HYPERTENSION PREVALENCE AND RELATED FACTORSIN ELDERLY PEOPLE IN KHANH HOA PROVINCE, VIETNAMTruong Tan Minh, Le Tan Phung et alKhanh Hoa Provincial Health Service

1. Introduction

Vietnam now has approximately 7 million Elderly People, accounting for 10% of population. The aging problem has been increasingly concerned 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 cost for Elderly People was 7 times higher than other adult cost [1]. Common diseases and health problems in Elderly People are hypertension, cardiovascular diseases, endocrinologic disorders, depression, arthritis etc. These affect significantly life quality of Elderly People.

Studies in Vietnam as well as over the world showed that hypertension is increasingly concerned health problems. A multi-center study in Bangladesh and India conducted by WHO gave a prevalence of hypertension among Elderly at 65% [2]. The prevalence was higher in urban area and showed no significant difference by gender.

1. Introduction (cont)

On hypertension prevalence among Elderly People in Hai Duong Province – Vietnam based on a sample of 3,117 Elderly People selected in community, Nguyen Dang Phai’s study [3] showed 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 [4] showed the hypertension prevalence of 28.4%.

1. Introduction (cont)

Khanh Hoa is a South-Central Province of Vietnam comprised of 8 district units with approximately population of 1.2 million. This survey aims at examining hypertension prevalence as well as related factors in Elderly People who is living in Khanh Hoa.

1. Introduction (cont)

2. Subjects and Method

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.

2. Subjects and Method (cont)Sample size was determined by the following formula:

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 Peole. Data collected were age, gender, ethnicity, systolic and diastolic blood pressures, height and weight.

Data were entered by EpiData Software version 3.1, analyzed by Stata version 10.0.

2)2

1(2 )1(

d

ppzn

3. Results and discussion3.1. Baseline data There were total of 2,170 Elderly People

seleted for the sample because of some missing and some under 60 years old. Over 60% of the sample was female, reflecting a larger proportion of female among Elderly population. More than 80% of them was at the age of under 80. The age group between 80 and 89 had only a proportion of 17%. Raglai Ethnic minority People accounted for 3% of Elderly population (Table 1).

Table 1: Baseline Characteristics of the Sample of Elderly People

Items Frequency(n=2,170)

Percent %

Gender:- Male- Female

8491,321

39.160.9

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

885866367502

40.839.916.9

2.30.1

Ethnicity:- Kinh- Raglai- T’rin- Others

2,095641

10

96.52.90.10.5

3.2. Anthropometric characteristics of Elderly People.

3.2.1. Weight Mean weight of the sample was 49 kg ±

8.7 kg. Mean weight of male was significantly higher than female (Table 2).

Table 2: Mean weight of Elderly People by genderGender Mean weight SD Test

Male (n = 849) 52.4 kg 8.5 kg t2168 = 15.025

p = 0.000…Female (n = 1,321) 46.9 kg 8.2 kg

Total (n = 2,170) 49.0 kg 8.7 kg

3.2. Anthropometric characteristics of Elderly People (cont)3.2.2. Height

Mean height of the sample was 155cm ± 7.3cm with the statistically higher mean among male Elderly (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 t2168 = 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. Anthropometric characteristics of Elderly People (cont)3.2.3. Body Mass Indeces (BMI)

Mean BMI of the sample was 20.26 kg/m2. There was no significant difference in mean BMI between men and women (Table 4).

Table 4: Mean BMI of Elderly People by genderGender Mean BMI SD Test

Male (n = 849) 20.40 3.01 t2168 = 1.683

p = 0.0926Female (n = 1.321) 20.17 3.14

Total (n = 2.170) 20.26 3.09

3.2. Anthropometric characteristics of Elderly People (cont) According to 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 proportions 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%)

χ2 = 2.7525p = 0.431

Normal 562(66.2%)

832(63.0%)

1,394(64.2%)

Overweight 45(5.3%)

77(5.8%)

122(5.6%)

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, were significantly different between men and women with higher mean blood pressures in men (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 t2166 = 3.313

p = 0.0009Female 1,319 135 20.9

Total 2,168 136 20.8

Diastolic blood pressure (mmHg)

Male 849 82 9.9 t2166 = 3.989

p = 0.0001Female 1,319 80 10.7

Total 2,168 81 10.4

3.3. Hypertension prevalence (cont)

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%, significantly higher than Nguyen Dang Phai’s and Dam Viet Cuong’s surveys. Hypertension among men was statistically higher than women: 52.2% vs 45.4% (Table 7).

3.3. Hypertension prevalence (cont) Comparing hypertension prevalence

among Kinh People and Raglai People who is the main ethnicity 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 urbunization and sedentary lifestyle in Kinh Pepole.

Table 7: Hypertension by Gender and Ethnicity

Gender Total Hypertension Percent Test

Gender

Male 849 443 52.2 χ2 =9.46

p = 0.002Female 1,321 600 45.4

Total 2,170 1,043 48.1

Ethnicity

Kinh 2,095 1,016 48.5 χ2 =8.8

p = 0.003Raglai 64 19 29.7

3.4. Association between blood pressure and anthropometric indeces

Scatter plots created by Stata software showed positive association between systolic blood pressure and BMI, age. Systolic blood pressure has increasing tendency proportional to BMI and age. Figure 1 and Figure 2 showed those associations.

Figure 1: Association between systolic blood pressure and age

100

150

200

250

sysB

P

60 70 80 90 100age

sysBP Fitted values

Figure 2: Association between systolic blood pressure and BMI

100

150

200

250

sysB

P

10.00 15.00 20.00 25.00 30.00 35.00bmi

sysBP Fitted values

3.4. Association between blood pressure and anthropometric indeces (cont) Analyzing those associations by

gender showed a stronger association in female than male in terms of systolic blood pressure and BMI as shown in Figure 4 and a stronger association in male than female in terms of systolic blood pressure and age as shown in Figure 3.

Figure 3: Association between systolic blood pressure and age by Gender

100

150

200

250

60 70 80 90 100 60 70 80 90 100

female male

sysBP Fitted values

sysB

P

age

Graphs by gender

Figure 4: Association between systolic blood pressure and BMI by Gender

100

150

200

250

10.00 20.00 30.00 40.0010.00 20.00 30.00 40.00

female male

sysBP Fitted values

sysB

P

bmi

Graphs by gender

3.4. Association between blood pressure and anthropometric indeces (cont)

Using multiple logistic regression, the model is showed below. However, this model is weak (R2 = 0,0329) log(sysBP) = 4,5391 + 0,0034*age – 0,0017 * gender * age + 0,0051*log(BMI)*genderin which 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 Male Elderly than Female (52.2% vs 45.4%), 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, BMI. Gender plays as an interaction role in multiple logistic regression model.

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=372058, 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.