287 JOURNAL OF SCIENCE, Hue University, N 0 61, 2010 HYPERTENSION PREVALENCE AND RELATED FACTORS IN ELDERLY PEOPLE IN KHANH HOA PROVINCE, VIETNAM Truong Tan Minh, Le Tan Phung et al Khanh Hoa Provincial Health Service SUMMARY Hypertension is one of the major health problems among Elderly People has been investigated by many Vietnam authors. Vietnam Institute of Health Strategy and Policy presented a hypertension percentage of 28,4% among Elderly People of aged 60 years or above in 2006. Based on a systemic randomized sample of Elderly People living in Khanh Hoa Province, hypertension prevalence and related factors have been examined. Using cluster sampling with 30 communes seleted from the total of 137 communes of the Khanh Hoa Province, authors had chosen a sample of 2,170 Elderly People to measure blood pressure and collect other anthropometric indeces (weight, height). Correlation and Logistic regression analysis has been used to examine possitive association between anthropometric factors and hypertension.Mean systolic and mean diastolic blood pressures were statistically different in men and women Elderly People with higher percentage in Men. Mean BMI of Elderly People was 20.26 with slightly higher in Men but no statistically significant (20.40 vs 20.17). Hypertension prevalence in Elderly People of Khanh Hoa Province was 48.1% with higher percentage in Men than Women (52.2% and 45.4%, respectively, p = 0,002). The Raglai minority people who are mostly living in the 2 mountainous districts have a relatively low percentage of hypertension (29.7%). There is an association between hypertension and BMI, especially in Women. The survey showed that the prevalence of hypertension among Elderly People in Khanh Hoa in 2008 was 48.1% (95% CI: 46,0% - 50,2%). There were associations between hypertension prevalence with BMI as well as age using multiple regression model with gender plays the role of interaction in the model. Key words: Hypertension, Elderly People, Body Mass Index, World Health Organization. 1. Introduction Vietnam now has approximately 7 million elderly People, accounting for 10% of the population. The aging problem has been an increasing concern in Vietnam in terms of socio-economic status. In an International workshop on Care for Elderly People held in Hanoi in 2009, experts showed that health care costs for elderly people was 7 times 288 higher than the cost of other adults. Common diseases and health problems in elderly people are hypertension, cardiovascular diseases, endocrinologic disorders, depression, arthritis etc. These affect significantly the life quality of elderly people. Studies in Vietnam as well as in the world showed that hypertension is increasingly becoming a health problem of concern. A multi-center study in Bangladesh and India conducted by the WHO gave a prevalence of hypertension among Elderly at 65%. The prevalence was higher in urban area and showed no significant difference by gender. Nguyen Dang Phai’s study on hypertension prevalence among Elderly People in Hai Duong Province – Vietnam based on a sample of 3,117 Elderly People selected in community, showed that the hypertension prevalence was 28.2% with higher among male (30.3% vs 26.7%). Another survey conducted by the National Institute of Health Strategy and Policy in 7 provinces of Vietnam showed the hypertension prevalence of 28.4%. Khanh Hoa is a Southern-Central Province of Vietnam comprised of 8 districts with a population of approximately 1.2 million. This survey aims at examining hypertension prevalence as well as related factors in Elderly People who are living in Khanh Hoa. 2. Methods The study population was Elderly People (60+ years of age) who lived in Khanh Hoa province at the time of study (from Nov to Dec 2008). A cross-sectional design was used with cluster sampling based on 30 communes selected conveniently from 137 communes in the province. Sample size was determined by the following formula: 2 ) 2 1( 2 )1( d pp zn     In which: n = sample size p = hypertension prevalence, take p = 50%. d = desired precision, select d = 3%. Calculated n = 1,067. Adjusted with design effect (DE=2) and 5% missing subjects, we have the final sample size was 2,240 Elderly People. Data collected was age, gender, ethnicity, systolic and diastolic blood pressure, height and weight. Data were entered by EpiData Software version 3.1, analyzed by Stata version 10.0. 3. Results and discussion 3.1. Baseline data There were a total of 2,170 Elderly People seleted for the sample because of 289 some missing and some under 60 years old. Over 60% of the sample was female, reflecting a larger proportion of females amongst the Elderly population. More than 80% of them were under the age of 80. The age group between 80 and 89 had a proportion of 17%. Raglai Ethnic minority People accounted for 3% of the Elderly population (Table 1) Table 1. Baseline Characteristics of the Sample of Elderly People Items Frequent (n=2,170) Percent % Gender: Male Female 849 1,321 39.1 60.9 Age groups: From 60-69 years old From 70-79 years old From 80-89 years old From 90-99 years old >=100 years old 885 866 367 50 2 40.8 39.9 16.9 2.3 0.1 Ethnicity: Kinh Raglai T’rin Others 2,095 64 1 10 96.5 2.9 0.1 0.5 3.2. Anthropometric characteristics of Elderly People 3.2.1. Weight The mean weight of the sample was 49 kg ± 8.7 kg. The mean weight of males was significantly higher than females (Table 2). Table 2. Mean weight of Elderly People by gender Gender Mean weight SD Test Male (n = 849) 52.4 kg 8.5 kg t 2168 = 15.025 p = 0.000… Female (n = 1,321) 46.9 kg 8.2 kg 290 Total (n = 2,170) 49.0 kg 8.7 kg 3.2.2. Height The mean height of the sample was 155cm ± 7.3cm with a statistically higher mean among elderly males (160 cm vs 152 cm). Table 3. Mean height of Elderly People by gender Gender Mean height SD Test Male (n = 849) 160 cm 6.4 cm t 2168 = 28.622 p = 0.000… Female (n = 1,321) 152 cm 6.1 cm Total (n = 2,170) 155 cm 7.3 cm 3.2.3. Body Mass Index (BMI). The mean BMI of the sample was 20.26 kg/m 2 . There was no significant difference in mean BMI between men and women (Table 4). Table 4. Mean BMI of Elderly People by gender Gender Mean BMI SD Test Male (n = 849) 20.40 3.01 t 2168 = 1.683 p = 0.0926 Female (n = 1.321) 20.17 3.14 Total (n = 2.170) 20.26 3.09 According to the WHO classification of BMI (with 4 categories: underweight, normal, overweight, and obesity), this survey showed a percentage of 30% underweight, whereas normal BMI was 64%. The very small proportion of overweight (5.6%) and obesity (0.3%) reflects that overweight and obesity are not a health problem among Elderly People in Khanh Hoa province (Table 5). Table 5. BMI classification of Elderly People by gender Category Male Female Total Test Underweight 239 (28.2%) 409 (31.0%) 648 (29.9%) χ 2 = 2.7525 p = 0.431 Normal 562 (66.2%) 832 (63.0%) 1,394 (64.2%) Overweight 45 (5.3%) 77 (5.8%) 122 (5.6%) 291 Obesity 3 (0.3%) 3 (0.2%) 6 (0.3%) Total 849 1,321 2,170 3.3. Hypertension prevalence. 3.3.1. Mean systolic and diastolic blood pressures. Mean blood pressures, both systolic and diastolic pressure were significantly different between men and women. Men had higher mean blood pressures than women (p<0.001). Table 6. Mean blood pressures by Gender Gender Total Mean BP SD Test Systolic blood pressure (mmHg) Male 849 138 20.6 t 2166 = 3.313 p = 0.0009 Female 1,319 135 20.9 Total 2,168 136 20.8 Diastolic blood pressure (mmHg) Male 849 82 9.9 t 2166 = 3.989 p = 0.0001 Female 1,319 80 10.7 Total 2,168 81 10.4 3.3.2. Hypertension prevalence. Based on definitions and classification of Blood Pressure Levels by WHO/ISH [5], the prevalence of hypertension among Elderly People in Khanh Hoa province was 48.1% that is significantly higher than Nguyen Dang Phai’s and Dam Viet Cuong’s surveys. Hypertension among men was statistically higher than that among women: 52.2% vs 45.4% (Table 7). Comparing hypertension prevalence among Kinh People and Raglai People, who are the main ethnic minority group living in Khanh Hoa Province (most of them are in Khanh Son and Khanh Vinh district), the survey showed a higher hypertension prevalence among Kinh People, probably related to urbanization and sedentary lifestyle in Kinh Pepole. 292 Table 7. Hypertension by Gender and Ethnicity Gender Total Hypertension Percent Test Gender 849 443 22.5 χ 2 =9.46 p = 0.002 1,321 600 45.4 2,170 1,043 48.1 Ethnicity 2,095 1,016 48.5 χ 2 =8.8 p = 0.003 64 19 29.7 3.4. Associations between blood pressure and anthropometric index. Drawing scatter plots by using Stata software showed positive association between systolic blood pressure and BMI and age. Systolic blood pressure has increasing tendency in proportion of BMI to age. Figure 1 and Figure 2 showed those associations. 100 150 200 250 sysBP 60 70 80 90 100 age sysBP Fitted values Figure 1. Association between systolic blood pressure and age 293 100 150 200 250 sysBP 10.00 15.00 20.00 25.00 30.00 35.00 bmi sysBP Fitted values Figure 2. Association between systolic blood pressure and BMI Analyzing associations by gender showed a stronger association in females than males in terms of systolic blood pressure and BMI as shown in Figure 4 and a stronger association in males than females in terms of systolic blood pressure and age as shown in Figure 3. 100 150 200 250 60 70 80 90 100 60 70 80 90 100 female male sysBP Fitted values sysBP age Graphs by gender Figure 3. Association between systolic blood pressure and age by Gender 294 100 150 200 250 10.00 20.00 30.00 40.0010.00 20.00 30.00 40.00 female male sysBP Fitted values sysBP bmi Graphs by gender Figure 4. Association between systolic blood pressure and BMI by Gender Using multiple logistic regression, the model is showed below. However, this model is weak (R 2 = 0.0329) log(sysBP) = 4.5391 + 0.0034*age – 0.0017*gender*age + 0.0051*log(BMI)*gender where: sysBP is systolic blood pressure, gender = 1 if gender is female and = 0 if gender is male. 4. Conclusion 4.1. The hypertension prevalence among Elderly People of Khanh Hoa Province is 48.1% (95% CI: 46.0% - 50.2%). 4.2. Hypertension is higher in elderly males than females (52.2% vs 45.4%), and higher in Kinh People than Raglai People (48.5% vs 29.7%). Both differences are statistically significant. 4.3. There are positive associations between systolic blood pressure and age, and BMI. Gender plays as an interaction role in the multiple logistic regression model. 295 REFERENCES 1. The Communist Party of Vietnam (CPV) Online Newspaper. International workshop on Care for Elderly People on the web at http://www.cpv.org.vn/cpv/Modules/News/NewsDetail.aspx?co_id=30085&cn_id=3720 58, dated 20/11/2009. 2. WHO - Hypertension Study Group. Prevalence, Awareness, treatment and Control of Hypertension among the Elderly in Bangladesh and India: A multicentre study. Bulletin of the WHO, Vol 79 No 6, 2001. 3. Nguyễn Đăng Phải. Survey on hypertension and building a model of caring for Elderly People based on Community. Report to the provincial committee of Hai Duong, on the web http://www.haiduongdost.gov.vn dated 30/11/2009. 4. Dam Viet Cuong et al. Examine Caring for Elderly People in Vietnam – summary report of the year 2006 on the web at http://www.hspi.org.vn/ 30/11/2009. 5. WHO/ISH writing group. 2003 World Health organization (WHO)/International Society of Hypertension (ISH) statement on management of hypertension. “Journal of Hypertension” Vol 21, No 11. 2003. . Analyzing associations by gender showed a stronger association in females than males in terms of systolic blood pressure and BMI as shown in Figure 4 and a stronger association in males than females. Common diseases and health problems in elderly people are hypertension, cardiovascular diseases, endocrinologic disorders, depression, arthritis etc. These affect significantly the life quality