Type 2 diabetes in southern Kerala: Variation in prevalence among geographic divisions within a region

Background. Numerous surveys carried out in India report the high prevalenc e of type 2 diabetes. Such studies have not included the population of Kera la. We estimated the prevalence of type 2 diabetes mellitus in Neyyattinkar a taluk, Thiruvananthapuram district, Kerala state. Methods. All panchayat wards in the taluk were grouped into urban, highland , midland or coastal, and one ward from each stratum was randomly selected for the study. All households were listed and adults, 20 years or older, sc reened for high ( > 110 mg/dl) random blood sugar (RBS) by a glucometer tes t. Those with high RES were reassessed by a fasting oral glucose tolerance test (OGTT), consisting of initial examination of venous blood for fasting plasma glucose (FPG) values, administration of 75 g of glucose dissolved in distilled water, and examination of venous blood for postprandial plasma g lucose (PPPG) exactly 2 hours after the administration of glucose. Diabetes was diagnosed according to the World Health Organization criteria as eithe r FPG > 139 mg/dl, or PPPG > 199 mg/ di, or both. Impaired glucose toleranc e (IGT) was diagnosed if PPPG was 140-199 mg/dl. Results. Out of 4988 eligible subjects, 3899 were available for the study, a response rate of 78.2%. Response was highest in the highland area (86.2%) , and lowest in the coastal area (73.6%). The overall crude prevalence rate of type 2 diabetes was 5.9%. It was highest in the urban (12.4%), followed by midland (8.1%), highland (5.8%), and coastal (2.5%) regions. Ageing was associated with greater prevalence of type 2 diabetes in all regions and b oth sexes. Women showed a higher prevalence in the highland and coastal are as and men in the urban and midland areas. When compared to a population wi th standard age structure suggested by the World Health Organization for in ternational comparisons, prevalence in the age group 30-64 years was found to be 16.9% in the urban, 10.1% in the midland, 6.8% in the highland and 3. 6% in the coastal regions, respectively. Overall age-adjusted prevalence of type 2 diabetes in 30-64-year-olds in Neyyattinkara was 9.2% among men, 7. 4% among women, and 8.2% for all persons. There was not much difference in prevalence if the American Diabetes Association criteria for diagnosis were used. The prevalence of impaired glucose tolerance was fairly low in this population. Out of 229 diabetics in the sample, 175 (76.5%) were already di agnosed and under treatment, while our survey identified 54 new diabetics ( 23.5%). Conclusion. Though prevalence of type 2 diabetes is high in this population , the detection rate is also high. However, impaired fasting glucose and im paired glucose tolerance are low. The reasons for this need to be elucidate d.