|Year : 2014 | Volume
| Issue : 2 | Page : 78-83
Prevalence of hypertension and variation in blood pressure among school children in rural area of Wardha
Rohan Raosaheb Patil1, Bishan Swarup Garg2
1 Assistant Professor, Department of Community Medicine, Melmaruvathur Adhiparasakthi Institute of Medical Sciences and Research, Melmaruvathur, Kancheepuram, Tamil Nadu, India
2 Director-Professor, Department of Community Medicine, Mahatma Gandhi Institute of Medical Sciences, Sewagram, Wardha, Maharashtra, India
|Date of Web Publication||12-May-2014|
Dr. Rohan Raosaheb Patil
Assistant Professor, Department of Community Medicine, Melmaruvathur Adhiparasakthi Institute of Medical Sciences and Research, Melmaruvathur, Kancheepuram, Tamil Nadu
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Objective: To study the prevalence of hypertension and variation in blood pressure (BP) level among school children in rural India. Design: A cross-sectional study was conducted during the period from April 2010 to March 2012. Setting: Participants comprised of 958 school children (in the age group of 6-16 years) from 83 schools covered by three randomly selected primary health centers. Materials and Methods: After obtaining informed consent from the school principal, a pretested questionnaire was administered and anthropometric measurements were taken. Hypertension was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥95 th percentile for age, gender, and height measured on three distinct occasions. Results: Overall, prevalence of hypertension and was found to be 29 (3.0%). The proportion of hypertension among males was 13 (2.8%) against 16 (3.2%) in females. Overall mean SBP level was 97.2 mmHg and DBP level was 62.1 mmHg. Conclusion: SBP and DBP found to be correlated with the body mass index, waist circumference, which identifies the need of proper dietary changes at individual and family level. Constructed nomogram for study participants show lesser SBP and DBP values for 90 th and 95 th percentiles among Indian children when compared to NHLBP guidelines. This suggests lesser BP cut-off needed to identify maximum hypertensive population among Indian children.
Keywords: Body mass index, Childhood, Hypertension, Nutrition
|How to cite this article:|
Patil RR, Garg BS. Prevalence of hypertension and variation in blood pressure among school children in rural area of Wardha. Indian J Public Health 2014;58:78-83
|How to cite this URL:|
Patil RR, Garg BS. Prevalence of hypertension and variation in blood pressure among school children in rural area of Wardha. Indian J Public Health [serial online] 2014 [cited 2019 Jun 26];58:78-83. Available from: http://www.ijph.in/text.asp?2014/58/2/78/132278
| Introduction|| |
Hypertension is a major long-term health condition and is the leading cause of premature deaths among adults throughout the world.  Around 1 billion of the adult world population was found to have hypertension in the year 2000 and this is expected to increase 1.56 billion by 2025. 
Though hypertension is a problem of adults, but its etiologic process starts in childhood. Evidences across the globe have documented prevalence of childhood hypertension 1-2% in the developed countries and 5-10% in the developing countries.  The prevalence of hypertension in various Indian studies ranges from 0.96% to 11.4%, respectively. 
Early diagnosis of hypertension is necessary to initiate preventive measures but this seems difficult due to the lack of symptoms. Even though, it is proved that even asymptomatic adolescents with high blood pressure (BP) elevation can have evidence of target organ damage.  The factors known to affect BP among children include age, sex, body size, race/ethnicity, obesity, and socioeconomic status. ,, Reference norms developed for one particular population may not be applicable to other. Currently, the fourth report from the national high bp education program working group on children and adolescents provide updated recommendations for diagnosis, evaluation, and treatment of hypertension. The new BP tables based on normative distribution of BP in healthy children includes 50 th and 99 th percentiles of BP values along with earlier 90 th and 95 th percentile values. 
In Indian, setting few efforts have been done to obtain local reference data for any observed BP values. , In view of the scanty evidences present study was planned (1) to find out the prevalence of hypertension among school children (2) to find the distribution of BP as per age, sex and anthropometric variables and (3) to prepare BP nomogram as per age and sex.
| Materials and Methods|| |
Study design and setting
Present cross-sectional study was carried out from April 2010 to March 2012 in three randomly selected Primary Health Center areas of Wardha District; namely Anji, Talegaon and Kharangana (Gode).
In the start all schools from three Primary Health Center areas were selected for the study. However investigator was able to get permission in 83 schools from area. School going children aged between 6 and 16 years were included in the study. Numbers of study participants from each school were selected by population proportionate to size sampling method (as per the strength of the respective school). Then from each school study participants were selected by systematic random sampling method.
Considering the lowest prevalence of hypertension of 2.5% as reported by Mohan et al.,  alpha error of 5%, 1% absolute allowable error and power (1-β) of 80%, the sample size calculated was 958. From the sampling frame of 19,436 students, at last 958 students were selected for study.
Institutional ethical clearance was obtained before starting the study. Permission from school authorities was sought after explaining the objectives as well as the method of study. In case of minor subjects, the consent was taken from their school teachers and assent was obtained from the subject. The interview schedule included information on socio-demographic variables and nutritional status. The age was determined to the nearest birth date from the school registration record.
All BP measurements were carried out by one physician using a standard mercury sphygmomanometer (Diamond Co. Industrial Electronics and Allied Products, Pune, Maharashtra). The study subject was seated at rest prior to measurements. Readings were taken on the right arm. A cuff of the appropriate size was selected on the basis of upper arm circumference. BP was measured three times, over a period of 10 min. The average of all three readings was used to represent the individual's BP. Pre-hypertension in children was defined as average systolic blood pressure (SBP) or diastolic blood pressure (DBP) levels of 90 th percentile or higher but less than 95 th percentile for gender, age and height on at least three separate occasions. Hypertension was defined as average SBP or DBP of 95 th percentile or higher for gender, age and height on at least three separate occasions.  Hypertensive study subjects were visited twice within 4 weeks to confirm the hypertension. All those found to be prehypertensive were advised to healthy behavioral changes and asked to check BP regularly at nearest health care facility. Whereas those found to be hypertensive were referred to district hospital and their parents were informed either through telephonic conversation or in person contact.
Anthropometric Measurements: Body weight was measured (to the nearest 0.5 kg) with the subject standing motionless on the bathroom weighing scale.  Each weighing scale was standardized every day with a weight of 50 kg. Height was measured (to the nearest 0.5 cm) with the subject standing in an erect position against a wall and with the head positioned and hence that the top of external auditory meatus was in level with the inferior margin of the bony orbit. Body mass index  (BMI) was calculated as weight in kilograms/(height in meter). 
Student who had BMI for age ≥85 th and <95 th percentile of reference population were classified as overweight. Students who had BMI for age ≥95 th percentile of reference population were classified as obese.  Waist circumference (WC) was measured with a nonstretchable tape at the mid-point of lowest rib cage and the iliac crest, to the nearest 0.1 cm in a standing position during end-tidal expiration. Abdominal obesity as per Indian reference was defined as WC above 75 th percentiles for age and sex. 
The collected data were entered and analyzed using Epi Info 2000 (Center for Disease Control and Prevention, Atlanta, Georgia, USA) SPSS version 16 (SPSS 16.0 for Windows, release 16.0.0. Chicago: SPSS Inc). Frequencies of all variables were taken to check frequencies. Mean and standard deviation (SD) were calculated. Partial coefficient correlation was used for continuous variables. Nomogram was constructed for the population under study for age and sex by using percentiles.
| Results|| |
A total of 958 participants from 83 schools of three randomly chosen PHC were included in the study and data were analyzed for the same. Out of 958 study subjects, 464 (48.4%) were male and 494 (51.6%) were female. Overall mean SBP level was 97.2 mmHg (SD: 15.8) and DBP level was 62.1 mmHg (SD: 11.9). Among Males mean BP level was 97.4 mmHg (SD: 15.3), which was higher than females 96.9 mmHg (SD: 16.3). However, the mean diastolic pressure was 61.4 mmHg (SD: 11.7), which was less than females 62.8 mmHg (SD: 12.2).
In the first visit, out of 958 participants 6.5% (n = 63) were found to be hypertensive and 6.9% (n = 67) were found to be prehypertensives. The 63 hypertensive participants were again visited twice to find out persistent hypertension. On the second visit, the prevalence of hypertension and prehypertension was 3.6% (n = 34) and 8.4% (n = 80) respectively.
Finally on third visit, the prevalence of hypertension and prehypertension was found to be 3.0% (n = 29) and 8.24% (n = 79), respectively. Prevalence of hypertension among males was 2.8% (n = 13) against 3.2% (n = 16) in females. However, the prevalence of prehypertension was observed 8.4% (n = 39) among males when compared to 8.09% (n = 40) in females.
[Table 1] shows the age wise distribution of BP among children from 6 to 16 years. Mean SBP and DBP level found to be increasing from 6 years to 16 years in both the sexes. The mean SBP was higher among males compared with females until 12 years of age. Similarly, this transition was found to be earlier in DBP level, which was seen just after 9 years of age.
|Table 1: Distribution of SBP and DBP according to sex and anthropometric characteristics|
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Overall mean weight and mean height was more in males as compared to females in different age groups. However, BMI was more until the age group of 12 years in males as compared to females after which females had higher in BMI.
Blood pressure nomogram was constructed for the study population in the age group of 6-16 years for males and females. The comprehensive distribution of SBP and DBP of the study participant for age and gender groups has been shown as 3 rd , 5 th , 10 th , 15 th , 25 th , 50 th , 75 th , 90 th , and 95 th percentiles [Table 2] and [Table 3].
[Table 4] shows the correlation of BP with antrthopometric variables with reference to gender. Result revealed that systolic and DBP of both the sexes have positive relationship (P < 0.01) with BMI, height, and WC.
| Discussion|| |
Early identification of hypertension and prehypertension translates into early interventions and possibly prevention of later morbidity and mortality.  In the present study, the prevalence of hypertension found to be 3.0%. It was almost similar to other Indian studies from rural area. Mohan et al.  in his study among children from rural area reported the prevalence of 2.56%. In the present study, the prevalence of hypertension among males was found to be 2.8% and females 3.2%. The difference was not statistically significant (P > 0.05). Similarly, Savitha et al. showed no such sex predilection for hypertension among males and females.  A trend of increase in mean values of SBP and DBP with age in the present sample has been observed in both sexes as shown in [Table 1].
In most of the cross-sectional studies in various populations of the world, an increase of SBP and DBP with age has been reported. , The age related increase in BP may be attributed to the increase in body mass.
The present study shows mean systolic pressure was more in males than females till 12 years of age thereafter females had higher mean systolic pressure than male counterpart of same age. Similar trend was seen in the mean DBP. The differences in patterns of increase in BP between males and females are probably related to certain biological and psychological factors. The appearances of secondary sex characters together with the menarche are associated with a high level of anxiety resulting in higher BP in girls. Similar findings were observed by Durrani et al. suggesting of spurt in BP between 12 and 16 years of age.  This spurt in BP is attributed to certain biological and psychological factors in puberty. ,
Present study showed positive correlation of SBP and DBP with height, weight, BMI and WC which is consistent with the previously reported studies on BP in children.  Whereas Sarin et al. could find correlation of BP with body weight only.  The study of childhood hypertension is paramount importance as BP in childhood is the best predictor of hypertension in later life supported by phenomenon of "tracking."  Studies have documented target organ damage among asymptomatic hypertensive hence healthy behavioral changes among prehypertensives and early diagnosis and treatment can reduce long term morbidity and eventual mortality in later life.
We prepared the BP Nomogram as per age and sex ranging values from 3 rd to 95 th percentile. This shows lower 90 th and 95 th percentile values as compared to NHLBP guidelines. Similar findings were obtained by Jafar et al. in his study while comparing South Asian children body-mass-adjusted BP levels with white children in the United States. 
| Conclusion|| |
Present study identifies the variation in BP level as per age, gender and anthropometric variables. SBP and DBP found to be correlated with the BMI, WC which identifies the need of proper dietary changes at individual and family level. Constructed nomogram for study participants' shows lesser SBP and DBP values for 90 th and 95 th percentiles as compare to NHLBP guidelines. This suggests lesser BP cut off needed to identify maximum hypertensive population among Indian children.
It was school based study and had access to only definite population, but Wardha district school enrolment is quite high hence majority of the study population was covered.
Author recognizes many other documented factors, which could have effect on outcome of the study. Ideally, parental BP should have been taken, but due to study setting it was not accomplished. Dietary history, environmental condition should have been ascertained through household visits. To draw comprehensive reference data for BP among children require further research and larger studies.
| Acknowledgment|| |
I sincerely acknowledge the efforts of staff at Department of Community Medicine, Mahatma Gandhi Institute of Medical Sciences, Sevagram Maharashtra, for their whole heartedly involvement, kind help, support and suggestion for this research work. Author also acknowledges the support provided by the principals of all the schools and also the school children for their participation in the study.
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[Table 1], [Table 2], [Table 3], [Table 4]
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