High blood pressure (hypertension) is a common health problem and a global public health challenge. Hypertension is a silent, invisible killer that can have few symptoms or warning signs. The American Heart Association1 defines hypertension as a Systolic Blood Pressure (SBP) >140 mm Hg or a Diastolic Blood Pressure (DBP) >90 mm Hg or the taking antihypertensive medication.
Globally, about one billion people have hypertension with two-thirds of cases occurring in developing countries. Hypertension is a major cause of premature death. The burden of hypertension is increasing and it is projected that by 2025 about 1.5 million people annually in the South-East Asia (SEA) Region will be diagnosed with hypertension2.
In Malaysia, the overall prevalence of hypertension in individuals >18 years is 32.7% (95% CI 31.6-33.7), or about 6.2 million persons. Furthermore, by 2020 the prevalence of hypertension in Malaysia is projected to be about 35.8%, with an estimated 7.6 million Malaysians aged 18 years and above having hypertension3. Meanwhile, previous studies conducted with university students in countries such as Egypt4, Uganda5, Ethiopia6 and Kuwait7 showed lower rates of hypertension (26.5, 14, 7.7 and 7%, respectively).
Being overweight or obese is a leading cause of death and disability in both the United States and globally and is expected to increase in coming years. Over weight and obesity is also a major risk factor for many heart-related diseases, including hypertension8. Indeed, the prevalence of hypertension is increased in individuals who have a Body Mass Index (BMI) above 25 kg m2.
Lifestyle factors such as cigarette smoking also contribute to hypertensive effects, mainly by stimulating the sympathetic nervous system. Smoking reduces artery flexibility and increases wave reflection to affect central blood pressure. Thus, hypertensive smokers are more likely to develop severe forms of hypertension, including malignant and renovascular hypertension9.
The aim of this study was to determine the prevalence of hypertension among University students in Shah Alam, Malaysia and its association with nutritional factors.
MATERIALS AND METHODS
A cross-sectional study was conducted among private University students in Shah Alam, Malaysia in 2016. Pregnant women were excluded from the study. Data were collected using relevant equipment for measurement of blood pressure, height, weight and waist circumference and self-administered sets of questionnaires. Blood pressure was measured using an automatic sphygmomanometer (Omron, Japan) after respondents were seated and had been at rest at least for 5 min. Participants who had systolic or diastolic readings of >140 mm Hg and >90 mm Hg, respectively, or were taking antihypertensive medication were classified as having hypertension10.
The weight (kg), height (m), BMI (kg m2) and waist circumference (cm) of participants was measured. The Western Pacific Region BMI Classification was used in this study. Normal BMI is between 18.5 to 22.9. Participants with values below this range were classified as underweight, whereas those between 23 and 27.4 were classified as overweight and those with BMI values >27.5 were classified as obese11. Males and females with waist circumference >90 and >80 cm, respectively, were classified as having an increased risk of co-morbidities11.
The questionnaires consisted of 4 parts:
||Socio demographic questionnaire
||Dietary habits questionnaire
Part A of the questionnaire consisted of demographic information of the students. Questions included age, date of birth, gender, race, department, employment status and for those who were employed how many hours they worked per week. The final question asked the students about their total household income, including their parents income.
Part B consisted of 7 items to assess the dietary habits of the study subjects and was used to measure the frequency of food consumption over the previous 1 week. The food and dietary habit question were developed on the basis of healthy eating habits. Dietary questionnaires were useful for evaluating average intake of population or categorizing the intake of individuals based on their food consumption12. Participants were asked to indicate the frequency of food servings they consumed, how often they ate takeaway food and whether they added salt to the food they ate. The frequency was measured using ratings of "never", followed by "once a week", "2-3 times a week", "more than 3 times a week" and "daily". Every item was given a rating from "0" for unhealthy habit to "4" for healthy habits. The score for each item was added and if the total score was above 13, the participant was considered to have healthy nutritional habits.
Part C was used to evaluate smoking as a lifestyle parameter and hypertension risk factor13. Participants were asked whether they smoked and if they had, how may cigarettes they smoked per day and for how many years. Smoking was defined as current use, at the time of the survey, of cigarettes. An ex-smoker was defined as a person who had stopped smoking for the past 6 months and a non-smoker was a person who never smoked14.
Part D asked whether the participant had previously been diagnosed with hypertension. Those participants who responded "Yes" were asked whether they were prescribed antihypertension medications and whether they had any other chronic diseases.
Approval for this study from the Medical Research Ethics Committee of Management and Science University was obtained prior to initiating the study. Verbal and written consent was obtained from all study participants.
Statistical analysis: All statistical analysis were performed using the Statistical Package for Social Science (SPSS) version 20.0 for windows15. Independent t-test was used for continuous variables (age, family income and waist circumference). Chi-square test was used for categorical data and multivariable analysis was performed using binary logistic regression. The significance level was p<0.05.
Among the 410 study participants, 299 (72.9%) were female and 111 (27.1%) were male. The majority were Malay (291; 71.0%), followed by Indian (90; 22.0%), other (18; 4.4%) and Chinese (11; 2.7%). Among those who completed the questionnaire, 355 (86.6%) were not working and 55 (13.4%) were employed (Table 1).
In terms of hypertension and history of chronic diseases, 41 (10%) participants had high blood pressure and of these 17 had been previously diagnosed and were taking medication (Table 2). A small percentage (14; 3.4%) had other chronic diseases. The majority of participants (175, 42.7%) had normal BMI, whereas 88 (21.5%) and 75 (18.3%) were overweight and obese, respectively. Meanwhile, 72 (17.6%) of participants were underweight. For nutritional habits, over half (257, 62.7%) of the participants had unhealthy habits (Table 3).
Gender and waist circumferences were significantly associated with hypertension (p value <0.001 and 0.015, respectively) whereas smoking and nutritional status had an insignificant association (Table 4).
After performing a logistic regression analysis for factors associated with hypertension, only gender and waist circumference were associated with hypertension with an adjusted odds ratio of 1.0 and 2.8, respectively, indicating that students who had larger waist circumferences had a 2.8-fold greater chance of being hypertensive compared to those who had normal waist circumference (Table 5).
|Table 1:||Socio-demographic characteristics of the respondents
||Hypertension and history of chronic diseases
||Association between nutritional factors, smoking and hypertension among respondents
Mean±SDMean±SD Waist circumferences (cm) 86.17±13.4277.76±10.830.015b* *Level of significance at p<0.05, aChi Square test was performed, bStudents t-test was performed, SD: Standard Deviation
|Table 5:||Factors related to Hypertension using logistic regression analysis
|*Binary logistic regression was performed using Forward LR method, Level of significance at p<0.05, Adj. OR: Adjusted odds ratio|
The main finding of this study is that prevalence of hypertension among the Malaysian University students who participated was 10%. Of these, 17 (4.1%) already knew that they had hypertension, whereas 24 participants only learned through this study that they were hypertensive. This result is consistent with a previous study conducted in Nigeria by Tadesse and Alemu6 who showed that the prevalence of hypertension among college students aged 18 years and above was 7.4%.
In this study, only 5 (29.4%) out of 17 students who were previously diagnosed with hypertension took their prescribed anti-hypertensive medication, whereas the remainder did not take medication despite being aware of their condition. The compliance of taking anti-hypertensive medication can yield good blood pressure control. This is supported by a study on adherence with anti hypertensive monotherapy in 13 managed care organizations conducted by Bramley et al.16, who found that approximately 270 (43%) of high-adherence patients achieved blood pressure control compared with 56 (34%) and 15 (33%) patients with medium- and low-adherence, respectively.
Our study showed an association between waist circumference and hypertension among students. The results reveal that students with high waist circumference (90 cm and above for males, 80 cm and above for females) also developed hypertension, it can be said that high waist circumference is a risk factor for developing hypertension. The result is supported by a study conducted by Tawfeek17 in Baghdad that showed waist circumference for men was positively and significantly correlated with systolic and diastolic blood pressure.
In agreement with earlier studies, results of the present study shows that the prevalence of hypertension is higher among males (19.8%) compared to females (6.4%). Male is the most powerful non-modifiable predictor of pre-hypertension among young Israelis 18, where males are almost 2 times more likely to have pre-hypertension compared to females. This finding can be explained by the protective effect of endogenous estradiol in females which does not exist in male. The mechanism of actions is through the activation of vasodilator pathway activated by the sympathetic nervous system and angiotensin19. In addition, a study among healthy adults conducted by Oladapo et al.20 found that 20.8% of study subjects being diagnosed as hypertensive with a BP of >140/90 mm Hg, 42.3% of the men and 36.8% of the women had a BP of >130/85 mm Hg and could be classified as pre-hypertensive. Thus, our results and those of others showed an association between gender and hypertension.
In term of nutritional status, the prevalence of underweight, normal, overweight and obese are 17.6, 42.7, 21.5 and 18.3%, respectively. The high prevalence of overweight and obese individuals recorded in this study compares well with the reported 35.29% of students who were overweight or obese among students of University Santo Tomas in Chile21 and is similar to another study performed in the United States that reported a 33% prevalence of overweight and obesity among University students22. Similarly, a study conducted in Saudi Arabia also found that 29.8 and 18.6% of students at King Abdul Aziz University, Jeddah were overweight and obese, respectively23.
Our findings synchronized with the result of Zhang et al.24 that described overweight and obesity were strongly associated with pre-hypertension and hypertension among studied students.
This study discovers that the prevalence of hypertension is high among college-aged students in Malaysia and these findings could be useful for health authorities who are designing strategies to address this issue and to develop materials used to promote adoption of a healthy life style. This study will also help to identify critical populations in younger age groups that are at risk for developing hypertension. These results could provide a basis for new theories for the early prevention and treatment of hypertension in young adults.
The prevalence of hypertension among a sample of University students in Malaysia was 10%. Giving the young age of the respondents, this prevalence is considered to be high and indicates that additional effort is needed to promote a healthy lifestyle for University students in Malaysia.