Diabetes in rural Pondicherry, India: a population-based studyof the incidence and risk factors.

BACKGROUND: For India, the 'diabetes capital' of the world, it is essential to know the incidence of type 2 diabetes mellitus (T2DM) and its key determinants. As two thirds of Indians live in rural areas, a study was undertaken to assess the incidence and risk factors of T2DM in rural Pondicherry, India. METHODS: In a population-based cohort study initiated in 2007, a sample of 1223 adults > 25 years ofage from two villages of Pondicherry were selected using cluster random sampling. Data on risk factor exposure were collected using a structured questionnaire, anthropometric tests and fasting blood glucose assessment. During house visits, 1223 of 1403 invited subjects participated. Of these, 71 (5.8%) were found to have diabetes. In 2010-2011, 85% of the non-diabetics (979/1152) were followed up using the same protocol. We calculated the risk of T2DM per annum standardized by age and sex. Population estimates of the risk factors associated with T2DM were analysed using the Generalized Estimating Equation model and the Population Attributable Risk (PAR) for T2DM calculated. RESULTS: During 2937 person-years (PY) of follow-up, 63 new cases of T2DM occurred, giving an incidence rate of 21.5/1000 PY. Almost one third (31.7%) of cases occurred in people aged below 40 years. The incidence was double among males (28.7/1000 PY; 95% confidence interval (CI): 21.0-38.7) compared with females (14.6/1000 PY; 95% CI: 9.4-21.7). Applying these rates to rural populations, it is estimated that each year 8.7 million people develop T2DM in rural India. Nearly half of the T2DM incidence was attributed to overweight/obesity and alcohol usage. CONCLUSION: T2DM incidence was 2% per year in adults in rural Pondicherry, India, with the rate increasing twice as fast in men. Increasing age, obesity, alcohol use and a family history of T2DM independently predicted the development of diabetes. As half of T2DM incidence was attributed to overweight/obesity and alcohol use, health promotion interventions focusing on maintaining an optimal weight and decreasing alcohol consumption may be effective in reducing the rise in T2DM cases.