| Abstract|| |
A prospective study was carried out over a three-year period (1993-95) on 4469 school children drawn from 20 different schools in rural areas of Jordan. There were 2592 males and 1877 females aged between 6-16 years. The height, weight, systolic and diastolic blood pressure (BP) were recorded for both sexes followed by complete clinical examination. The BP was recorded according to the criteria laid down by the second task force on BP in children, using mercury sphygmomanometers, in sitting position and in the right arm. Data were analyzed and the percentiles were calculated for each age-group in both sexes. Both systolic and diastolic BP had positive correlation with age, height, weight and body surface area. There were no differences in the systolic BP for both sexes of corresponding age, while there was a difference in the diastolic. The upper limits of normal, 90th percentile, systolic/diastolic pressures were 116/76, 122/80, 128/81 and 139/86 in children aged 6-8 years, 9-11 years, 12-14, and 15-16 years respectively, with prevalence of 13.35% (n = 596). The lower limits of hypertension, 95th percentile, for systolic/diastolic pressures were 122/81, 126/83, 134/84, and 142/88 mm Hg in each of the same age-groups respectively, with prevalence of 6.85% ( = 306), while for severe hypertension, 99th percentile, for the same age-groups the values were 131/86, 134/87, 145/89 and 154/90 mm Hg respectively, with prevalence of 1.95% (n = 87). The findings in this study were consistent with international data. We emphasize the need for regular check up of BP in our children. Also, further studies are necessary including other areas of Jordan and smaller age-group children.
Keywords: Blood pressure, School children, Jordan
|How to cite this article:|
Switty TA, Shaheen BH, Habashneh MS, Kelani Z, Hazza IA. Blood Pressure Among School Children in Jordan. Saudi J Kidney Dis Transpl 1996;7:283-90
|How to cite this URL:|
Switty TA, Shaheen BH, Habashneh MS, Kelani Z, Hazza IA. Blood Pressure Among School Children in Jordan. Saudi J Kidney Dis Transpl [serial online] 1996 [cited 2020 Dec 5];7:283-90. Available from: https://www.sjkdt.org/text.asp?1996/7/3/283/39491
| Introduction|| |
With the increase in knowledge of blood pressure (BP) control in the adult population proper recording, appropriate evaluation and adequate control of hypertension in children, assume great importance. However, BP, measurement is an often neglected portion of the physical examination of children. Systemic hypertension is recognized more commonly in adults (10-15%) than in children and adolescents , . Until recently, the vast majority of data concerning standards normal BP, hypertension, and mechanisms involved in the development of hypertension, have centered on the adult population. However, during the past 15 years, there has been a surge of interest in the field of systemic hypertension in children and adolescents  .
Because systemic BP gradually increases with age and correlates with weight and height throughout childhood and adolescence, reference standards are necessary for the interpretation of values obtained during physical examination ,,,, . In the adult population, hypertension is usually defined as a BP level that exceeds 145-150/90-95 mm Hg. However, we cannot use a single BP level to diagnose childhood hypertension, since it increases with age until skeletal growth and sexual maturity have occurred , . Thus, it is essential to determine the level of abnormal BP for the pediatric patients. Also, to increase early detection of hypertension, BP measurement should be a part of the periodic physical examination in children , .
A task force was established with specific guidelines for the measurement and evaluation of BP in childhood  . We used the criteria of the second task force to set down the standards for normal blood pressure and hypertension among school children in Jordan.
| Materials and Methods|| |
The study population was drawn from school children in 20 schools in different rural areas of Jordan, as part of humanitarian civic action program which is a joint activity between the Royal Medical Services of Jordan and the United States Army, [Figure - 2]a. Age specific percentiles (5th, 90th, 95th, 99th) of systolic blood pressure measurement during the period 1993-1995. The age, weight, height and systolic and diastolic BP were recorded in 4469 school children aged 6-16 years, of both sexes (males, 2592 and females, 1877). Mercury sphygmomanometers were used to record the blood pressure in sitting position with the right forearm placed horizontally on the table.
After applying the cuff of appropriate width (covering two-thirds of the upper arm), the cuff was gradually inflated to about 20 mm Hg above the point at which the radial pulse disappeared; the pressure was then released slowly at a rate of 2-3 mm Hg per heart beat while listening for the first sound (Korotkoff I) using a stethoscope, the diaphragm of which was placed on the brachial artery. The hearing of the sound indicated systolic BP and disappearance of the sound indicated diastolic BP (Korotkoff V). Three readings were taken, with intervals of 1-2 minutes during which the cuff was completely deflated. The mean of the last two readings was recorded as the BP of the child. Also, all study subjects underwent a complete clinical examination.
A comfortable environment was created at the time of recording the BP to keep the child relaxed, free from fear, anxiety or stress.
Statistical analysis of data were carried out using Excel 5 program in an IBM compatible computer. The mean, mode, standard deviation, the 5th, 90th, 95th and 99th centile data, and data correlation were calculated. Also, Student's t-test and chi-square analysis were performed. The levels of BP were defined according to the second task force on BP control in children. Accordingly, BP was normal when systolic and diastolic pressures were less than the 90th percentile for age and sex; high normal, when pressures were between 90th and 95th percentile for age and sex, and high, when the average systolic and/or diastolic BP was equal to, or greater than, the 95th percentile for age and sex in all three recordings.
Significant hypertension was defined as BP measurements persistently between the 95th and 99th percentile for age and sex, and severe hypertension based upon BP measurements persistently at or above the 99th percentile for age and sex. Children were classified according to their age into four age-groups; 6-8 years, 9-11 years, 12-14 years and 15-16 years.
| Results|| |
The age distribution, height, weight and body surface area of the study group are shown in [Table - 1],[Table - 2]. There was a decrease in the number of girls after age 14 years which is due to a sizable number of girls moving out from school for different social reasons. The systolic BP in boys and girls were not significantly different within each age-group (P = 0.2811) but the diastolic was higher in females (P< 0.001). The height of girls aged 6-13 years was significantly greater (P< 0.001) than that of boys of the same age-group, but it became more in boys after the age of 14 years (P< 0.001).
The weight of girls aged 6-13 years was significantly higher (P< 0.001) than that of boys of the same age-group, except at the age of 10 years and after the age of 14 years when the weight was more in boys [Table - 3]. The body surface area of boys aged 6, 7, 9, 10, 14, 16 was more than that of girls of the same age-groups, while it was more in females in the remaining age-groups [Table - 2]. Through out childhood and adolescence, the systolic and diastolic BP in both girls and boys showed a positive correlation (P < 0.001) with age, height, weight and surface area [Table - 4]a and b. The 5th, 90th, 95th and 99th percentile curves of systolic and diastolic blood pressure for both, sexes are shown in [Figure - 1]a, b and [Figure - 2]a, b.
Both systolic and diastolic pressures showed a rising trend with age in both sexes [Table - 5], [Figure - 3]a, b. The upper limits of normal, 90th percentile, systolic/diastolic pressures were 116/76, 122/80, 128/81 and 139/86 mm Hg in children aged 6-8 years, 9-11 years, 12-14 years and 15-16 years respectively, with a prevalence of 13.35% (n = 596). The lower limits of hypertension, 95th percentile, for systolic/diastolic pressure were 122/81, 126/ 83, 134/84 and 142/88 mm Hg in each agegroup respectively, with a prevalence of 6.85% (n = 306), while for severe hypertension, 99th percentile, for the same age-groups, the values were 131/86, 134/87, 145/ 89 and 154/90 mm Hg respectively, with a prevalence of 1.95% (n = 87) [Table - 6].
| Discussion|| |
School children comprise up to 40-50% of the population of Jordan and screening this large number to establish the normal pattern of distribution of BP among children and to provide specific guidelines for the measurement and evaluation became vital. Although the prevalence of clinical hypertension is far less in children than in adults ,,,, , there is enough evidence to suggest that the roots of essential hypertension extend into childhood ,, . Because of the lack of precise information about the relation of BP and cardiovascular risk in children, such data can be derived from sampling large numbers of children , . The overall prevalence of hypertension in the pediatric population in this study was 6.85% and this is consistent with the findings of Rocchini who reported a prevalence of 0.6-11%  .
The level of "normal" BP varies from population to population ,, and is affected by many factors including cuff bladder size , , time of the day ,, , season of the year  , type of sphygmomanometer  , place of blood pressure measurement  , type and number of observations  , arm position  , order of BP measurement  , fasting and non-fasting state  and whether fourth or fifth diastolic BP is used to characterize this parameter , .
In the present study, the systolic and diastolic BP showed a positive correlation with age, height, weight and surface area [Table - 2],[Table - 3] which is consistent with the findings, reported by several studies on BP in children ,,,,,, . Both boys and girls showed an average increase of systolic BP with age (2 mm Hg per year), which is consistent with the findings of the second task force and Sharma, et al , . The 2 mm Hg per year rate of rise of diastolic BP in this study is higher than that reported by the second task force and Sharma, et al (1 mm Hg per year). This can possibly be explained by the difficulty to obtain Korotkoff 5 diastolic BP in children  .
The difference of height in boys and girls after the age of 13 years is due to growth spurt related to earlier onset of puberty in girls  . We found that tall and obese children have higher BP than short and lean of the same age group and sex, as found in several other studies ,,, . Therefore, the level of a given child's or adolescent's BP must be considered with respect to the individual's body size as well as age  . An important aspect of our study was that, for ' all ages, the BP values tended to be higher in girls than those published by the second task force (1987) [Figure - 4]a,b, [Figure - 5]a,b. Our findings are consistent with the findings by Hohn, et al  , who reported that Asian girls had significantly higher diastolic BP compared with other female ethnic groups.
There are no data in school children to support the vigorous definition of BP as normotensive or hypertensive. Nevertheless, it becomes a matter of practical necessity to have definitions and classifications of hypertension to describe when, and how vigorously, one should diagnose and treat hypertension. All physicians who care for children, should be encouraged to measure BP at least once a year, when the child is well.
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Issa A Hazza
Department of Pediatrics, King Hussein Medical Center, P.O. Box 960955, Amman - 11196
[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6]