High prevalence of diabetes and impaired glucose tolerance in India: National Urban Diabetes Survey.

There has been no reported national survey of diabetes in India in the last three decades, although several regional studies show a rising prevalence of diabetes. The aim of this study was to assess the prevalence of diabetes and impaired glucose tolerance in six major cities, covering all the regions of the country. Using a stratified random sampling method, 11216 subjects (5288 men; 5928 women) aged 20 years or above, representative of all socio-economic strata, were tested by OGTT. Demographic, anthropometric, educational and social details were recorded using a standard proforma. Physical activity was categorised using a scoring system. Body mass index (BMI) and waist-to-hip ratio (WHR) were calculated. Glucose tolerance was classified using the 2-h values (WHO criteria). Prevalence estimations were made taking into account the stratified sampling procedure. Group comparisons were done by t-test or analysis of variance or Z-test as relevant. Univariate and multiple logistic regression analyses were used to study the association of variables with diabetes and impaired glucose tolerance. Age standardised prevalences of diabetes and impaired glucose tolerance were 12.1% and 14.0% respectively, with no gender difference. Diabetes and impaired glucose tolerance showed increasing trend with age. Subjects under 40 years of age had a higher prevalence of impaired glucose tolerance than diabetes (12.8% vs 4.6%, p < 0.0001). Diabetes showed a positive and independent association with age, BMI, WHR, family history of diabetes, monthly income and sedentary physical activity. Age, BMI and family history of diabetes showed associations with impaired glucose tolerance. This national study shows that the prevalence of diabetes is high in urban India. There is a large pool of subjects with impaired glucose tolerance at a high risk of conversion to diabetes.