Prevalence of vitamin D deficiency in urban south Indians with different grades of glucose tolerance.

The present study assessed the prevalence of vitamin D deficiency in an urban south Indian population in individuals with different grades of glucose tolerance. A total of 1500 individuals (900 normal glucose tolerance (NGT), 300 prediabetes and 300 with type 2 diabetes mellitus (T2DM)) who were not on vitamin D supplementation were randomly selected from the Chennai Urban Rural Epidemiological Study follow-up study. Anthropometric, clinical examination and biochemical investigations (25-hydroxyvitamin D (25(OH)D), insulin, glycated Hb (HbA1c) and serum lipids) were measured. Vitamin D deficiency was defined as serum 25(OH)D < 20·0 ng/ml, insufficiency as 20-29·9 ng/ml and sufficiency as ≥30 ng/ml. Of the 1500 individuals studied, 45 % were males and the mean age was 46 (sd 12) years. Vitamin D levels lowered with increasing degrees of glucose tolerance (NGT: 21 (sd 11); prediabetes: 19 (sd 10); T2DM: 18 (sd 11) ng/ml, P < 0·001). The overall prevalence of vitamin D deficiency was 55 % and was significantly higher among individuals with T2DM (63 %) followed by prediabetes (58 %) and NGT (51 %) (Pfor trend < 0·001). Women had 1·6 times the risk of vitamin D deficiency compared with men (unadjusted OR 1·6 (95 % CI 1·3, 2·0) and adjusted OR 1·6 (95 % CI 1·2, 1·9)). However, there was no increasing trend observed with increasing age. The prevalence of abdominal obesity (66 v. 49 %), generalised obesity (80 v. 64 %), the metabolic syndrome (45 v. 37 %) and insulin resistance (38 v. 27 %) was significantly higher in those with vitamin D deficiency compared with those without. This study shows that vitamin D deficiency is highly prevalent in this urban south Indian population and was higher among individuals with T2DM and prediabetes compared with those with NGT.

Association of TCF7L2 Polymorphism with Diabetic Nephropathy in the South Indian Population.

The transcription factor 7-like 2 (TCF7L2) gene plays a significant role in the development of type 2 diabetes and diabetic nephropathy. The aim of this study was to investigate the association of TCF7L2 rs12255372 (G/T)polymorphism with type 2 diabetic nephropathy in the South Indian population. A total of 2102 subjects, 927 normal glucose tolerant (NGT) subjects, 598 type 2 diabetic subjects without nephropathy (DM), and 577 type 2 diabetic subjects with nephropathy (DN) were genotyped by MassARRAY. As compared to the NGT group, the odds ratio (adjusted for age, sex, BMI, HbA1c, and systolic BP) computed for the GT/TT genotype taking the GG genotype as reference was found to be 2.02 (95% CI: 1.16-3.51, p = 0.013) for DN and 1.94 (95% CI: 1.36-2.78, p = 0.0002) for DM. The genotype frequency was not significantly different between the DM and DN groups. In conclusion, the rs12255372 polymorphism in the TCF7L2 gene is associated with type 2 diabetes and DN but its association with DN is mediated through diabetes.

Diabetes in Asian Indians-How much is preventable? Ten-year follow-up of the Chennai Urban Rural Epidemiology Study (CURES-142).

We sought to evaluate the contribution of various modifiable risk factors to the partial population attributable risk (PARp) for diabetes in an Asian Indian population. Of a cohort of 3589 individuals, representative of Chennai, India, followed up after a period of ten years, we analyzed data from 1376 individuals who were free of diabetes at baseline. A diet risk score was computed incorporating intake of refined cereals, fruits and vegetables, dairy products, and monounsaturated fatty acid. Abdominal obesity was found to contribute the most to incident diabetes [Relative Risk (RR) 1.63(95%CI 1.21-2.20)]; (PARp 41.1% (95%CI 28.1-52.6)]. The risk for diabetes increased with increasing quartiles of the diet risk score [highest quartile RR 2.14(95% CI 1.26-3.63)] and time spent viewing television [(RR 1.84(95%CI 1.36-2.49] and sitting [(RR 2.09(95%CI 1.42-3.05)]. The combination of five risk factors (obesity, physical inactivity, unfavorable diet risk score, hypertriglyceridemia and low HDL cholesterol) could explain 80.7% of all incident diabetes (95%CI 53.8-92.7). Modifying these easily identifiable risk factors could therefore prevent the majority of cases of incident diabetes in the Asian Indian population. Translation of these findings into public health practice will go a long way in arresting the progress of the diabetes epidemic in this region.