The Prevalence of Hypertension in Different Geographical Regions of Saudi Arabia
From the College of Medicine (Prof. Al-Nozha) and College of Applied Medical Sciences (Dr. Osman), King Saud University, Riyadh, Saudi Arabia.
MM Al-Nozha, AK Osman, The Prevalence of Hypertension in Different Geographical Regions of Saudi Arabia. 1998; 18(5): 401-407
Abstract
Background: The results of the National Nutrition Survey of the people of the Kingdom of Saudi Arabia showed that the prevalence of arterial hypertension (BP≥160/95 mm Hg) among the adult population is 5.3% and 7.3% for systolic and diastolic hypertension, respectively. The objective of this study, which is part of the Survey, was to investigate if the diversified ecological nature of the life of the people of the Kingdom has an effect on the prevalence of arterial hypertension in adult population in the different geographical regions of the Kingdom.
Materials and Methods: The Survey was population-based, employing cluster sampling methods and household visits by health teams trained by the same investigators to avoid individual variations and ensure data validity. 2556 families with 17,892 individuals of all ages were randomly selected from 12 areas according to the population distribution all over the Kingdom. The total number examined for BP with complete data amounted to 13,700 individuals, of whom 6260 were adults (over 18 years of age). The WHO definition of arterial hypertension was used. Also used was the definition of 140/90 mm Hg.
Results: Systolic blood pressure hypertension (SBPH) showed a statistically significant difference (P<0.001) among the regions. The highest prevalence was found in Farasan (8.9%) and the lowest was reported from Asir (2.2%). There was a higher' prevalence among females compared to males in the 40-75-year age group in all regions, except in the highlands of Al Taif and Asir. However, the difference was not statistically significant except in Makkah (25.9%, P<0.001) and Al Sharkia (22%, P<0.03). Diastolic blood pressure hypertension (DBPH) prevalence increased with age in all regions, except in males of Farasan, Makkah, and in females of Asir. The difference in the prevalence between regions was statistically significant (P<0.001). The highest DBPH prevalence (sexes combined) was reported from Al Qassim (10.6%) and the lowest from Makkah (4.2%). Using the definition of hypertension as ≥ 140/90 mm Hg, the highest SBPH prevalence was reported from Makkah (sexes combined) (27.9%), while the lowest was found in Jeddah (14.9%). The highest prevalence of DBPH was reported from Al Taif (36.2%) and the lowest from Makkah and Asir (22% each). The prevalence of SBPH and DBPH was insignificantly higher among females than males in eight and seven of the 12 regions, respectively.
Conclusion: There is a statistically significant difference in the prevalence of SBPH and DBPH in the different regions of the Kingdom (P<0.001). The prevalence pattern tends to be fairly similar to that found in the affluent societies in the Western countries.
Ann Saudi Med 1998;18(5):401-407.
Key words: Hypertension, blood pressure.
Hypertension and other related complications are recognized as emerging clinical and public health problems in Saudi Arabia. Several recent reports have shown an increasing bed occupancy in hospitals from angina, myocardial infarction, nephropathy and stroke.1-4 The emergence in Saudi Arabia of a pattern of chronic diseases similar to that of affluent societies, such as coronary heart diseases, hypertension, stroke, diabetes mellitus and malignant diseases, has caused a lot of concern among health providers and policy makers. Lifestyle and dietary factors have been incriminated worldwide as being contributory factors of some of these diseases. The Kingdom has witnessed dramatic changes in these aspects during the last three decades that followed the economical development in the country.
The results of the National Nutrition Survey, which was carried out during the period 1989-1994, showed that the prevalence of hypertension among the population of the Kingdom, using the WHO definition of hypertension (BP≥160/95 mm Hg),5 is 9.1% and 8.7%, for systolic and diastolic hypertension, respectively.6
A few studies have reported the prevalence of hypertension, mostly in urban areas of the Kingdom, with rates ranging from 2.4% to 15.4%. These differences are due to the selection of target study groups in relation to gender, age, and other criteria used for the definition of hypertension.6-12
The Kingdom of Saudi Arabia has a diverse geographical distribution of inhabitants, ranging from dwellers of inland desert to coastal and mountainous regions, with populations of different ethnic origin and food habits. One of the objectives of this study was to determine the prevalence of hypertension in each of the regions of the Kingdom.
Methods
Materials and Methods
The study is part of a National Nutrition Survey of the people of the Kingdom of Saudi Arabia.13 Cluster sampling technique was used to select the study sample, ensuring representation of rural and urban areas. The sample was estimated to be 17,892 individuals of all ages. Taking the average Saudi family size to be seven individuals, this gives a sample of 2556 families. The families representing the sample were chosen from each of the 12 study regions, according to the percentage distribution of the population all over the Kingdom. The data was collected by health teams who were trained by the same investigators in all regions. Household visits were arranged in advance and people were informed about the objectives of the survey.
The information collected consisted of anthropometric, clinical, biochemical and dietary components. The total number examined for BP with complete data amounted to 13,700 individuals of both sexes among all age groups, of whom 6260 were adults (above 18 years of age).
For adults, a hypertensive case was defined as one with DBP≥95 mm Hg and SBP≥160 mm Hg, or a patient with established hypertension who is receiving medication. The definition of BPH≥140/90 mm Hg was used as well, for ease of comparison with other studies that use this definition.
BP was measured by primary health care physicians who had had prior extensive training. Cross-check quality control procedures were employed to ensure validity of the results all over the country.
In systolic BP measurement, the first Kortokoff phase (Kl) was defined as the appearance of two consecutive beats. For diastolic BP the fifth K5 was defined as the last beat before the disappearance of the sound.
The study subjects were seated and the right arm was laid on the table top. The appropriate cuff size was used. A standard sphygmomanometer was used to determine the pressure necessary to obliterate the radial pulse. BP was measured to the nearest even number. Three BPs were measured with a minimum of 30 seconds' rest between each determination, and values were used for calculation of the mean BP. Chi-squared test was exploited for frequency comparison in this study, using SAS package. P<0.05 was considered statistically significant.
Results
Tables 1 and 2 show the prevalence of systolic BP among the population of the different regions by sex and age. Taif males showed the highest prevalence of systolic hypertension (8.7%), followed by Hail (8.5%), while the lowest prevalence was recorded in Makkah, where males showed no SPB above 160 mm Hg, followed by Farasan and Asir (3.2% each), and Jizan (4.3%).
The highest SBP prevalence among females was reported from Makkah (10.3%), followed by Al-Taif (6.9%) and Tabouk (6.3%). The lowest prevalence was recorded in Asir (1.4%), followed by Al-Madina (3.9%). However, males showed higher prevalence of SBPH than females, yet the difference was not statistically significant, except in Farasan, Makkah and Al Sharkia, where females showed highly significant differences of 50%, 25% and 22%, compared with 6.3%, 0%, and 9.5% in the age group of 40-75 years. The SBP rises significantly with age and the highest prevalence was seen in the 40-75-year age group in all regions. There is a statistically significant difference in SBPH (sexes combined) among the regions (P<0.001). The overall prevalence for all ages showed that the highest prevalence was recorded in Farasan (8.9%), followed by Al-Taif (7.7%), and Hail (7.1%), and the lowest was shown in Asir (2.2%), followed by Jizan (4.4%) and Al-Madina (4.5%).
Tables 3 and 4 show the prevalence of diastolic BP among the populations of the different regions of the Kingdom by age and sex. The highest diastolic BP prevalence (sexes combined) was recorded in Al Qassim (10.6%), followed by Jeddah (10.1%), Tabouk (9.8%) and Al-Taif (9.7%). The difference between the regions was statistically significant (P<0.001). The males of Jeddah showed the highest prevalence (15.6%), followed by Al-Taif (11.9%) and Hail (9.9%), while the lowest prevalence was recorded in Tabouk (3.7%), followed by Jizan (6.2%), and Al-Sharkia and Farasan, which showed a prevalence of 6.6% each. The females of Tabouk showed the highest prevalence (14.9%), followed by Farasan (11.1%) and Al Qassim (9.6%), while the lowest prevalence among the females was reported from Makkah (2%), followed by Al-Madina and Asir (4.8% each). There was a significant increase in DBPH with age in all regions of the Kingdom, except in Farasan, where the prevalence in males decreases with age (6.3% versus 12% in the 40-75-year and 30-37-year age groups, respectively).
If hypertension was defined as ≥ 140/90 mm Hg, the highest prevalence of SBPH (sexes combined) was reported from Makkah (27.9%), Hail (27.1%) and Al-Taif (24.5%), while the lowest was found among the people of Jeddah (14.9%), Jizan (17.0%) and Asir (17.3%) (Tables 5 and 6).
The highest overall prevalence of DBPH was reported from Al-Taif (36.2%), Al-Qassim (34.2%) and Tabouk (28.2%), while the lowest prevalence was found in Makkah (22.0%), Asir (22.0%) and Riyadh (22.1%). The highest prevalence of SBPH and DBPH was found among females of eight and seven regions, respectively, out of twelve, as compared with males among the 40-75-year age groups (Table 5, 6, 7 and 8). However, the difference was not statistically significant except for SBPH of females from Farasan.
Discussion
Hypertension is an important independent risk factor for large vessel disease, frequently resulting in death or disability from myocardial infarction, stroke and peripheral vascular disease. With the improved health services in the Kingdom over the last three decades, the average life expectancy for both sexes has increased from 53.9 years in 1970-75 to 69.2 in 1990-95.14 This increase in life expectancy could lead to the emergence of non-communicable chronic diseases.
There is a statistically significant difference in hypertension prevalence among the different regions of the Kingdom (P<0.001).15 The prevalence of hypertension in the Asir region, as shown by this study, is similar to that reported by Mahfouz and Al-Erian (2.4%).16 In the young age groups (18<29 and 30<39), systolic hypertension (SBP ≥160 mm Hg) is rarely seen among the males, except in Asir, Jizan, Al-Sharkia and Al-Taif. However, the females showed a higher prevalence than males in all regions in the 40-75-year age group, except in the highlands of Al-Taif and Asir.
The difference in SBPH between males and females among all age groups is not significant except in Farasan, Makkah and Al-Sharkia, where females showed higher prevalence (Tables 1 and 2). The results of this study are different from those of Mohsen et al.17 in Egypt, in terms of the younger age group, where it was reported that males were more systolic hypertensive than females, however, similar results are found in the older age group, where females were more systolic hypertensive than males.
In Farasan, Al Madinah, Jizah, Hail and Tabouk, no DBPH was reported among males in the young age group of 18<29 years, while the females of Farasan, Hail and Al-Taif showed no hypertension in this young age group. In the age group of 40-75 years, males were found to have a low prevalence of DBPH in seven out of twelve regions, a result that is different from that of Mohsen et al.,17 who reported a consistently higher prevalence of DBPH in males than females in that age group in Egypt. Ahmed and Mahmoud19 reported that the prevalence of hypertension (160/95 mm Hg) among males and females of 50-60 years in Al Madina is 6.8% and 14.6%, respectively, a result that is lower than what we found for the males, but similar to that of the females (14.3%) in the 40-75-year age group. Wahid et al.7 showed that among adults of Riyadh, the hypertension (≥160/95 mm Hg) prevalence is 15.4%, a figure three times higher than our findings, while Soyannwo et al.10 showed that for 19 year olds and above in Al Qassim, SBPH and DBPH (140/90 mm Hg) prevalence is 1.5 times higher than that reported in our findings for SBPH, but similar to our findings in relation to DBPH.
In the highlands of Asir, Khalid et al.19 reported that the prevalence of hypertension (160/95 mm Hg) was 1.4%, while no hypertension was detected among the lowland inhabitants of 10 to 72 years of age, a result similar to that reported in this study in the female population in the Asir region. However, Mahfouz and Al-Erian16 reported hypertension prevalence among Saudis of 45 years and above in the Asir region to be about 50% less than that of our findings.
The prevalence of hypertension (160/95 mm Hg) in three districts in France20 was found to be 40.2%, 43.8% and 27.7% among males and 31.5%, 33.8% and 18.9% among females, respectively, indicating a higher prevalence than that of this report. However, the pattern is different, as the prevalence in French males is higher than that of the females. The prevalence of DBPH (≥90 mm Hg) in the different regions of the Kingdom (sexes combined) ranges between 22.0% and 36.2%, which tends to be similar to the prevalence of DBPH (32.7%) in Americans.21
In conclusion, this study reveals that in adult Saudis there are differences in the prevalence of hypertension in relation to gender, age and geographical regions. The prevalence increases with age, and it is highest among the 40-75-year age group. The females tend to have insignificantly higher prevalence than males in that age group. The prevalence of SBPH is higher in Taif, Farasan and Hail, and lower in Asir, Jizan and Al Madinah, while the prevalence of DBPH is higher in Al Qassim, Jeddah, Tabouk and Al Taif, and lower in Makkah, compared with other regions of the Kingdom.
The diversified ecological life of the people of the Kingdom has definitely led to the differences in the pattern and degree of the prevalence of diseases. Work is being done now to elucidate the risk factors for hypertension in the Kingdom.
Acknowledgement
The authors would like to thank Mr. Mohammed Salim for typing the manuscript and for secretarial assistance.
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