Prevalence of depression in relation to glucose intolerance in urban South Indians- The Chennai Urban Rural Epidemiology Study (CURES-76)

Background: This study investigated the association between depression and glucose intolerance in urban residents of southern India. Methods: Subjects were recruited from the Chennai Urban Rural Epidemiology Study, carried out on a representative sample of 26,001 subjects recruited from Chennai city in southern India. Subjects with known diabetes were excluded (n=1,498). Of the remaining 24,503 subjects, fasting capillary blood glucose (FBG) estimation were available for 23,787 subjects (response rate, 97.1%) in whom depression was assessed using a validated instrument, the Patient Health Questionnaire-12. Subjects with FBG values ≥126mg/dL were termed as subjects with newly diagnosed diabetes (NDD), those with values between 100 and 125mg/dL as having impaired fasting glucose (IFG), and those with >100mg/dL as having normal fasting glucose (NFG). Results: The overall prevalence of depression was 14.3% (3391 of 23,787 subjects), and an increasing prevalence of depression was seen with increasing grades of glucose intolerance: NFG (13.1%), IFG (15.7%), and NDD (19.7%) (trend χ2=57.1, P<0.001). The prevalence of depression was higher in females at all grades of glucose intolerance. Risk for depression was higher among NDD subjects compared to NFG subjects (odds ratio=1.12, 95% confidence interval 1.03-1.22, P=0.01) and IFG subjects (odds ratio 1.21, 95% confidence interval 1.02-1.44, P=0.03) and also for IFG compared to NFG subjects (odds ratio=1.12, 95% confidence interval 1.02-1.21, P=0.01) after adjusting for age, gender, body mass index, hypertension, and socioeconomic status. Conclusion: The prevalence of depression increases with increasing grades of glucose intolerance and is highest among those with diabetes