolic pre-hypertension and while the males had a higher prevalence of hypertension, as shown in [Table 2].
Table 2: Distribution of blood pressure categories by sex

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Family history of risk factors and childhood elevated BP

Risk factors in [Table 3] include a family history of hypertension, diabetes mellitus, stroke, obesity, and heart attack. One hundred and twenty-eight (21.4%) children had a single risk factor each, while 110 (18.3%) had multiple risk factors. Twenty-five children (10.5%) with risk factors had elevated BP than children (7.2%) without risk factors as shown in [Table 3]. Elevated BP includes both pre-hypertension and hypertension
Table 3: Association of risk factors and childhood BP

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Elevated BP in [Table 4] includes both pre-hypertension and hypertension. Family history of hypertension is the commonest risk factor amongst school children, while those with a family history of diabetes mellitus had the highest prevalence of elevated BP. School children without a family history of obesity had elevated BP compared to children with such a family history.
Table 4: Family history of risk factors and BP levels of school children

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   Discussion Top


The majority (91.5%) of the study participants had BP values that fell within the CDC normal ranges for their ages, sex, and height.[3]

The prevalence of hypertension of 2.5% in our current study is lower than the prevalence rates of 3.7% in Nigeria,[14] 4.0% in Egypt,[15] and 5% in Sudan.[16] The pooled prevalence rate of hypertension in 25 studies done in African children for the past two decades was 5.5%.[8] These variations in the prevalence rates may be due to methodological differences. In the Nigerian study, the BP was measured with a mercury sphygmomanometer, and the mean of six BP readings was taken as the BP of an individual, and the DBP was taken at Korotkoff IV sound. In Egypt, the researchers used a mercury sphygmomanometer, and the mean of two BP readings was used for individual participants and Korotkoff V sound was used for the measurement of DBP. In the Sudan study, blood pressure was measured twice, manually and digitally and the average was documented for analysis.

The mean BP for both SBP and DBP was higher among females than males. This finding of higher mean BP among females is supported by reports from two other studies conducted in Ghana[17] and Nigeria.[14] However, contrary to the findings of these two African studies[14],[17] and what the current study found, a multiracial study done in the USA showed that males tend to have a higher blood pressure than females.[18] The higher prevalence of elevated blood pressure among females in this study and the other African studies[14],[17] could be due to the fact that these African studies had higher proportions of pre-pubertal females where the BP-lowering effect of the sex hormone oestradiol[19] is not activated or could be due to racial similarity as all the studies were done in West Africa with common ancestry.

Other researchers had noted this pattern of a higher level of pre-hypertension in relation to hypertension in children.[8] Considering that this study population consisted of apparently healthy children, such a result is a cause for concern. The finding of 8.5% of the total study population with elevated blood pressure calls for inclusion and intensification of education on childhood hypertension in school health programs.

Of the 2.5% of participants with hypertension, the majority had systolic hypertension. In the adult population, systolic hypertension is far more common in children than diastolic hypertension. This finding is supported by studies done in Nigeria,[20] Switzerland,[21] and the United States of America,[22] which all reported systolic hypertension in between 88% to 95% of children of similar age groups with hypertension.

The study reveals a high occurrence of risk factors for hypertension-related illness among the families of the study population. Almost 40% of children had at least one risk factor for childhood hypertension in the family.

Family history of hypertension was the most frequent risk factor. This finding is similar to a study done in Port Harcourt, Nigeria, where 24% of school children between the ages of six and twelve years had a family history of hypertension.[11] The finding that 143 (23.8%) school children had a family history of hypertension may even be an underestimation of the true prevalence in Ghana, given the findings by Amoah[23] and Addo[24] of 28% and 30% of the adult population in Ghana with hypertension respectively. In Ghana, illiteracy, ignorance, and belief in spiritual causes of illness limits the discussion of family medical conditions and their diagnosis.[25] A family history of hypertension of 23.8% is low, compared to a systematic review of published studies of hypertension in Ghana from 1973 to 2009 by Addo et al.,[24] which showed a prevalence of up to 55% in adults living in urban areas. It is safe to assume that not all the caregivers in this study knew their blood pressure status. Such a high level of hypertension among family members is worrying not only because of the possibility that the children may be at a higher risk of getting hypertension as adults[9] but also because this study was in young children and their parents need to be healthy and alive for many years. This family history of hypertension supports the view that it is a common disease.

Family history of obesity from this study (8.5%) was low compared to that found by other researchers in Ghana. In a nationwide study in Ghanaian adults, Biritwum et al.[26] found a prevalence of obesity in Greater Accra of 16.1%, while Amoah[27] found an overall crude prevalence of obesity in Accra of 20.2% and 4.6% for adult females and males respectively. The family history of obesity in this study was self-reported, and participants may not necessarily regard or appreciate that they or their family members are obese. In addition, unlike the other risk factors for which medical intervention is likely to have been sought, obesity may just remain undiagnosed or untreated. In some communities, obesity may even be seen as a sign of wellbeing or affluence and not regarded as a risk factor for certain diseases. In such communities in Ghana, weight gain is highly encouraged, and obese individuals are respected or revered.

The association between risk factors and elevated childhood blood pressure in this study echoes other findings in Africa. In Egypt,[15] among adolescents, elevated BP was statistically significantly associated with a positive family history of hypertension and diabetes mellitus but not with a family history of obesity. In Sudan,[16] 40% of children with hypertension had a family history of hypertension compared to 20% of children without such family history.

Limitations

The researchers did not collect data on potential confounders such as family income, place of residence, and risk behaviors.


   Conclusion Top


The prevalence of elevated blood pressure and hypertension among the school children were 8.5% and 2.5%, respectively. About a quarter of the children had a family history of risk factors for hypertension. These findings indicate the need for urgent positive lifestyle transformations, starting from school.

Acknowledgements

The authors are grateful to all the school children in Ayawaso West Wuogon, the teachers, and head teachers within the Sub Metropolitan Area.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Key message

Childhood hypertension is prevalent in children and more so in children with a family history of risk factors for hypertension.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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