The current study showed a high prevalence (40.8%) of hypertension in this region of Sudan. This result is consistent with the recent findings of one study, which reported that 39.6% of the village inhabitants in Northern Sudan had hypertension [20]. A similar rate (38.2%) of undiagnosed hypertension was reported in rural communities along the Nile River in Northern Sudan [6]. Approximately one-third (35.7%) of 954 individuals in Northern Sudan were found to have hypertension [7]. The high prevalence of hypertension in the different communities may be explained by improved statistics, increased awareness of hypertension [21], an increased prevalence of modern lifestyles that are associated with an increased prevalence of diabetes mellitus and obesity [22], and the widespread use of medication, such as steroids and non-steroidal anti-inflammatory drugs [23]. The prevalence rates of hypertension found in this study were much higher than those (15.9%) recently reported for four states (Khartoum, Gezira, Blue Nile, and Kassala) in Sudan [15]. Interestingly, a much higher prevalence (49.1%) of hypertension was reported among 513 adults in a rural setting in Madagascar [12].
Conversely, a lower rate (28.0%) of hypertension was reported in Tanzania [13] and in a population-based sectional study that enrolled 67,397 participants in Ethiopia (31.9%) [24]. In neighbouring Ethiopia, while a low rate (10.5%) of hypertension was reported in a hospital-based study [8], a prevalence rate of 34.7% for hypertension was reported in the capital, Addis Ababa [10]. In a meta-analysis of 43,025 older adults (> 53 years) in 15 African countries, it was reported that the overall pooled prevalence of hypertension was 57.0% (ranging from 22.3 to 90.0%) [25]. Differences in age, culture, dietary habits, behaviour, race and genetics in the different settings may explain the differences in the prevalence of hypertension in the various populations.
In the current study, an older age was associated with hypertension (adjusted OR = 3.20, 95% CI = 2.28–4.51). This result is consistent with the finding in a previous study, showing a significant association between an increasing age and the prevalence of hypertension in Northern Sudan [6]. A significant association between an increasing age and the prevalence of hypertension was reported in Northern Sudan [7]. Because of our study design (controlled for age), it might not be valid to compare our results (age and hypertension) with the results of the large study that was recently conducted in four states (Khartoum, Gezira, Blue Nile and Kassala) in Sudan [15]. Several studies have shown that an older age is significantly associated with hypertension in neighbouring countries, including Ethiopia [8, 9, 11], Tanzania [13] and Madagascar [12]. Similarly, a recent meta-analysis including 43,025 older adults (> 53 years) in 15 African countries showed that an older age is independently associated with hypertension [25]. The high prevalence of hypertension in elderly patients may be explained by the increased stiffness of the aorta and the other arteries as a result of the ageing process.
Our results showed that obese individuals had a 2.41 times higher risk for hypertension. A significant association between obesity and hypertension has been found in Northern Sudan [7]. Our finding showing an association between obesity and hypertension is consistent with the findings that were recently reported for four states (Khartoum, Gezira, Blue Nile and Kassala) in Sudan [15]. Several previous studies conducted in Africa—e.g., Uganda [14], Ethiopia [8, 10, 11] and Madagascar [12]—have reported significant associations between obesity and hypertension. In a recent meta-analysis of 43,025 adults in 15 African countries, overweight/obesity was shown to be independently associated with hypertension [25]. The association between obesity and hypertension may be explained by the increased plasma endothelin-1 and nitric oxide production and adiposity among obese individuals [26, 27]. Moreover, up to a 63% resolution of hypertension can be achieved by the reduction of one’s body weight [28, 29].
Our results and the results of a recent meta-analysis showed there is no association between an individual’s sex and the presence of hypertension [25]. In the current study, there were no significant associations between hypertension and the marital status, education level, alcohol consumption or smoking habit factors. No significant associations were found between hypertension and the marital status, education level, alcohol consumption or smoking habit factors in Uganda [14]. Previous studies have shown that smoking is associated with hypertension [8]. Interestingly, the rates for both smoking (2.5%) and alcohol consumption (0.33%) were low in our survey. Perhaps the rates of smoking and alcohol consumption were underestimated, as many individuals may not have been willing to reveal these habits.
Limitations
It is worth mentioning that our results should be compared with the results of other studies with caution; the differences in the participant selection method used, size of the study population, and lifestyles and ethnicities of the participants should be considered. This study required only two readings, and the time for which the test administrators needed to visit the households may have affected the selection of the participants. Perhaps the predominance of females (70.3%) in the current study population might be explained by the idea that more males than females were working during the time of the survey, and many females were housewives. Some factors, e.g., physical inactivity [11], dietary factors [10] and high fasting blood glucose levels [9], which have reportedly been associated with hypertension, were not explored in our survey, which should be considered limitations of the study.