| Abstract|| |
Hypertension is considered a major health problem in several populations of the world. We compared a few isolated and three comprehensive studies covering the whole Kingdom of Saudi Arabia. The results show that different investigators found different prevalence of hypertension in different areas of the kingdom. There is a need to unify the diagnostic procedures and to determine the factors behind such significant differences.
Keywords: Hypertension, Diabetes mellitus, Obesity, Saudi Arabia.
|How to cite this article:|
El-Hazmi MA, Warsy AS. Hypertension in Saudi Arabia. Saudi J Kidney Dis Transpl 1999;10:365-71
| Introduction|| |
Hypertension is one of mankind's most common diseases and a major health problem affecting as much as 50% of the adult population in some areas of the world. ,, Furthermore, prevalence of hypertension may vary within the same population depending on the ethnic background.,
Hypertension has several associated complications, which cause major morbidity and mortality, such as coronary artery disease, cerebrovascular disease and renal failure.  Control of blood pressure can significantly reduce the risk of strokes, heart disease and renal failure. Efforts should be directed towards early recognition and successful control of hypertension in an attempt to diminish the associated complications. ,,,
It is well documented that industrialization has played a significant role in increasing the presence of hypertension. The World Health Organization (W.H.O.) predicted that the increase in prevalence of hypertension would become a major health problem in the developing countries as they become more industrialized. 
Hypertension is a multifactorial disorder that may be precipitated in genetically susceptible individuals in presence of the right environmental factors. , Twin and adoption studies have shown familial aggregation of hypertension. Relatives of individuals with hypertension have a higher risk of developing hypertension compared to those without hypertension. 
Males have a high susceptibility to develop hypertension during young age.  In both sexes the prevalence of hypertension increases with age and in the black populations the prevalence is higher than the whites.  Among the dietary factors, mineral content seems to significantly influence the prevalence of hypertension. High salt and low potassium intake seem to increase the incidence of hypertension, while reduction in dietary salt intake decreases it. ,,,
Obesity also plays an important role in hypertension. Studies have shown that reduction in body weight results in reduction in blood pressure. ,, Other environmental risk factors include stress, smoking and caffeine intake, which may all help developing hypertension.  Exercise, on the other hand, plays an important role in lowering blood pressure, possibly through its effects on obesity or through other factors. 
| Hypertension in Saudi Arabia|| |
Only a few studies have documented the prevalence of hypertension in Saudi Arabia. One of the earliest reports was from AlMadina Al-Munawarah. The study included 1713 adult Saudis; all in the age range of 5060 years. Hypertension was defined as blood pressure more than 160/95. The results showed that prevalence of hypertension was 10% (6.8% in males and 14.6% in females), whether single or multiple blood pressure measurements were used to assess it. 
Nazimuddin  examined individuals with ages ranging between 18-50 years in the northern province of Saudi Arabia. He reported that if diastolic blood pressure of > 90 mmHg was considered as the cut-off point for definition of hypertension, the prevalence of hypertension would be 15.2%, while if > 95 mmHg was used, the prevalence of hypertension would be 5.25%.
In another report from the Asir region in the southern part of Saudi Arabia, Mahfouz and Al-Erian reported prevalence of 2.4% among Saudi males and females aged 45 years and above. 
In a recent study, Al-Nozha et al  screened 13,700 individuals of both sexes in all age groups. Applying the criteria of W.H.O. of blood pressure > 160/95 mmHg as hypertension, they found prevalence of 9.1% and 8.7% systolic and diastolic hypertension, respectively. Among the adults (> 18 years), 5.3% had systolic hypertension, while 7.9% had diastolic hypertension. The majority (>75%) of those with hypertension were 40 years of age or older. In the age group 40-75 years, females had a higher prevalence (15.7%) of systolic hypertension compared to males (p<0.05), while males had a higher prevalence (8.2%) of diastolic hypertension compared to their female counterparts (6.6%)(p < 0.001).
We conducted comprehensive investigations for blood pressure assessment in 35 areas of Saudi Arabia.  We measured systolic and diastolic blood pressure in 14,660 adult Saudis (6,162 males and 8,498 females) during a study conducted as a component of a national investigation to determine the frequency of diabetes mellitus in Saudis. , The overall prevalence of hypertension was 4.37%, with a slightly higher prevalence in the males (5.39%) compared to the females (3.65%). However, there was a significant variation among the different regions. The highest prevalence was in the males (17.47%) and females (13.03%) of the Eastern province, and the lowest was in the males from Central province (3.68%) and females (2.64%) from South Western Province [Figure - 1]. Furthermore, grouping into areas (cities, towns, and villages) within the region also showed significant variations. No cases of hypertension were seen in Farasan and Mahayel, Al-Kharj and Afeef, but this could be due to the small population groups screened [Figure - 2].
In a more recent study, Al-Nozha and Osman  reported results of a National Nutrition Survey in which blood pressure was checked in 17,892 individuals from age 12 years and above. There were 6260 adults over 18 years of age. The prevalence of systolic and diastolic hypertension was determined by using two cut-off values i.e. > 160/95 and > 140/90. The prevalence of systolic and diastolic hypertension in the adult population was 5.3% and 7.3%, respectively, using the cut-off value of 160/95. There were significant geographical variations. The prevalence of systolic blood pressure was the highest in Taif, Farasan and Hail and lowest in Asir, Jizan and AlMadina. The prevalence of diastolic blood pressure was highest in Al-Qassim, Jeddah, Tabouk and Hail and lowest in Makkah. Interestingly, females generally showed a higher prevalence compared to the male counterparts in all geographical areas. The prevalence of hypertension peaked in the 40-70 years age group and increased significantly compared to the prevalence in the 18-29 years and 30-39 years age group. 
The results of Al-Nozha and Osman  are different in several aspects from the results of other investigators. Khalid et al  in Asir reported a 1.4 % prevalence of hypertension by using blood pressure of 160/95 mmHg as the cut-off value. They reported zero prevalence of hypertension in the inhabitants of areas with low population and found no differences among the different age groups. Comparison of the results of El-Hazmi et al  and Al-Nozha and Osman  showed statistically significant differences in the prevalence of hypertension, where the former study reported much lower prevalence compared to the latter in all areas, [Table - 1]. The very high prevalence in the study of Al-Nozha and Osman is difficult to explain. In Asir, they reported a total prevalence of 17.3%, while others reported a significantly lower prevalence in the same region. ,,
El-Hazmi et al  reported similar prevalence of hypertension in females (3.2%) but lower in males (5.96%) compared to that reported in Al-Madina by Ahmed and Mahmood. 
These differences in the prevalence of hypertension are very difficult to comprehend, unless one explains them based on some bias during sample collection or differences in the method of blood pressure measurement. Bias in sample collection is unlikely as both were large surveys based on household visits by trained health teams.
Soyannwo et al  reported a 1.5 times higher prevalence of hypertension in Qassim compared to that of Al-Nozha and Osman.
Al-Nozha and Osman's study places Saudi Arabia among the countries with high prevalence of hypertension, such as Japan, Korea and China, while most other studies show that Saudi Arabia in fact falls with the low prevalence countries as listed by Page.  A few careful studies need to be carried out in which the blood pressure measurement is made not on one but at least 2-3 occasions in the same person to obtain the exact prevalence of hypertension. The prevalence of hypertension appears to be lower in Saudi population compared to the results reported from studies in other populations such as USA, Britain and France. ,,, In three districts in France, a study reported a 40.2%, 43.8% and 27.7% prevalence of hypertension in males and 31.5%, 33.0% and 18.9% in females, respectively.  The difference in hypertension prevalence within the Saudi population compared to other populations of the world are probably due to differences in genetic make-up, salt intake, degree of stress, obesity and other factors.
Since hypertension is a treatable disease, regular screening programs are required to identify the populations that have the disease in order to treat them at early stages. This strategy, if adopted, should reduce the fearful associated complications. In conclusion, the studies conducted in Saudi Arabia so far reveal that in adult Saudis the prevalence of hypertension varies in different areas and is affected by age and sex. However, different investigators have reported different prevalence rates. More studies are required to settle these differences.
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Mohsen A.F El-Hazmi
Department of Medical Biochemistry, College of Medicine and King Khalid University Hospital, P.O. Box 2925, Riyadh 11461,
[Figure - 1], [Figure - 2]
[Table - 1]