Hypertension and its related risk factors: an assessment study among medical students in Iraq

Introduction

Cardiovascular diseases (CVD) and cerebrovascular diseases are among the leading causes of morbidity and mortality worldwide, with hypertension (HTN) emerging as a major determinant in the development of both [1]. A recent comprehensive global assessment estimated that 1.39 billion adults, representing 31.1% of the world’s population, are affected by HTN [2]. Furthermore, HTN is responsible for approximately 9.4 million deaths annually [3].

In Iraq, HTN ranks as the sixth leading cause of mortality¹, with an estimated prevalence of 48% among adults according to the WHO 2023 report². The Seventh Report of the Joint National Committee on Prevention, Detection, Assessment, and Treatment of High Blood Pressure (JNC7) established blood pressure (BP) values ≥140/90 mmHg as the diagnostic threshold for HTN. Additionally, the report introduced the category of prehypertension, defined as systolic BP (SBP) between 120 and 139 mmHg and diastolic BP (DBP) between 80 and 89 mmHg, indicating individuals whose BP is elevated but does not yet meet the criteria for clinical HTN [4].

For consistency with widely used classifications, the present study applies the WHO age categories, defining young adults as individuals aged 18-24 years and adults of early middle age as those aged 25-44 years [5]. Ensuring consistent age definitions is essential, as discrepancies can lead to misclassifications and hinder accurate comparisons across studies. Increases in BP directly elevate the risk of serious complications, such as stroke, heart disease, diabetes mellitus (DM) type II, renal impairment, and premature death [6]. Moreover, an earlier onset of HTN is associated with a higher long-term risk of morbidity and mortality from CVD [7]. Evidence has consistently demonstrated that these adverse outcomes can be substantially reduced by effective BP control [8]. Consequently, early detection and management of HTN are critical for preventing future complications and reducing the overall burden on individuals and healthcare systems [9].

Multiple risk factors, both modifiable and non-modifiable, contribute to an elevated BP. These included age, sex, body weight, physical inactivity, smoking, family history of HTN, serum cholesterol levels, DM, and pre-existing vascular disease [10]. Awareness of these risk factors among healthcare professionals and the general population is essential for motivating targeted interventions aimed at preventing HTN development [11].

Most prior research conducted in Iraq has focused on HTN prevalence among the general adult population, with rates reported at 35.6% in 2016 [12] and rising to 45.82% six years later (p=0.003) [13]. Accordingly, limited data are available regarding the prevalence of HTN and prehypertension among university students. Additional national data indicate that the prevalence of HTN among Iraqi adults has shown an upward trajectory, rising by more than 55%, reflecting a growing public health challenge².

University students represent a particularly vulnerable subgroup, as many experience high academic stress, sedentary study habits, irregular sleep patterns, inadequate physical activity, and unhealthy dietary practices, all of which are recognized as contributors to elevated BP. Additionally, early adulthood is a formative period during which lifestyle behaviors are established, potentially influencing cardiovascular risk across lifespan. Despite these concerns, most prior research in Iraq has focused on adults in the general population, leaving limited data on the prevalence of HTN and prehypertension among university students.

This study aimed to assess the prevalence of HTN and prehypertension among medical students at the University of Basrah, College of Medicine, and identifying the significance of associated risk factors.

Material and methods

Study design and setting

This study was designed as a cross-sectional investigation of undergraduate medical students attending the College of Medicine, Basrah University. Data were collected between January and March 2024. The study population included all students enrolled in the college from the first to the sixth year of the study, for a total of approximately 3732 students.

Sampling and sample size

The study subjects were selected using stratified random sampling, and stratification was performed according to the year of education. Sample size was calculated using the following formula:

where n — Sample size; N — Population size (3732 students); Z — Standard normal variant (1.96 for confidence level of 95%); E — Margin of error (5%); P — Population expected proportion by taking the most probable prevalence of HTN as 50% and permissible error as 5% with 95% confidence interval; the minimum sample size was calculated as n=344 students. As the sampling procedure was multistage, considering the design effect, the sample size was further increased by two times, and the final sample size in the study was fixed at 762 cases.

Data collection method

Five research assistants, all final-year medical students, were recruited for the data collection. The assistants received comprehensive training on standardized data collection procedures. Student participants were approached during their working hours in the college's hallways and classes. Following a brief verbal introduction, the research assistants explained the study objectives and obtained informed consent from each participant.

To calculate or report the response rate, the number of students approached (3732) and the number of students who agreed to participate (762) was calculated using the following formula:

Response Rate = Number of participants who completed the survey / Number of people approached × 100 = 762 / 3732 × 100 = 20.4%;

thus, the response was moderate.

a) Self-administered questionnaire: Participants completed a questionnaire based on the WHO STEPS instrument, which aimed to gather information on their sociodemographic characteristics (age, sex, education level, and body mass index, (BMI) as well as their smoking habits (smoking, passive smoking, electronic cigarette smoking), dietary habits (salt intake, fruits intake, vegetables intake, fast food consumption, energy drink consumption, and tea and caffeinated drinks consumption), lifestyle (days of sport practicing, and sleep hours) [14], as showed in Table 1, medical history (previous history of HTN, DM, and raised cholesterol level), and family history of HTN.

b) BP measurement: BP was recorded twice for each participant, with a minimum 2-minute interval between measurements, using an oscillometric electronic sphygmomanometer (BUa50; Medisana-AG, Neuss, Germany), with the patients in a seated position. In conclusion, the BP status of each participant was determined by calculating the mean of two recorded BP readings.

Results

Table 2 shows the sociodemographic characteristics and lifestyle indicators. Data from 762 medical students were collected and analyzed (mean age — 21.15±1.913 years). Slightly more than half were males, and the participants were distributed relatively evenly across educational years. Most students had a normal BMI. The mean height was 1.69±0.09 m. The majority of the participants were non-smokers. Less than half of the participants engaged in regular sports activities. Most participants consumed what they believed to be the correct amount of salt. A high proportion consumed at least two daily servings of fruits and vegetables, although fast food consumption was common. More than half did not consume energy drinks. Caffeinated drink consumption was very common. Additionally, 7.5% had been previously diagnosed with HTN, 3.1% had DM type II, and 50.8% reported a family history of HTN.

The prevalence of HTN and prehypertension, of these 762 students, 102 (13.4%) were classified as hypertensive and 324 (42.5%) exhibited prehypertension. The remaining 336 (44.1%) students had normal BP readings.

Analysis of sex distribution in relation to BP revealed a statistically significant difference (p<0.05) in prevalence. There was a greater frequency of prehypertension among male participants (228, 55.1%) than among females (96, 27.6%). Similarly, HTN prevalence was slightly higher in men (69, 16.7%) than in women (33, 9.5%). Conversely, the proportion of normotensive individuals was substantially greater among females (219, 62.9%) than among males (117, 28.3%). Figure 1 visually illustrates the distribution of HTN prevalence by sex.

Correlation between BMI and HTN status. The data revealed a statistically significant correlation (p<0.05) between BMI and HTN prevalence. HTN rates were considerably higher among obese participants than among those with normal weight. Similarly, the prevalence of HTN was slightly higher in overweight participants (14.5%) than in normal weight participants (12%). Importantly, no cases of HTN were observed among the underweight participants. Figure 2 illustrates the distribution of HTN across BMI categories.

Data presented in Table 3 details the distribution of study participants across various risk factors known to influence BP, subjects were categorized into two subgroups: those with normal BP and those with elevated BP, encompassing both hypertensive and prehypertensive individuals. It is important to acknowledge that the observed correlations between the analyzed factors and elevated BP may have been inflated. This is because the prehypertensive group, encompassing 42.5% of the sample, was combined with the hypertensive group into a single category labeled "high BP" for analysis.

Several factors were significantly associated with BP status. Participants with a family history of HTN were more likely to have high BP (p=0.001). Similarly, individuals with a personal history of HTN demonstrated a higher prevalence of elevated BP than those without HTN (p=0.005). Smoking was also strongly associated with high BP (p=0.001). Salt intake showed a significant relationship with BP (p<0.001). Adequacy of sleep was also influential: individuals with inadequate sleep showed a higher prevalence of high BP (p=0.02). High consumption of tea or coffee (40-60 cups per week) was associated with a higher proportion of HTN (p=0.01). Fast food intake was also significantly linked to elevated BP, with those consuming it more than 3 times weekly showing higher rates of HTN (p=0.008). In contrast, fruits and vegetables intake, personal history of DM, sports activity levels, and energy drink consumption were not significantly associated with BP status.

The descriptive statistics for SBP and DBP among normotensive, prehypertensive, and hypertensive students. The analysis showed significant differences in SBP and DBP across the three BP categories. Normotensive participants had a mean SBP of 113.13±7.71 mmHg, compared with 129.22±4.511 mmHg among prehypertensive individuals, and 148.09±9.937 mmHg among hypertensive participants. Similarly, mean DBP increased across categories, from 75.21±6.575 mmHg in the normotensive group to 81.84±8.458 mmHg in the prehypertensive group and 96.94±10.557 mmHg in the hypertensive group. The standard deviations indicated greater variability in SBP and DBP among individuals with HTN. Overall, both SBP and DBP values increased progressively and significantly from normotensive to hypertensive status.

Discussion

The findings revealed a HTN prevalence of 13.4%. While limited research exists in Iraq on HTN prevalence among university students, our results were slightly greater than those of the national study conducted by Al-Taha M, et al. [15], who reported a 9.9% HTN prevalence among students of medical colleges in Al-Anbar City. Studies in neighboring regions have shown variations. A study conducted by AlWabel A, et al. [9] at Alqassim Medical College, Saudi Arabia, reported a higher prevalence (14.6%), whereas studies as [16] reported a lower prevalence (8 and 7%, respectively). Notably, a study at Isfahan University of Medical Science [10] reported a significantly greater prevalence (17.5%).

Our study identified a prehypertension prevalence of 42.5% among the students. This prevalence aligns with findings from a university in Kuwait (39.5%) [17] and is slightly greater than those reported in Bahrain (30.7%) [13] and Saudi Arabia (29.2%) [15].

The prevalence of HTN in the Middle Eastern region varies considerably across different populations. This variation likely stems from a combination of biological, demographic, social, and environmental factors unique to each population [18][19]. Additionally, discrepancies in prevalence rates observed across studies might be attributed to sampling methods, study settings, and timeframes of the studies [20][21].

This study identified a concerning trend, among the 102 students who were found to be hypertensive, only 30 (29.4%) reported prior diagnosis and treatment. The remaining 72 students (70.6%) had never undergone a BP screening. This result can be attributed to the limited availability of preventive healthcare resources, which is a well-known challenge in Iraq's healthcare system. In this context, students generally do not undergo thorough health check-ups unless they exhibit noticeable symptoms. The study also revealed a high prevalence of prehypertension (42.5%), which is a significant finding. Prehypertension is a crucial risk factor for the development of HTN and cardiovascular diseases later in life. Early detection allows for lifestyle modifications to potentially lower BP without resorting to medication. Risk factors associated with HTN were sex (male), high BMI, family history of HTN, smoking, dyslipidemia, and excessive salt intake.

The present study identified a significant correlation between sex and BP. A greater proportion of male students (16.7%) were hypertensive as compared with females (9.5%). This trend extended to prehypertension, with a prevalence of 55.1% in males and 27.6% in females. These findings align with those of previous studies on the prevalence of HTN. For instance, El-Agroudy AE, et al. reported comparable sex disparities in Bahrain [16], with HTN prevalence of 13.8% in males and 2.8% in females and AlWabel A, et al. [9] in Saudi Arabia found a prevalence of 18.5% among males and 5.3% among females. While the precise mechanisms underlying this sex differences remain under investigation, some evidence suggests a potential role for androgens in regulating BP variations between the sexes [22].

The data presented in this study suggest a positive correlation between family history of HTN and elevated BP in college students. Among the participants with elevated BP, 56.33% reported a family history of the condition. Conversely, 62% of the students with a family history were found to have elevated BP during the examinations. These findings demonstrate a statistically significant correlation between family history and elevated BP, which is consistent with previous research by Al-Taha M, et al. [15] in Al-Anbar and El-Agroudy AE, et al. [16] in Bahrain. Consequently, screening for family members, especially those with a family history of HTN, is crucial for identifying individuals at increased risk.

This study also identified active smoking as a significant risk factor for HTN. Among 126 students who reported daily smoking, 73.8% exhibited elevated BP during the examinations. This finding aligns with previous research by Al-Taha M, et al. [15] and Moussa M, et al. [24] in Egypt. Furthermore, Abd El-Mohsen AS, et al.³ established a link between smoking and HTN, highlighting their synergistic effect in accelerating atherosclerosis and increasing the risk of coronary complications. However, this observation contrasts with El-Agroudy AE, et al. [16] in Bahrain, who did not find a significant correlation between smoking and HTN in their student population. Interestingly, all 126 daily smokers in this study were males, which may contribute to the observed greater prevalence of HTN among males than among females.

This study observed a low prevalence of DM (3.1%) within the sample, as anticipated in a young population. Notably, 62.5% of those diagnosed with DM had a co-diagnosis of HTN. While the limited number of diabetic cases in our sample precludes definitive conclusions regarding the correlation between DM and HTN, prior research by Al-Majed H, et al. in Kuwait [17] supports a well-established link between these conditions. Smulyan H, et al. [25] proposed a potential mechanism underlying the co-occurrence of DM and HTN. Their study suggests a link between DM and increased arterial stiffness. Notably, arterial stiffness was significantly greater in diabetic subjects than in non-diabetic controls, and this stiffness further intensified with both a longer duration of DM type II and the degree of insulin resistance.

The present study identified a positive correlation between HTN and specific dietary habits, including excessive salt and tea/coffee intake. These findings align with previous research conducted by Moussa M, et al. [24] and Al-Taha M, et al. [15], the discrepancy between the current observations, and those reported by El-Agroudy AE, et al. [16] in Bahrain, who did not find a significant correlation between salt intake and HTN in their cohort.

In contrast to previous research conducted by Moussa M, et al. [24] in Egyptian colleges, this study did not identify a statistically significant correlation between physical activity and the presence of HTN. Consistent with numerous previous studies, this study did not observe a statistically significant correlation between fruits and vegetables intake and HTN. It is worth noting that all research cited in the Discussion section used the same classification and cut-off points for HTN, as provided in the JNC7 report.

This study had several limitations. The cross-sectional design restricts the ability to establish causal relationships between HTN and associated risk factors. The sample was drawn exclusively from medical students at the University of Basrah, which may limit the generalizability of the findings to other universities or the wider young adult population in Iraq. Additionally, several variables were obtained through self-reported questionnaires and may have been subject to recall or social desirability bias. BP was measured during a single visit, which may have led to misclassification due to temporary factors such as stress or white-coat effects. Furthermore, potentially important confounders including dietary sodium intake, caffeine consumption, stress levels, sleep quality, and mental health status were not assessed. The study population consisted mainly of young adults, preventing comparison with older age groups and limiting insight into age-related trends in BP. Since the studied group refers to students of higher education who are medical students, the results cannot be compared to general students and extrapolated to the general public. In Iraq, the minimum age at which students start to enter universities is 18-years-old, this is why the range of young age was 18-25 years.

Conclusion

This study identified the prevalence of HTN and prehypertension among undergraduate medical students, the majority of whom were undiagnosed, and BP levels exhibited a positive correlation with established risk factors, including male sex, elevated BMI, family history of HTN, smoking status, dyslipidemia, and dietary habits (particularly salt intake and caffeinated drinks). These findings highlight the critical need to raise awareness of HTN risk factors among both medical students and the general public. Implementing interventions to promote healthy lifestyles and attenuating these risk factors is crucial for improving public health outcomes as well as lifestyle modification and infrastructure measures. The data cannot be extrapolated to the general public because it is not representative of the general population. Given the predominance of prehypertension among college students with abnormal BP, prioritizing preventative measures and appropriate treatment strategies with no delay is essential. interventions may delay the progression to full HTN, potentially reducing the incidence of cardiovascular and cerebrovascular events later in life. Finally, we propose the incorporation of a BP-screening program into routine university entrance physical examinations. This would serve as a first line of defense in identifying at-risk students and facilitating early intervention.

Ethical approval

This study was approved by the Medical Ethical Committee of the Department of Medicine (no. 449, 2024). The requirement for participant consent was waived by the committee because only the patient files were reviewed.

Отношения и деятельность: все авторы заявляют об отсутствии потенциального конфликта интересов, требующего раскрытия в данной статье.