PREVALENCE OF YOUNG ADULT HYPERTENSION IN MALAYSIA AND ITS ASSOCIATED FACTORS: FINDINGS FROM NATIONAL HEALTH AND MORBIDITY SURVEY 2011

Transcription

1 ORIGINAL ARTICLE PREVALENCE OF YOUNG ADULT HYPERTENSION IN MALAYSIA AND ITS ASSOCIATED FACTORS: FINDINGS FROM NATIONAL HEALTH AND MORBIDITY SURVEY 2011 Mohd Azahadi Omar 1, Nining Irfanita Irfan 2, Khoo Yi Yi 1, Norliza Muksan 3, Nur Liana Abdul Majid 4, Muhammad Fadhli Mohd Yusoff 4 1 Centre for Burden of Disease Research, Institute for Public Health, Jalan Bangsar, Kuala Lumpur, Malaysia. 2 Bachelor of Biomedical Science, Faculty of Health and Life Sciences, Management and Science University, University Drive, Off Persiaran Olahraga, Section 13, Shah Alam, Selangor Darul Ehsan. Malaysia 3 Klinik Kesihatan Rasa, Rasa, Hulu Selangor, Selangor, Malaysia. 4 Centre for Non-Communicable Diseases Research, Institute for Public Health, Jalan Bangsar, Kuala Lumpur, Malaysia. ABSTRACT Hypertension is a chronic medical condition and a global public health issue. According to Malaysia's National Health and Morbidity Survey (NHMS) 2006, the prevalence of hypertension among adults aged 18 years and above was 32.2% and had increased slightly in 2011 to 32.7%. However, not much study was done on the prevalence of young adult hypertension in Malaysia. Hence, the aim of this study was to determine this prevalence as well as its associated factors. Data was obtained from the NHMS 2011 study, which utilized a two stage stratified sampling design to conduct a nationwide household survey involving 28,650 individuals. Systolic and diastolic blood pressures, height, weight and blood glucose levels were measured. Binary logistic regression was used to investigate the relationship between prevalence of hypertension and its associated factors. The prevalence of young adult hypertension was 17.3%. After adjusting for other confounding variables, significant association were found in gender [aor : 1.72 (95% CI : )], age [aor : 1.08 ( )], ethnic groups (Other Bumiputera vs Malays [aor : 1.55 ( )], obesity (aor %CI ) and diabetic status [aor : 1.75 (95%CI )]. Early screening, detection and treatment of hypertension among the high risk young adults group is recommended to reduce the long-term risk of complications. Keywords: Young Adult Hypertension, National Survey, Malaysia INTRODUCTION Hypertension is a global public health issue. It contributes to the burden of heart disease, stroke, kidney failure, premature mortality and disability 1. Globally, in 2008, hypertension is affecting almost 40% of adult aged more than 25 years old and the number of people with the condition is approximately 1 billion 2. It is estimated that the number will increase to 1.56 billion adults by The prevalence of hypertension had been reported in various regions of the world 4-6. In Malaysia, according to the National Health and Morbidity Survey (NHMS) 2006, the prevalence of hypertension among adults aged 18 years and above was 32.2% 7 and it rose slightly in 2011 to 32.7% 8. The increasing prevalence of hypertension is attributed to various behavioral risk factors such as unhealthy diet, smoking, harmful use of alcohol, inadequate physical activity and exposure to persistent stress 1. The risk also increased among those with other co-morbidities such as diabetes mellitus, obesity and hypercholesterolemia 1. Generally, young adults are inclined to enjoy good health thus reducing their participation within the healthcare system. Hence, there is a gap in the research of the young adult population, especially with regards to hypertension. Evidence has indicated that the earlier the onset of hypertension, the longer its duration, and the greater the risk for future cardiovascular events 9. It has also been hypothesized that the continuous existence of hypertension risk factors when young may be precursors to the development of essential hypertension later 10. Exposure to long-term periods of raised blood pressure affects measures of cardiovascular function such as left ventricular hypertrophy, increased left ventricular mass and degree of carotid stenosis, which tend to remain at abnormal levels despite pharmacological treatment thus strengthening the hypothesis that the continuous existence of hypertension risk factors when young may be precursors to the development of incipient left ventricular systolic and diastolic function in middle age 10,14. As most studies describe hypertension in older adults and the elderly, there is still lack of data on hypertension in young adults since they are believed to be at lower risk of developing the disease. However, a study conducted in United States found that nearly 1 in 5 young adults (19%) have high blood pressure and hence this inadvertently leads to an increased risk of cardiovascular disease 15. In Malaysia, not much information was available regarding the

2 prevalence of young adult hypertension. Therefore, the study was aimed to determine the prevalence of hypertension and factors associated among young adults aged between 18 years old and 39 years old in Malaysia. METHODOLOGY The data from NHMS 2011 was used and data on hypertension among young adults in Malaysia was further analyzed. Details methodology of the survey was described elsewhere 16.The NHMS 2011 was a household survey conducted by the Institute for Public Health, Ministry of Health Malaysia in the year A two stage stratified sampling design was used. A total of 794 Enumeration Blocks (EB) were selected from the total EBs in Malaysia, where 484 and 310 EBs were randomly selected from urban and rural area respectively. Twelve living quarters (LQ) were randomly selected from each selected EB and all households within the selected LQs and all members in the households were surveyed. The questionnaire was administered only after the written informed consent forms were signed by the participants. A total of 7,522 LQs were successfully visited and 28,650 individuals were interviewed. Systolic and diastolic blood pressures were measured using Omron Digital Automatic Blood Pressure Monitor Model HEM-907. Two readings were taken for both diastolic and systolic blood pressure, with a gap of 15 minutes. The average was used as recorded blood pressure values. Respondents were considered hypertensive if their average reading was 140 mmhg for systolic and/or 90 mmhg for diastolic blood pressure, or were on blood pressure lowering drugs, or were self-reported to be hypertensive. The respondent s height was measured in centimetres using Seca 206 Bodymeter. Weight was measured in kilograms using a digital weighing machine (TANITA HD-319). Body Mass Index (BMI) was calculated using weight and height of the respondents. Respondents with BMI of 30.0 kg/m 2 or more were classified as obese. Blood glucose level was examined for non-diabetic adult respondents after an overnight fasting via finger prick method using Cardiocheck machine. Respondents were considered diabetic if their fasting capillary blood glucose was 6.1 mmol/l or more, or were self-reported to be diabetes. Data was analyzed by using SPSS Version 20. Categorical variables were presented as frequencies and percentages. Pearson s chisquare test was used in order to determine the association between categorical variables. Binary logistic regression was used to investigate the relationship between prevalence of hypertension and associated factors. Results of logistic regression were expressed as odds ratio and 95% Confidence Interval (CI). A two sided p value less than 0.05 was considered as statistically significant. RESULT Total number of respondents in the study was 8,678. Females were slightly higher compared to males (52.4% vs 47.6%). Sixty percent of respondents were from urban area. Majority of the respondents were Malays (58.8%) followed by Chinese (14.6%). More than 85% of respondents had secondary or tertiary education. Almost 55% of respondents were married and more than 70% were working (Table 1). The prevalence of young adult hypertension in the study was 17.3%. There were significance differences by gender, age, ethnic group, educational level, marital status, working status, obesity status and hypertensive status. However, the differences were not significant in residence and smoking status (Table 2) Multivariate analysis (ie : logistic regression) were performed for significant variables in univariate analyses (Table 2). Table 3 shows the adjusted Odd Ratio (aor) of the associated factors for young adult hypertension. The significant associated factors were found in gender, age, ethnic groups (Indians vs Malays, Other Bumiputeras vs Malays), obesity and diabetic status. There were no significant associations between educational level, marital status and occupation status with young adult hypertension. DISCUSSION Young adult hypertension is defined as hypertension diagnosed in individuals less than 40 years old 17. This study showed that the prevalence of young adult hypertension in Malaysia was 17.3% and it was comparable to a study conducted in Indonesia (17.1%) 18. However, the finding was higher as compared to study conducted in India among young female adults of Amritsar and study carried out among respondent aged between 20 and 40 years old of China which prevalent at 12% 19 and 13% 20 respectively.

3 Table 1: Sociodemographic characteristics of the respondents Variable N % Gender Male Female Age Group Residence Rural Urban Ethnic group Malays Chinese Indians Other Bumiputeras Others Educational Level No Formal Education Primary Education Secondary Education Tertiary Education Marital Status Single Married Widow/widower/divorcee Occupation Status Working Not working Smoking Status Non-smoker Smoker Obesity Non-obese Obese Diabetic Status Non Diabetes mellitus Diabetes mellitus The prevalence of young adult hypertension by gender was significantly different. Males showed higher prevalence compared to females. This finding was in concordance with other studies among adults conducted in central region of Nepal 21 and China 20. Similarly, a study conducted in Malaysia among adults showed males have more risk suffering from hypertension compared to females 22. The risk of developing hypertension also increased with age. This finding was supported by other studies 21, The wall of large conduit arteries, especially aorta, thicken and lose elasticity over time, and this process results in an increase in pulse wave velocity, an important and reliable measure of arterial stiffness. The increased arterial stiffness, whatever its underlying cause, would reduce the reservoir/buffering function of the conduit arteries near the heart and increase pulse wave velocity, both of which increase systolic and pulse pressure 25.

4 Table 2 : Prevalence of Young Adult Hypertension and Associated Factors Variables Hypertensive Non-hypertensive χ2 (df) p value n % n % National (Overall prevalence) Gender : Male Female (1) <0.001 Age 30.6 (6.02) # 27.6 (6.15) # <0.001 Residence : Urban Rural Ethnic group : Malays Chinese Indians Other Bumiputeras Others Educational Level : No Formal Education Primary Education Secondary Education Tertiary Education Marital Status : Single Married Widow/divorcee Occupation status : Working Not working Smoking status : Non-smoker Smoker Obesity : Non-obese Obese Diabetic status : Diabetes Mellitus Non Diabetes Mellitus # Mean (standard deviation) *t-statistic (df) using independent t-test (8610)* 3.28 (1) (4) < (3) < (2) < (1) < (1) (1) < (1) <0.001 With regards to ethinicity, the prevalence of hypertension was higher in other Bumiputeras compared to other ethnicities found in Malaysia such as Malays, Chinese, and Indians. Other Bumiputeras were 1.55 times more likely to have hypertension compared to Malays. The disparity may be due to the difference in genetic or socioenvironmental factors 22. Obesity has been known to be one of the most significant risk factors of developing hypertension In this study, the risk of developing hypertension was significantly higher among obese respondents at 4.43 times as compared to non-obese respondents. This finding concurred with a study conducted among young adults in Singapore 28. There are several mechanisms that led to developing hypertension among obese individuals. These mechanisms include increased activity of sympathetic nervous system and impaired endothelial function 29. In addition, environmental, physiologic, and genetic factors may also influence the relationship between obesity and hypertension 29. The prevalence of young adult hypertension was also high among diabetic respondent and they were 1.75 times more likely to have hypertension as compared to those non diabetic respondents. Few studies also reported an association between hypertension and diabetes mellitus Several factors that may lead to hypertension in diabetic patient were insulin resistance/hyperinsulinemia which leads to increased fluid volume and increased arterial stiffness 32. There was no association between smoking and young adult hypertension. Few other studies in Singapore, Saudi Arabia and Uganda also found similar results 28,30,33.

5 Table 3: Factors associated with Young Adult Hypertension (using Logistic Regression) Variable Gender Female Male OR (95% CI) p value 1.49 (1.33,1.67) <0.001* aor (95% CI) p value 1.72 (1.52,1.96) <0.001* Age 1.08 (1.07,1.09) <0.001* 1.08 (1.07,1.09) <0.001* Ethnic group Malays Chinese Indians Other Bumiputeras 0.83 (0.70,0.98) 0.86 (0.68,1.07) 1.30 (1.09,1.54) 0.85 (0.69,1.05) 0.029* * 0.90 (0.75,1.09) 0.68 (0.52,0.87) 1.55 (1.27,1.88) 0.95 (0.74,1.22) * <0.001* Others Educational Level No Formal Education Primary Education Secondary Education Tertiary Education 1.22 (0.78,1.90) 1.04 (0.68,1.59) 0.80 (0.52,1.22) (0.77,2.05) 1.15 (0.71,1.85) 0.97 (0.59,1.58) Marital Status Single Married Widow/divorcee 1.65 (1.47,1.85) 1.84 (1.16,2.92) <0.001* (0.73,1.07) 0.97 (0.57,1.64) Occupation status Not working Working Obesity Non-obese Obese Diabetic status Non Diabetes Mellitus Diabetes Mellitus 1.31 (1.15,1.48) <0.001* 4.39 (3.84,5.02) <0.001* 2.57 (2.15,3.07) <0.001* 1.04 (0.89,1.22) (3.83,5.12) <0.001* 1.75 (1.43,2.15) <0.001* Our findings must be considered within the context of the investigation s limitations. Since data was extracted from the NHMS, there was limited exploration on the possible associations with other risk factors for young adult hypertension such as genetic factor, family history, and dietary salt intake. CONCLUSION Although the prevalence of hypertension was relatively low among young adults, it still constitutes a major health problem since the damage and complications are related with duration of the illness. Given the apt description of hypertension as a silent killer, opportunistic screening and awareness are the key first steps to improving management and prevention, especially in males, those in the younger age group and among the 'other Bumiputeras' ethnic group. Furthermore, there is an urgent need to address modifiable risk factors associated with the development and maintenance of raised blood pressure such as obesity and diabetes at an early age before they start to manifest. ACKNOWLEDGEMENT Authors would like to thank Director General of Health, Malaysia for permission to publish this paper. We also thank those who were involved in the study for their contribution and commitment.

6 REFERENCES 1. World Health Organization. A global brief on hypertension, World Health Organization. Global status report on non-communicable disease 2010, Kearney PM, Whelton M, Reynolds K et al. Global burden of hypertension : analysis of worldwide data. Lancet 2005; 365: Wolf-Maier K, Cooper RS, Banegas J et al. Hypertension prevalence and blood pressure levels in 6 European countries, Canada and the United States. JAMA 2014; 289(18): Neupane D, McLachlan CS, Sharma R, et al. Prevalence of hypertension in member countries of South Asian Association for Regional Cooperation (SAARC) : Systematic Review and Meta-Analysis. Medicine 2014; 93(13): Krishnan A, Garg R, Kahandaliyanage A. Hypertension in the South-East Asia Region: an overview. In World Health Organization South East Asia Region. Special Issue on Blood Pressure take control, Institute for Public Health. The Third National Health and Morbidity Survey (NHMS III) 2006, Institute for Public Health. National Health and Morbidity Survey 2011 (NHMS 2011): Non-Communicable Disease, Buck C, Baker P, Bass M, et al. The prognosis of hypertension according to age at onset. Hypertension 1987; 9(2): Chobanian AV, Bakris GL, Black HR, et al. Seventh Report of the Joint National Committee on prevention, detection, evaluation, and treatment of high blood pressure. Hypertension 2003; 42(6): Wolf PA, D'Agostino RB, Belanger AJ, et al. Probability of stroke: a risk profile from the Framingham Study. Stroke 1991; 22(3): Bikkina M, Levy D, Evans JC, et al. Left ventricular mass and risk of stroke in an elderly cohort. The Framingham Heart Study. JAMA 1994; 272(1): Wilson PW, Hoeg JM, D'Agostino RB, et al. Cumulative effects of high cholesterol levels, high blood pressure, and cigarette smoking on carotid stenosis. The New England Journal of Medicine 1997; 337(8): Kishi S, Teixido-Tura G, Ning H, et al. Cumulative blood pressure in early adulthood and cardiac dysfunction in middle age: The CARDIA Study. Journal of the American College of Cardiology 2015; 65(25): Nguyen QC, Tabor JW, Entzel PP, et al. Discordance in national estimates of hypertension among young adults. Epidemiology 2011; 22(4): Fadhli Y, Azahadi O, Noor Ani A, et al. Approaches in methodology of a population-based study in Malaysia : The National Health and Morbidity Survey 2011 (NHMS 2011). Malaysian Journal of Medicine and Health Sciences 2013; 9(2): Norlela S. Clinical approach to young hypertension. Brunei Int Med J 2013; 9(2): Widjaja FF, Santono LA, Barus NRV et al. Prehypertension and hypertension among young Indonesian adults at a primary health care in a rural area. Med J Indones 2013; 22(1): Rana B & Sidhu S. Relationship of percent body fat (estimated by bioelectrical impedance analysis) with blood pressure among young adult females of Amritsar (Punjab). Human Biology Review 2012; 1(4): Gao Y, Chen G, Tian H, et al. Prevalence of hypertension in China : A crosssectional study. Plos One 2013; 8(6): e Chataut J, Adhikari RK, Sinha NP. Prevalence and risk factors for hypertension in adults living in central development region of Nepal. Kathmandu University Medical Journal 2011; 9(1): Rampal L, Rampal S, Azhar MZ, et al. Prevalence, awareness, treatment and control of hypertension in Malaysia : A national study of 16,440 subjects. Public Health 2008; 122: Bani IA. prevalence and related risk factors of essential hypertension in Jazan

7 region. Saudi Arabia. Sudanese Journal of Public Health 2011; 6(2): Dogan N, Toprak D, Demir S. Hypertension prevalence and risk factors among adult population in Afyonkarahisar region : A Cross-sectional Research. Anadolu Kardiyol Derg 2012; 12: Sun, Z. Aging, arterial stiffness, and hypertension. Hypertension 2015; 65: Lee SH, Kim YS, Sunwoo S, et al. A retrospective cohort study on obesity and hypertension risk among Korean adults. J Korean Med Sci 2005; 20: Hu G, Barengo NC, Tuomilehto J, et al. Relationship of physical activity and body mass index to the risk of hypertension : a prospective study in Finland. Hypertension 2004; 43: Gan SKE, Loh CY, Seet B. Hypertension in young adults an under-estimated problem. Singapore Med J 2003; 44(9): Kotchen TA. Obesity-related hypertension : epidemiology, pathophysiology and clinical management. American Journal of Hypertension 2010; 23(11): Al-Hamdan N, Saeed A, Kutbi A et al. Characteristics, risk factor and treatment practices of known adult hypertensive patients in Saudi Arabia. International Journal of Hypertension 2010; (doi: /2010/168739). 31. El-Bcheraoui C, Memish ZA, Tuffaha M, et al. Hypertension and its associated risk factors in the Kingdom of Saudi Arabia, 2013 : A National Survey. International Journal of Hypertension 2014; (doi: /2014/564679). 32. Cheung MY & Li Chao. Diabetes and hypertension : is there a common metabolic pathway? Curr Atheroscler Rep 2012; 14: Kayima J, Nanbabirwa J, Sinabulya I, et al. Determinants of hypertension in a young adult Ugandan population in epidemiological transition the MEPI-CVD survey. BMC Public Health 2015; 15: 830 (doi: /s y).