OBESITY AND DIABETES IN AN INDIGENOUS “VADDA” POPULATION OF RURAL SRI LANKA

Indroduction: Economic development and the associated lifestyle changes have led to a rise in prevalence of diabetes among adult population of Sri Lanka. A Similar lifestyle changes are observed among indigenous population (Vadda) population of Sri Lanka. However, there is limited data available regarding prevalence of diabetes among Vadda population in Sri Lanka. This study was conducted to determine the prevalence of type 2 diabetes, impaired fasting glycaemia (IFG) and obesity among rural indigenous Vedda population of Sri Lanka.

Obesity and the associated type 2 diabetes are two major global health problems. The recent epidemiological data suggest that the incidence of diabetes is rising (1) and the south Asian countries have a very high incidence of type 2 diabetes (2). According to a study done in 2005 covering seven provinces, the prevalence of diabetes and any form of dysgycaemia in Sri Lanka was 10.3% (9.4-11.2%) and 21.8% (20.5-23.1%) respectively.
Vadda is a common term used to describe the indigenous population of Sri Lanka. This tribal community university of Colombo in 2011, only 10% this population is involved in Paddy farming and 50% of these families are involved in Chena cultivation (a form of slash and burn cultivation) and 15% work as manual laborers mainly on adjacent villages as the main form of employment (3). Currently, Vaddas are among the poorest communities of the country. Traditionally, they had only two main meals per a day and even today only about 65% of families eat 3 meals a day and 52% of families had income less than Sri Lankan Rupee 5000 ($40) a month.
With the transition from hunter gatherers to more farming community, their dietary patterns have is believed to be related to pre historic communities of the country and have being living in Sri Lanka for a longer period than the current main communities such as Sinhalese, Tamils and Muslims. Currently, it is estimated that there are about 10, 000 Vaddas living in small clusters scattered over central and eastern parts of Sri Lanka. They have their own unique culture, language, religion and rituals. Their habitat is within or adjacent to forest areas of the country. They are traditionally hunter gatherers who lived on by hunting small animals, mainly deers and monkeys for food and gathering yams and honey from the forest. changed quite remarkably with time and now their diet mainly consists of carbohydrates such as Maize, Kurakkan, Rice and yams and legumes such as Cow pea in addition to the small quantity of protein they gather by hunting monkeys, deer, wild boar and monitor lizards. This gradual transition from hunting community to a farming community has made them less active and to eat more carbohydrates. This lifestyle shift seems to have dramatic consequences for the prevalence of obesity and diabetes in this community. The objective of this study was to study the prevalence of obesity and diabetes among the indigenous (Vadda) population of Sri Lanka.
Data were analyzed with SPPSS 10.5 software. Prevalence of diabetes and pre-diabetes were calculated and the prevalence of obesity according to BMI and abdominal obesity was calculated and compared with national values.

RESULTS
Weights were measured with light clothes without shoes using a calibrated weighing scale. The height was measured while the subject standing in erect posture vertically touching a wall looking horizontally. The WHO protocol for measuring waist circumference was adopted and the measurement was made at the approximate midpoint between the lower margin of the last palpable rib and the top of the iliac crest with a plastic tape (4).
Using aseptic precaution, 5ml of venous blood was taken for fasting plasma glucose using aseptic precautions and plasma glucose levels were assessed by the glucose oxidase (enzymatic oxidation) method. Fasting blood sugar of more than 127 mg/dl and 100-126 mg/dl were used to diagnose diabetes and impaired fasting glucose (IFG) respectively (5).
The BMI levels were calculated according to WHO risk categories for Asian BMI (6). BMI of less than 18.5 kg/m 2 was considered as underweight, a BMI of 18.5-23 kg/m 2 was considered as increasing but acceptable risk, a BMI of 23-27.5 kg/m 2 as increased risk and a BMI of 27.5 kg/m 2 or higher as high risk.
The abdominal circumference was classified according International Diabetes Federation criteria for ethnic or country-specific values for waist circumferences and the waist circumference of males more than 90 cm and females more than 80 cm This study was conducted in February 2013 and the study population was selected from a remote village called Pollebedda inside the Galoya national wildlife sanctuary, which is about 300 kilometers from Colombo, in the Ampara district, eastern province of Sri Lanka. According to government statistics, there were 455 families with a total population of 2407 including children (1506 males and 901 females) in this village. With the assistance of the head of the indigenous clan and the cultural officer of the District secretariat, 25 houses were selected for the study. All the adults in those houses, age more than 25 years were included in the study.
Each house was visited on the day previous to the study and they were informed about the objectives of the study and the procedural details including overnight fasting and venesection for blood sampling. After obtaining informed consent, they were kept fating after 10 p.m. A team of nurses and doctors of General Hospital Ampara volunteered to visit the houses and to collect blood samples and anthropometric data on the following day. None of the adults refused consent for the study.  (Table 1). These values were lower compared to national values of BMI for males and females, which are 21.1 kgm -2 (20.9-21.3 kgm -2 ) and 22.3 kgm -2 (22.1-22.4 kgm -2 ) respectively (8).    (10). The prevalence of IFG in Vadda population is 5.5% (7.5% for males and 3.9% for females), which is lower than the national figure for rural population of Sri Lanka (8.6% for men and 7.7% for women) (Table 4).

Males (n=40) Females (n=51)
habits and the level of activity during daily activates, the prevalence on non-communicable diseases were very much lower in these communities compared to the general population. However, with the lifestyle changes towards a modern society has caused a major shift in the prevalence of obesity, diabetes and IFG among these tribal communities and this change is seen even among our indigenous communities (3,9). In the isolated Vadda community that we studied, the prevalence of obesity, diabetes and IFG were still very much lower compared to rural population of Sri Lanka. However, the underweight problem is still a concern.    (1958). This population was relatively isolated from other communities as they live away from main roads in a wildlife sanctuary and considered unsafe to travel during the last 30-year period due to the civil war. Therefore, the life style of this community has change very little over the past three decades. The lack of environmental influence with the economic development that we see in other communities, is probably the reason for low incidence of diabetes and IFG in this community. Their active lifestyle could have been another strong protective factor. Whether there is a genetic contribution needs to be investigated further.

DISCUSSION
The incidence of obesity was very much lower among Vadda population compared to the rural community of Sri Lanka and this could be due to their active life style, which involves significant amount of walking for hunting and hard labor in the fields. However, poverty has a direct relationship with the prevalence of malnourishment and the underweight problem of a community and this probably is playing an important role for the higher prevalence of underweight problem among adults of this tribal community. Although there is an improvement of malnutrition and underweight problem when com-pared with previous studies done in 1969 and 1996 in similar populations,

REFERENCES
there is a lot to be done to improve the nutritional status of this community.
Due to the change in the lifestyle during the last few decades, there has been a change in the prevalence of diabetes and IFG among Vadda population of other areas and it is almost similar to prevalence in rural communities of Sri Lanka (10). These findings highlight the importance of early interventions in related to the appropriate health promotion interventions to avoid malnutrition without creating a situation of overnutrition for this indigenous community of Sri Lanka.

CONCLUSIONS
Due to the rapid urbanization and the modern lifestyle, obesity and diabetes have become major health problems. However, the prevalence of obesity and diabetes are very much lower among indigenous community of Sri Lanka. Although there has been an improvement with the prevalence of malnutrition and underweight problem in this community, it is a health concern that needs to be addressed by the health authorities.