Objective: To determine the province and ethnic specific prevalence and correlates of diabetes mellitus among Sri Lankan adults.

Method: A nationally representative sample of 5000 adults aged ?18 years was selected by a multistage random cluster sampling technique in this cross-sectional study conducted between 2005 and 2006.

Results: Response rate was 91% (n=4532), males were 40%, age 46.1±15.1 years (mean ±SD). The age-sex standardized prevalence (95% CI) of diabetes for Sri Lankans aged ? 20 years has been previously published as 10.3% (9.4-11.2%) [males 9.8% (8.4-11.2%), females 10.9% (9.7-12.1%), P=0.129). There was a marked variation in the province specific prevalence of diabetes with the highest (18.6%) in the Western and the lowest (6.8%) in the Uva provinces. The monthly income, BMI, waist circumference and per capita monthly expenditure were highest in the Western and lowest in the Uva. In contrast, the mean physical activity level was lowest in the Western province and highest in the Uva. However, the per capita daily energy consumption was lowest in the Western and highest in the Uva provinces.

The Sri Lankan Tamil ethnicity has the highest (22.1%) diabetes prevalence followed by the Sri Lankan Moor (21.4%). The Indian Tamil ethnic group living in the plantation sector had the lowest prevalence.

Conclusions: The provincial and ethnic distribution of diabetes closely resembled that of obesity (waist circumference more than the BMI) and the income level in the respective provinces and ethnic groups. The physical activity level had an inverse relationship. High level of physical activity had a protective effect from diabetes even when the energy consumption is high.