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Paper Presented in the Conference
Cardiovascular disease and risk factors among 345 adults in rural India
- the Andhra Pradesh Rural Health Initiative
Clara Chow1,4, Magnolia Cardona1, P Krishnam Raju3,
S lyengar2, A Sukumar2, Ravi Raju2, Sam
Colman1, P Madhav2, Rama Raju2, David
Celermajer4, Bruce Neal1
1 The George Institute For International Health, University
of Sydney, PO Box M 210, Missenden Road, Sydney 2050, Australia; 2
Byrraju Foundation, Hyderabad, India; 3 CARE Foundation,
Hyderabad, India; 4 Royal
Prince Alfred Hospital, Sydney, Australia
Contact:
Dr Clara chow
The George Institute
POBoxM20I
Missenden Road
Sydney, NSW 2050
Phone 612 9993 4566
Fax 61299934502
Email cchow@thegeorgeinstitute.org
Page 1 of 184S
ABSTRACT
Objectives
To investigate the levels and management of major cardiovascular risk
factors and the prevalence of cardiovascular disease in two villages in
rural Andhra Pradesh, India.
Methods
A cross-sectional survey was done by selecting a random sample
stratified by age and gender from each village using census lists
compiled in 2002. For each individual, trained study staff administered
a structured questionnaire, performed a brief physical examination and
collected a fasting venous blood sample. Weighted estimates of mean (or
percentages with) risk factor levels in the population were calculated
with standard errors.
Findings
Data was collected from 345 adults aged 20 to 90. The average household
size was 4.2 and the mean combined household income was about Indian
Rupees 25,454 (US$580) per year. The mean blood pressure was 116/73 (l/l)mmHg,
total cholesterol 179 (2)mg/dL, HDL-cholesterol 32 (0.3)mg/dL, LDL-cholesterol
124 (2)mg/dL and triglyceride 113 (4)mg/dL. The prevalence of current
smoking was 20 (2)%, hypertension 20 (2)%, diabetes 3.7(0.2)%,
overweight 16.9 (2.3)% and obesity 4.4 (1.2)%. A medical diagnosis of
cardiovascular disease (previous heart attack, stroke or angina) was
reported by 2.5 (0.7)% and a further 1.1 (0.5)% had angina by the 'Rose'
classification.
Conclusions
Cardiovascular disease and risk factors in rural areas of countries such
as India represent a major international public health concern. New
treatment and prevention strategies suitable for use in resource poor
settings are urgently required.
INTRODUCTION
Cardiovascular diseases are the leading causes of death worldwide,
accounting for an estimated 14 million deaths in 1990 and projected to
cause 25 million deaths in 2020. The majority of cardiovascular deaths
in 1990 occurred in economically developing countries and it is
economically developing countries such as India that will see the
greatest increase in cardiovascular deaths over the next few decades1,2
The growth in cardiovascular disease in India has been particularly
pronounced in urban areas but many vascular deaths also occur in rural
regions and this is still where the majority of the population lives.
While there is some limited information about the causes and management
of cardiovascular disease in urban regions corresponding data for rural
regions is scant.3,4
The Andhra Pradesh Rural Health Initiative (APRHI) has been developed as
a collaboration between four partners (listed in acknowledgements)
seeking to discover new information that will improve the health of
Indians living in rural areas. The wider initiative includes components
addressing mortality surveillance, causes of disease and treatment and
prevention strategies with a particular focus on non-communicable
conditions. We report here the findings of a survey done to investigate
the determinants of cardiovascular disease and current cardiovascular
disease management strategies among adult Indians living in two villages
participating in APRHI.
METHODS
This survey was conducted in June 2004 as a collaboration between
partners in India and Australia. The study was approved by the Ethics
Committees of the CARE Hospital, Hyderabad in India and the University
of Sydney in Australia. All participants provided written informed
consent and the study was conducted in line with the Declaration of
Helsinki and subsequent amendments.
The sample design
Two villages from the 137 villages participating in the Byrraju
Foundation Rural Development Program were identified for this pilot
study. One less developed village (Rajupalem, about 3 hrs drive from
Bhimavarum, the main town in the area), smaller in size with a younger
population and lower average income and one more developed village (Palakoderu,
about 20 minutes drive from Bhimavarum) with a larger, older population
and higher average income.
A random sample stratified by age and gender was selected from each
village. This was done using census lists compiled by the Byrraju
Foundation in 2002. In brief, the registered population of each village
aged 20 years and above was divided into ten strata defined by age
(20-34, 35-44, 45-54, 55-64, 65+) and gender. We then randomly sampled
the same fixed number of individuals within each stratum and invited
these individuals to attend for study.
Data collection and measurements
For each individual that consented to participate, trained study staff
administered a structured questionnaire, performed a brief physical
examination and collected a fasting blood sample. Our questionnaire was
developed from other validated questionnaires5,6,7 and other
technical publications using expert advice from a range of sources.8,9
The questionnaire sought information on socio-demographic variables
(including education level, household income and occupation),
cardiovascular risk factors, current treatments and knowledge and
attitudes towards cardiovascular disease. The examination included two
measurements of blood pressure (measured using an omron M2 manual
inflation blood pressure monitor), measurement of body weight, height,
waist and hip circumference with participants wearing clothes without
shoes.
Venous blood samples for biochemical analysis were obtained after an
8-hour overnight fast. Samples were stored immediately over ice and
transferred to the study laboratory in Bhimavarum within 4 hours of
collection. All analyses were performed using a Hitachi Boeringer
Mannheim 902 Automatic analyzer and Elecys 1010. Quality control and
standardization was achieved through the analysis of internal and
external quality assurance materials provided by the Royal College of
Pathologists Australia quality control program run concurrently with
study bloods.
Definitions
High blood pressure was defined as mean systolic blood pressure
>140mmHg, and/or mean diastolic blood pressure >90mmHg, and/or treatment
with Western blood pressure-lowering medication.10 High total
cholesterol was defined as fasting total serum cholesterol >240mg/dL and
dyslipidaemia was defined as one or more of total cholesterol >240mg/dL,
LDL >160mg/dL or HDL <40mg/dL based on ATP III Guidelines.11
Diabetes was defined as fasting plasma glucose >126 mg/dl12
or a previous diagnosis of diabetes. Overweight was defined as body mass
index (BM1) >25kg/m2 but <30kg/m2 and obesity as BMI >30 kg/m2.13
Sedentary lifestyle was defined as answering "almost none" to level of
physical activity during and after working hours. Cardiovascular disease
was defined as a previous medical diagnosis of heart attack or stroke or
a positive Rose Angina questionnaire.14, 15
Statistical analysis
Weighted estimates (with standard errors) of mean, or percentage risk
factor levels in the overall population aged 20 years and over and among
age and sex sub-groups were calculated. Comparisons of risk factor
levels between population sub-groups were performed using independent
t-tests for continuous variables and x2 -tests for
categorical variables and proportions. All analyses allowed for the
clustering effects associated with the survey design. There were ten
strata defined by the five age groups and gender in each village and
weights were the population to sample size ratios for each combination
of age, sex and village. All analyses were done using STATA 8.0.
RESULTS
Recruitment an d response rates
A total of 600 individuals were invited to participate in the study and
345 (58%) were located, agreed to participate, gave informed consent and
presented for interview. Among the 345 participants the data from the
questionnaire, physical examination and blood tests were all more than
99% complete. Between 10 and 24 individuals were sampled in each of the
)0 age, sex groups in each village. The response rate was higher in
Palakoderu than. Rajupalem (62% versus 53% p=0.03) and among females
than males (62% versus 53% p=0.03) with some variation between different
age groups (Table 1).
The average age of the adult population in these two villages was 41
(range 20 to 90 years) and this was the same for men and women (Table
2). 50% were male and 79% were married. The mean number in each
household was 4.2 (range 1-18) people and the . average combined
household income was 25,454 (1429) rupees (about US$580) per year.
The estimated overall mean blood pressure was 1 16/73 (standard error
I/]) mmHg, the mean total cholesterol 179 (2)mg/dL, the mean HDL
cholesterol.32 (p.3)mg/dL, the mean . calculated LDL cholesterol 124
(2)mg/dL and the mean triglyceride level 113 (4)mg/dL (Table 3). The
mean fasting plasma glucose was 75 (l)mg/dl the mean body mass index
(BMP) was 21 (0.3)kg/m2 and II (2)% of the population reported a
sedentary lifestyle. The percentage of current smokers in the population
was 20 (2)%, chewing tobacco was used by 3 (l)% and passive smoking of
one or more hours per day was reported by 50 (3)%. There were some
differences between men and women (Table 2).
Prevalence and treatment of selected
cardiovascular disease states
The prevalence of hypertension was 20 (2)% and the prevalence of ATP111
defined dyslipidaemia was 91 (2)%. Dyslipidaemia was primarily as a
consequence of 87 (2)% having low HDL with only 13 (2)% having cither a
high total cholesterol or a high LDL. Diabetes was identified in 3.7
(0.2)% of the population with 2.6 (0.8)% of the population aware they
had diabetes prior to the survey. The prevalence of overweight (BM1>25)
was 16.9 (2.3)% and obesity (BMI > 30) 4.4 (1.2)%. A medical diagnosis
of cardiovascular disease (previous heart attack, stroke or angina) was
reported by 2.5 (0.7)% and a further 1.1 (0.5)% had 'Rose questionnaire
definite angina'.
Treatment and prevention of cardiovascular
disease
An estimated 58 (3)% of the population reported having their blood
pressure checked in the prior 12 months and 14.3 (1.9)% of the village
population were receiving Western blood pressure lowering medication.
6.7 (1.3)% reported a cholesterol check in the same period and 2.9
(0.7)% were using cholesterol lowering therapy. Regarding knowledge of
behavioral risk factors, 93 (1.7)% of the population were aware that
weight loss was important. 89 (1.8)% were aware that smoking cessation
was important, 88 (2.2)% were aware that exercise was important, 89
(2.0)% were aware that alcohol consumption was important and 95 (1.2)%
were aware that fat intake was a key factor in cardiovascular disease.
DISCUSSION
This survey provides up-to-date information about the levels of
cardiovascular risk factors and the prevalence of cardiovascular
disease, as well as selected information about the management of these
conditions in two villages in rural Andhra Pradesh. The findings show
that important determinants of cardiovascular disease are highly
prevalent and that while community knowledge about cardiovascular
disease is quite good, management of risk factors remains suboptimal.
The risk factor levels identified in these villages are above those
reported from previous studies conducted in rural areas 2,3,16
although still below those typically observed in urban parts of India
3,17 or in Western countries.18 However, heart
attack and stroke are likely now the leading cause of death in villages
such as those studied1,2 and data from the type of survey
done here provide important insight into the possible reasons for this.
Most of the survey findings are highly plausible and broadly consistent
with the economic status of the area. Levels of use of blood pressure
medications have almost certainly been elevated by a hypertension
detection and treatment program that has been in place for several
years. The very high proportion of participants with dyslipidaemia by
ATP III criteria 11 is, however, probably importantly
misleading. The low HDL cholesterol levels responsible for the diagnosis
in most individuals is generally in the context of concurrent low total
and LDL-cholesterol levels and in this scenario may not indicate a high
level of lipid-related risk. This is an issue that has been noted in
other such studies9 and highlights the need for either
different reference ranges for different populations or else a greater
focus on indicators of risk such as cholesterol ratios.19
The population sampling and weighting method utilized in this study is
well-established and should provide reliable estimates of risk factor
levels and disease prevalence. Unfortunately not all invited
participants were able to attend our survey and it is possible that this
may have impacted on the reliability of some of our results.
Non-response of invited participants was in part a consequence of the
census data being outdated (a number of selected participants had
migrated) and in part because some members of the population were unable
to attend due to work or other prior commitments. In future surveys,
updating of the population census data, earlier and repeated invitation
of participants, flexibility of appointment days and timing of the
survey for a non-harvest, non-planting agricultural season would likely
significantly increase the response rate. Our relatively small sample
size has also limited out ability to estimate precise means and
frequencies of the various risk factors in different age and sex groups.
While some such differences are apparent a study of larger size may
identify other significant differences between age and sex groups and
between villages.
With the epidemiological transition rapidly progressing in many
developing countries2 the development of cardiovascular
treatment and prevention programs that are suitable for use in resource
poor rural settings is a public health priority. To design such programs
will require reliable information about disease prevalence and disease
determinants and this study clearly demonstrates the feasibility of
obtaining such data. Our project was done in just a few weeks and the
total cost for the survey was just a few thousand dollars including all
local salaries, all assays, transport, accommodation and subsistence and
rental of all necessary equipment. Larger surveys that could provide
more precise and reliable disease and risk factor estimates in different
developing regions are eminently feasible and affordable and would
provide valuable additional insight.
ACKNOWLEDGEMENTS
APHRI has been developed as a collaboration between four
partners, The Byrraju Foundation in Hyderabad, India, The Center for
Chronic Disease Control (CCDC) in Delhi, India, The Care Foundation in
Hyderabad, India and The George Institute for International Health in
Sydney, Australia. We acknowledge the support of Dr. Viviek Chaturvedi (CCDC):
Professors David Celermajer and David Sullivan of Royal Prince Alfred
Hospital Sydney, Australia; Dr. Koteswara Raju and colleagues from the
Bhimavaram DNR College in India; and Dr. K Lakshmi Pathiraju from the
Bhimavaram Hospital in India. We also would like to thank the
chairpersons, village committees and communities of Rajupalem and
Palakoderu for their tremendous support of the project. This work was
funded by The Byrraju Foundation, Hyderabad.
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Table 2
Table 3
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