Prevalence of Cardiovascular Disease Risk Factors in an Indigenous Vedda Community in Sri Lanka: Do These Communities Need a Targeted Health Promotion Strategy?

Background: The indigenous population in Sri Lanka called “Veddas” estimated to be around 0.05% of the total population in the island. This population is unique that they used to live mostly in jungles with primitive lifestyles. The objective was to study the cardiovascular risk factors in this indigenous (Vadda) community. Methods: A descriptive cross-sectional study was carried out with convenience sampling method, by inviting all adults (> 18 years) in the indigenous village Pollebedda. Height, weight and blood pressure was measured, and fasting blood samples were analyzed for glucose, lipids and haemoglobin. Data were analyzed using SPSS (version 22)0. Results: Response rate was approximately 39%. Out of total 121 participants 47 were males and 74 were females. The mean age was 44.29 +14.75 years and 12 were elders> 65 years of age. In the sample 17.3% were obese (BMI>27.5) while 24.8%% were overweight (BMI 23-27.5). The crude prevalence of diabetes, hypertension and raised total cholesterol were 7.2%, 12.4% 7.7% respectively. Prevalence of low HDLC (< 40mg/dL in men,< 50 mg/dL in women), high LDLC (>160 mg/dL) and elevated triglycerides (>150mg/dL) were 75.2%, 7.7% and 25.6% respectively. Isolated hypertriglyceridemia was present in 20.5%. Conclusions: There is a rising trend of obesity and diabetes in this indigenous community compared to previous study. This highlights that the indigenous peoples in Sri Lanka share the relatively high rates of coronary artery risk factors observed among other indigenous groups around the world. Changes in lifestyle and diet, poverty, poor health seeking behavior and limited access to health care due to limitation in transport are possible risk factors for this trend which needs to be further evaluated. A local and global initiative is required to control cardiovascular disease risk factors among indigenous groups.

coronary artery risk factors observed among other indigenous groups around the world. Changes in lifestyle and diet, poverty, poor health seeking behavior and limited access to health care due to limitation in transport are possible risk factors for this trend which needs to be further evaluated. A local and global initiative is required to control cardiovascular disease risk factors among indigenous groups.

Background
Indigenous population in Sri Lanka is a unique population by the name of "Veddas". They are traditionally forest dwellers. Total Vedda population in Sri Lanka is estimated to be around 0.05% of the total Sri Lankan population (22. 15 Adult population (>18 years of age)in Pollebedda is 60% 15 which is around 312.
Studies on health of indigenous populations in Sri Lanka area limited. Their unique lifestyles and origins may incur a different set of risk factors for cardiovascular disease. One study carried out in an indigenous population in 1991, found that hypertension was rare and obesity was absent which was attributed to high levels of physical activity. 1 The low prevalence of coronary heart disease was due to favorable coronary risk pro le. 1 According to a survey in 2006, the prevalence of diabetes in rural Sri Lankans is estimated to be 8.7% compared to national prevalence of 10.3%. 10 Earlier study in 2004 involving 4 provinces has shown that there were marked regional differences in the prevalence of diabetes and obesity. 4 A study done in an indigenous population in Pollebedda (2013) revealed that prevalence of diabetes was 2.1%. 13 Ancient traditional lifestyle with high level of physical activity involving hunting and natural diet may have been protective in terms of development of diabetes. The risk of changing lifestyle which is evident even in these communities which may contribute to different set of risk factors.
We therefore carried out a health survey in an indigenous population living in Pollebedda an indigenous village situated about 320km from Colombo in eastern province focusing mainly on cardiovascular disease risk factors.
Our objective was to study the prevalence of obesity, diabetes, hypertension and dyslipidemia among a selected indigenous (Vadda) population of Sri Lanka.

Methods
Descriptive cross-sectional study was carried out with a convenience sampling method due to the small size of the population. All adult residents (> 18 years) of the indigenous community were invited for a health screening programme through the head of the indigenous society and the medical o cer of health of the region. Total number of participants were 121. The response rate was around 39% considering the approximate total adult indigenous population of 312. Pregnant mothers, individuals currently suffering from acute illnesses and those with di culties in communication were excluded. Validated interviewer administered questionnaire was administered after obtaining informed written consent.
Height was measured to the nearest 0.5 cm and weight were measured to the nearest 100mg using calibrated equipments by trained nurses adhering to the WHO guidelines. 5,9 Body mass index (BMI) was calculated (kg/ m2) and risk strati cation was done according to WHO risk categories for Asians. 22 Blood pressure was measured in seated position after resting using Omron IA2 digital blood pressure monitor by the investigators at the site. Each measurement was done twice. 6 Fasting venous blood was drawn and collected into sodium uoride/potassium oxalate, plain and EDTA tubes by trained phlebotomists for analysis of blood glucose, lipid pro le and full blood count. Blood samples were transported to Medical Research Institute, Colombo at 4 o C on the same day (within 8-10 hours of collection) and was centrifuged, serum separated and frozen. Full blood count was analyzed on the same day. Fasting plasma glucose was measured in AU480 Beckman Coulter fully automated biochemistry analyzer by hexokinase method. Lipids were measured by enzymatic method in the same analyzer. Participants with fasting blood glucose more than 100 mg/dL and normal hemoglobin were further screened with HbA 1 C.
Diagnoses were based on the following criteria: Diabetes was diagnosed according to American Diabetes Association guidelines (ADA), based on fasting plasma glucose (FPG) level of ≥126 mg/dl or on insulin or oral hypoglycemic drugs within the past 4 weeks. FPG ≥100 mg/dl but <126 mg/dl was considered as Impaired Fasting Glucose (IFG). 10 Hyperlipidemia was de ned according to the National Cholesterol Education Program Adult Treatment Panel -III guidelines; high total cholesterol (>240 mg/dL) low HDLC (< 40mg/dL in men, < 50 mg/dL in women), high LDLC (> 160 mg/dL) 2,3 and high triglyceride (>150mg/dL).
According WHO guidelines for Asians, the following cutoffs were taken.
Follow up visits were arranged in the Base Hospital Mahaoya to all participant who were diagnosed to have diabetes, hypertension and dyslipidemia. Data analysis was done using SPSS-version 22.

Results
There were 121 participants and 47 were males and 74 were females. The age range was 18 to 90 years (median 43 years; mean 44.29 +14.75). Twelve participants were over 65 years of age (9.9%).

Diabetes
Due to some participants not in fasting state and errors in collecting blood, only 111 samples were received for FPG analysis. There were 8 individuals with diabetes (7.2%) and 2 individuals with impaired FPG.

Hypertension
Blood pressure was recorded from 113 participants as some participants did not get their blood pressure checked after the period of rest. There were 14 participants with hypertension (12.4%).
Among the obese (BMI>27.5) subjects (22), lipid analysis was done in 20 and 18 (90%) of them had some kind of dyslipidemia. Out of the non obese (99) lipid analysis was done in 97. Only 66 (67%) of non-obese subjects assessed had dyslipidemia. The difference was not statistically signi cant(p=0.057).

Discussion
The results suggest that the indigenous people have a different risk factor pro le for cardiovascular disease (i.e. comparable rates of obesity and lower rates of DM, hypertension and dyslipidemia except HDL levels) compared to those living in urban and rural areas. One likely explanation for this could be the changes in life styles resulting in increasing rates of over-weight and obesity, while the prevalence of diabetes and hypertension have lagged behind. If this hypothesis is correct, this population group would face higher rates of these diseases in the near future.
In Sri Lanka, the prevalence of obesity, overweight, hypertension and diabetes are higher in urban than rural areas. A study done in 2012 in Kaluthara district showed that obesity was more prevalent in urban areas and among rich people. 7 SLDCS data in [2005][2006] showed that diabetes prevalence was signi cantly higher in the urban population compared with rural; 16.4% vs. 8.7% (P < 0.001). A study done in 2012 in Kaluthara district has shown that diabetes was more prevalent in urban areas and among rich and a uent people, which indicated that Sri Lanka was in the early stage of the epidemic. 8 The projected diabetes prevalence in Sri Lanka for the year 2030 is 13.9%. 10 Though there are differences in the prevalence according to regions and social strata, Sri Lanka as well as the entire world will experience a marked rise in obesity and diabetes in the future. Rural and indigenous communities may lose their immunity against such trends as suggested by recent studies.
Although the response rate is around 39%, our data shows that the current rates of obesity and diabetes in indigenous people have increased compared to the study in 2013 in Pollebedda. 14 Rising trends of Diabetes in our population warrants further studies into risk factors particular to this population. Contributing factor may be change in dietary pattern consist of more carbohydrates as appose to the traditional diet consisting high ber and high protein. 15 Particularly in the Vedda community this may be due to change in life style which earlier consist of traditional hunting but now predominantly farming and having access to high calorie food. 15 Rising trend of both diabetes and obesity in our population raises possibility of obesity as a cause of the diabetes epidemic even in this community. Though this study was from a single Vedda community, it is compatible with global trend seen with regards to cardiovascular risk factors in indigenous populations. Although there's genetic variations among different indigenous populations around the world due to evolution and anthropological factors, evidence is there to indicate that there is de nitely a rising trend in cardiovascular risk factors in indigenous communities. Studies from several countries show that the indigenous communities have higher prevalence rates of obesity and diabetes than the national average.
Prevalence of obesity and diabetes in Australian indigenous aboriginal population (2.5% of total population) are 27% and 7% compared to national prevalence of 22% and 4%, repectively. 18 Similarly, in New Zealand Maori indigenous population (15% of total population), the prevalence of obesity and diabetes are 42% and 8% compared to national prevalence of 27% and 5%, respectively. 18 In USA, in indigenous American Indians and Alaskans (1.7% of total population), the prevalence of obesity and diabetes are 42% and 15% compared to national prevalence of 33% and 8%, respectively. 18 Furthermore, population surveys in these 3 countries have shown that compared to non indigenous population, indigenous population shows higher rates of unhealthy dietary habits and sedentary behavior patterns. 18 In Malaysia, Orang Asli indigenous population (0.6% of total population), the prevalence of obesity and diabetes are 16.8% and 4.6% compared to national prevalence of 17.7% and 20.8%, repectively. 20 There is a rise in the prevalence of cardio metabolic risk factors in indigenous tribes in Malaysia when compared to 20 years ago where urbanization has been implicated as a possible cause. 20 More recent study involving Canadian First Nations communities (indigenous population) in 2018 showed that poor education, racism, di culty accessing routine health care and not having access to a primary health care provider are some of the risk factors associated with higher rates of cardiovascular disease. 19 Furthermore, it was revealed that greater the burden of socioeconomic hardship, the greater the burden of cardiovascular risk factors for a given community. 19 In a central Australian aboriginal community in 2009, depression and unemployment were identi ed as risk factors for having increased risk for cardiovascular disease. 20 In Sri Lanka, these scattered groups of indigenous populations are undergoing demographic transition (9.9% elders above 65 years in our study vs. 8.1% nationally). Furthermore, they experience greater socio economic hardship due to social isolation and poverty. 15 Poor health care seeking behavior and limited access to health care due to limitation in transport are clearly identi ed in these communities, particularly as these communities are among the poorest in the country with most families having a household income of less than Rs.5000/= per month. 15 In Australia as well cardiovascular risk factors in indigenous communities were associated with psychological factors and socioeconomicindicators. 21 A comprehensive strategy involving identi cation of unique risk factors, implementation of culturally appropriate preventative measures and improving accessibility to health care is highly recommended to prevent exponential rise in risk factors for cardiovascular diseases such as obesity and diabetes in these indigenous communities. Because it is clearly evident that Sri Lankan indigenous community is also following the global trend of increasing cardiovascular risk factors in indigenous populations. Potential local strategy would be implementing a separate health promotion strategy in the districts with indigenous communities, targeting prevention of cardiovascular risk factors using dietary modi cations and physical activities which is acceptable to their cultures.
As studies from several countries indicate that the indigenous populations are increasingly susceptible to develop obesity and other coronary artery risk factors preventative strategies targeting indigenous communities are coming to the focus of discussion in other countries as well. 17

Conclusions
There is a rising trend of obesity and diabetes in this indigenous community compared to previous study. This highlights that indigenous peoples in Sri Lanka share the relatively high rates of coronary artery risk factors observed among other indigenous groups around the world. A local and global initiative is required to control cardiovascular disease risk factors among indigenous groups through a targeted health promotional strategy.