European Journal of Cardiovascular Medicine

The long, steady and slow course of hypertension in adults also suggests that it perhaps had its origin in childhood, but had probably gone undiagnosed during this period, only to manifest itself during adulthood1

The prevalence of childhood hypertension varies worldwide from 1-12%. In India, the data on prevalence of childhood shows prevalence ranging from 1% to 7.6%2. The reasons for the recent trends of increasing prevalence of hypertension among children are attributed to obesity, decreased physical activity, increasing stress and change in dietary habits, which are modifiable risk factors3. Hence, detecting prehypertension early in childhood and bringing about changes in the lifestyle (modifiable risk factors) can lead to prevention of development of essential hypertension in the adulthood. This decreases the cardiovascular disease burden on the society.

Obesity is a rapidly growing pandemic encompassing many complexities and involves almost every organ of the body. Obesity must be dealt as an issue that affects the society which encompasses the interactive relationship between environment, biology and behavior rather than just as a single medical illness4. The incidece of overweight and obesity in the pediatric population is on the rise across the world. This is true to all the groups of society irrespective of the income bracket1.

The ‘developmental origins of adult disease’ hypothesis, often called the ‘Barker hypothesis’ states that adverse influences early in development, and particularly during intrauterine life, can result in permanent changes in physiology and metabolism. This results in increased metabolic disease risk in adulthood. In particular, links are well established between reduced birth weight and increased risk of coronary heart disease, diabetes, hypertension and stroke in adulthood6

The trends of the prevalence of overweight in children aged 5-17 years around the globe puts a projection of rising Global overweight prevalence from 13.9% in 2010 to 15.8% in 20257. On the assumption of continued population growth given by the World Bank, this would translate to a rise from some 219 million children in this age group in 2010 to 268 million children by 20257. The Indian Medical Association (IMA) issued a letter named “Childhood obesity a major public health crisis today” dated 25-10-2017 which stated that there are a staggering 14.4 million obese children in India.

As a consequence of excess weight, abdominal obesity is associated with cardiovascular risk factors and metabolic disorders in adulthood, which may already be present in childhood8. Abdominal obesity is understood as the accumulation of fat in the abdominal region assessed by an anthropometric and/or body composition measure that shows a value above a specific and sensitive cutoff point9.

Due to the emergence of Covid-19, there have been instances of complete lockdown globally. These lockdowns have significantly affected the lifestyle of the children, who have switched to E-learning at home leading to sedentary lifestyle, unhealthy eating and behavior pattern. These changes have led to increase in the burden of overweight in children from 41.1%, 21.4%, 13% pre lockdown in the USA10, China11, India12 respectively to 44.5%, 24.6%, 17.8% post lockdown.

Hence, this study was done to find out the prevalence of hypertension, in the school going children of age group 9-16 years in Bagalkot city which is located in Northern part of Karnataka, India.

This cross-sectional study was conducted among School Children aged between 9-16 years from schools in Bagalkot. Study period was 1.5 years, Jan 2020- June 2021

Sample Size:

Sample size estimation done using open Epi software version 2.3.1

Sample size= n= 1155,

Sample size approximated to 1200

Inclusion Criteria:

• Asymptomatic children aged 9-16years willing to participate in the study were included in the study group.

Exclusion Criteria:

1. Children suffering from chronic illness. (eg: Endocrine diseases, cardiovascular diseases, renal diseases).
2. Children taking long term medications which may affect blood pressure such as antihypertensive drugs, corticosteroids, antidepressants, anxiolytics, anti- inflammatories.
3. A child whose Parents did not consent for their participation in the study.

Methodology:

1. After obtaining approval from ethical committee of SNMC and HSK Hospital

2. Appropriate permission from BEO of Bagalkot were obtained

3. All the schools in Bagalkot including government and private school were enlisted and 20% of the schools were selected randomly including private and government schools. Children who are aged between 9-16 years and belonging to the selected schools were included in the study

Schools visited:

1. Basaveshwara English Medium Higher Primary School.
2. Basaveshwara Kannada Medium Higher Primary School Motagi B.V.V.S Primary school.
3. Sri Basaveswar Girls High School
4. Permission of the head of the institution was taken. All the children were given the parent consent form (both in Kannada and English) to be taken home and to be signed by the parent. The children who got the consent form signed and present on the day of visit were included in the study.
5. The number of school children from each school were selected proportionate to the size of school
6. On the day of visit, family history of hypertension, Ischemic heart disease, diabetes and stroke was taken. Data about diet, daily exercise and amount daily screen time were asked and recorded. Vitals were measured. A thorough general physical examination and examination of the cardiovascular system were carried out, before blood pressure measurements were made. During the abdominal examinations both lumber regions were palpated for the presence of any lump, bruit was looked for over the flanks and presence of organomegaly if any was noted. Anthropometric indices were measured and recorded. The method of recording anthropometric indices is shown below: -

Blood pressure

The measurement of blood pressure was carried out in quite atmosphere. “Diamond LED Deluxe Mercury free Sphygmomanometer” Model: BPDG 141 was used to measure Blood Pressure using auscultatory method The methodological recommendations of task force were used for screening of blood pressure.

Three measurements were taken at intervals of five minutes and mean of 3 reading was recorded. All the readings were made by same observer to avoid inter observer variation.

The percentile charts based on gender, age and height provided by NHBPEP were used for classification of blood pressure.

For children aged < 13 years

• Hypertension

Average SBP and/or DBP of 3 readings ≥95th percentile for that age, sex and height.

Hypertension further divided into

1. Stage 1 hypertension: BP >95th to 99th percentile

1. Stage 2 hypertension: BP >99th percentile + 5 mm of Hg

• Pre hypertension

Defined as average SBP and/or DBP levels that are greater than or equal to the 90th centile, but less than the 95th percentile.

or if BP exceeds 120/80 mmHg even if below 90th percentile up to <95th percentil

Assessment tools:

Statistical analysis:

Data were entered in MS-Excel and analyzed in SPSS V25. Descriptive statistics were represented with percentages for qualitative data, Mean with SD or Median with IQR for quantitative data. Shapiro wilk test was applied to find normality. Chi-square test, Fisher Exact test was applied for comparison of proportions. ANOVA, Independent t-test, Man-whitney U test was applied for comparison between means and medians. ROC curve was drawn. Area under the curve was calculated. Sensitivity and specificity were calculated. P<0.05 was considered as statistically significant.

During the Study period January 2020 to June 2021 1,256 School children from 6 different schools in Bagalkot were included in the study. The data obtained was statistically analyzed and the results are presented in a diagrammatic manner below

Table No 1: Gender Wise Distribution of The Children

Among the 1256 children included in the study, 706(56.2%) were males and 550(43.8%) were females

Table No 2: Age Wise Distribution Of Children

Age wise, maximum number of children were seen in the age group of 15-16 years. Out of 1256 children, 675(53.7%) children were in the age group 15-16 years, 462(36.8%) children were in the age group 13-14 years, 119(9.5%) were seen in the age group 9-12 years.

Out of 1256 children, 1152(91.7%) children belonged to Hindu religion, 104(8.3%) children belonged to Muslim religion.

Table No 3: Family History Of Hypertension

Among 1256 children, none of the family members of 1133(90.2%) children had hypertension, fathers of 107(8.5%) children had hypertension, mothers of 12(1.0%) children had hypertension, and both parents of 4 (0.3%) children had hypertension.

Out of 1256 children, none of the family members of 1163(92.6) children had diabetes, fathers of 77(6.1%) children had diabetes, mothers of 16(1.3%) children had diabetes.

Table No 4: Family History of Ischemic Heart Disease

None of the family members of 1252(99.7%) children had ischemic heart disease and family members of 4(0.3%) children had ischemic heart disease. None of the family members of the 1256(100%) children had Stroke.

Out of 1256 children, 705(56.1%) children had mixed diet, 551(43.9%) children had Vegetarian diet

Out of 1256 children, 1140(90.8%) children reported to do some exercise or had some form of physical activity daily and 116(9.2%) children reported to have not done daily exercise or some form of physical activity.

.

Table No 5: Distribution Based On Daily Screen Time

Out of 1256 children, 737(58.7%) children reported that they had 30 - 60 minutes of screen time daily, 353(28.1%) children reported that they had <30 minutes of screen time daily, 152(12.1%) children reported that they had >60 minutes of screen time daily and 14(1.1%) children reported that they did not have screen time daily

Table No 6: Sbp Wise Distribution

Among 1256 children, SBP was in normotensive range for 1168(93%) children, SBP was in pre-hypertensive range for 36(2.9%) children, SBP was in range of stage 1 hypertension for 39(3.1%) children, and SBP was in range of stage 2 hypertension for 13(1.0%) children

Table No 7: Diastolic Blood Pressure Wise Distribution

Among 1256 children, DBP was in normotensive range for 1056(84.1%) children, DBP was in pre-hypertensive range for 142(11.3%) children, DBP was in range of stage 1 hypertension for 46(3.7%) children, and DBP was in range of stage 2 hypertension for 12(1.0%) children.

Table No 8: Prevalence Of Hypertension In Children

Prevalence of hypertension was found to be 6.3% (n=79), prevalence of prehypertension was found to be 11.9% (n=149) and 1028 (81.8%) children were normotensive

The significant increase of hypertension and high blood pressure in pediatric ages is a cause of concern among worldwide health authorities as also among health professionals. The disease is a silent threat to the health of the people all over the world. It is suggested that hypertension has its origin in childhood but goes undetected unless specially looked for in this period.13

Hypertension is a multifactorial disease influenced by genetic, geographic, cultural and dietary patterns.14 Children from families with hypertension tend to have higher pressure than those children form normotensive families.15

Among many risk factors for hypertension, few of them include obesity, family history of hypertension, and change in dietary habits, decreased physical activity and increasing stress.

Blood pressure is considerably lower in children than adults but almost always increases steadily throughout the first two decades of life and the predictive value of childhood blood pressure for the development of hypertension, coronary heart disease, stroke or renal disease in adults is well known.14,16

Children, whose blood pressure is in the higher centiles during their childhood, almost always go on to develop significant hypertension in their adulthoodunless those children are identified early in their childhood and the necessary changes are made to the lifestyle.17

Prevalence of hypertension

In the present study, the prevalence of hypertension was found to be 6.3% and prevalence of prehypertension was found to be 11.9%. In the other studies done in the children, the prevalence of hypertension was found to be in the range of 0.49% to 12%. Savitha et al., Mane et al. and Patel et al. reported similar prevalence of hypertension in their studies. However, Irgil et al.18, Paradis et al.19, Soudarssanane et al.20 reported higher prevalence of hypertension in their studies. There were reports of lower prevalence of hypertension in the studies conducted by Sinaiko et al.21, McNiece et al.22.

Table No 9: Prevalence Of Hypertension In Various Studies

The results of the present study show that there were very little differences in the mean systolic blood pressure and mean diastolic blood pressure in all age groups between girls and boys. These differences were statistically insignificant with p>0.05 in all the age groups

Similar results were observed by Moura et al23 that sex has no significant association with systolic blood pressure. Krishna et al.24 in their study observed that age and height but not gender, are important determinants of blood pressure. Bernard Rosner et al.25, P Muntner et al.26 also observed similar relation in their study.

Present study is comparable to similar observations noted in studies done in Mysore city by Savitha M R et al.27 and by Sharangouda Patil et al.28 in Gulbarga city where there was no relationship between gender and blood pressure.

Age limit of children in this study was from 9-16 years. The findings of the present study revealed that rise in BP (both SBP & DBP) were directly proportional to increase in age. Similar observation was made by Anand et al.13, Taksande et al.16. There is a significant correlation between different age groups and hypertension with P=0.002 which is statistically significant. It can be attributed to the changing levels of hormones with age.

In the present study 10.6% (n=13) of children with family history of HTN were hypertensive and 19.5%(n=24) of children were prehypertensive with P = 0.003

indicating that there is significant correlation between family history of HTN and Hypertension in children. A study done by Zeena Salman et al. found 40% children with family history of HTN were hypertensives.29 Anand et al.13 found 5.9% of children with family history of HTN were hypertensive. Menghetti et al. found that children of mothers with hypertension have a two-times greater risk of having blood pressure values in the upper 90th percentile.30 This can be attributed to shared environmental hypertension and shared gene pool by the family.

Hence, the steps taken to curb childhood hypertension must also include parental education about hypertension and the measures to take to avoid hypertension in their children.

In the present study, prevalence of undernourishment was found to be 26.1% in the study population. prevalence of undernourishment was more in the studies done by Sukonthachit et al.31 and Burgos et al.32 which was 8.9% and 12.2% respectively.

In the present study, prevalence of obesity was found to be 2.2%. Prevalence of obesity in the studies published by Pan et al. 33 and Jakab et al.34 was 7.9%, 6.6% respectively. Prevalence of obesity is less than the compared studies.

In the present study, among the children who reported to have daily screen time of >60 min, prevalence of hypertension was found to be 9.3%. There was statistically significant correlation between increased screen time and prevalence of hypertension with P=0.02. This is in agreement with studies by Cassidy et al.35, Gopinath et al.36.

Eating habits of the children is influenced by television. Foods frequently advertised on TV are more commonly consumed than foods not frequently advertised, and these advertised foods are usually high in fat, sugars and salt. Intake of high fat and high salt foods may contribute to the link between TV viewing and high BP in children.

The current study evaluated school children aged 9-16 years and found that the prevalence of hypertension and prehypertension to be 6.3% and 11.9% respectively. Amount of daily screen time significantly correlated with Obesity. Hypertension correlated significantly with age, amount of daily screen time, positive family history of hypertension.

Hence, the prevention of hypertension in children should include counseling to discourage screen time, and promoting more physical activity. The targeted questionnaire in community health programs and in office settings should include questions on a family history of hypertension, amount of daily screen time, junk food consumption, sodium intake daily and high-calorie diet, all of which are red flags for hypertension. 

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