Abstract
Objectives: Several cross-sectional studies have reported on the prevalence of diabetes in India. However,
there are virtually no longitudinal population-based studies on the incidence of diabetes from India. The
aim of the study was to determine the incidence of diabetes and prediabetes in an urban south Indian
population.
Methods: The Chennai Urban Population Study [CUPS], an ongoing epidemiological study in two residential
colonies in Chennai [the largest city in southern India, formerly called Madras] was launched in 1996; the
baseline study was completed in 1997. Follow-up examination was performed after a mean period of 8
years. At follow-up, 501 [47.0%] subjects had moved out of this colonies and were lost to follow-up. Of the
remaining 564 individuals, 513 [90.9%] provided blood samples for biochemical analysis. Regression analysis
was done using incident diabetes as dependant variable to identify factors associated with development of
diabetes or pre-diabetes.
Results: Among subjects with normal glucose tolerance (NGT) at baseline [n=476], 64 (13.4%) developed
diabetes and 48 (10.1%) developed pre-diabetes (IGT or IFG). The incidence rate of diabetes was 20.2 per 1000
person years and that of pre-diabetes was 13.1 per 1000 person years among subjects with NGT. Of the 37
individuals who were pre-diabetic at baseline, 15 (40.5%) developed diabetes [incidence rate: 64.8 per 1000
person years], 16 (43.2%) remained as pre-diabetic and 6 (16.2%) reverted to normal during the follow-up
period. Regression analysis revealed obesity [Odds Ratio (OR): 2.1, p=0.001], abdominal obesity [OR: 2.23,
p<0.001] and hypertension [OR: 2.57, p<0.001] to be significantly associated with incident diabetes. The Indian
Diabetes Risk Score (IDRS) showed the strongest association with incident diabetes [OR: 5.14, p<0.001].
Conclusion: The study shows that the incidence of diabetes is very high among urban south Indians.
While obesity, abdominal obesity and hypertension were associated with incident diabetes, IDRS was th
