Prevalence and incidence of type-2 diabetes and impaired glucose tolerance in a selected Indian urban population

Abstract

Aim: To study the impact of diabetes mellitus on a selected Indian urban population.

Methods: The staff of Indian Institute of Technology in Chennai and their relatives were screened for diabetes by oral glucose tolerance test (OGTT) in 1992. But those on treatment for diabetes were not screened by OGTT. All those found to have diabetes during initial screening were excluded from further follow-up. Those without diabetes were followed with repeat OGTT one year later in 1993.

Results: A total of 1198 persons, 455 (38.0%) females and 743 (62.0%) males, participated in this study. While 116 (9.7%), 80 (69.0%) males and 36 (31.0%) females, suffering from diabetes were exempted from OGTT, the remaining 1082 (90.3%), 663 (61.3%) males and 419 (38.7%) females, were screened by OGTT. Among the 663 males, 450 (67.9%) were normal, 155 (23.4%) had impaired glucose tolerance (IGT) and 58 (8.7%) had diabetes. Among the 419 females, 275 (65.6%) were normal, 120 (28.6%) had IGT and 24 (5.7%) had diabetes. Out of 1000 persons without diabetes, 696 (69.6%), 444 (63.8%) with normal glucose tolerance and 252 (36.2%) with IGT had participated in the repeat screening by OGTT after one year. One (0.7%) normal person and 14 (5.5%) with IGT, progressed to diabetes in one year. All had type-2 diabetes and non type-1 diabetes. Of 444 normal persons 34 (7.7%) developed IGT during one year.

Conclusions: The prevalence of 9.7% and 7.7% for known and newly detected type-2 diabetes respectively and the annual incidence of 2.2% indicate the magnitude of impact of diabetes mellitus on this population. Though IGT was found to be a risk factor, factors leading to its progression to diabetic state could not be identified in this study.