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OBJECTIVE--To examine bβ-cell function across a spectrum of glycemia among Asian Indians, a population experiencing type 2 diabetes development at young ages despite low BMI. RESEARCH DESIGN AND METHODS--One-thousand two-hundred sixty-four individuals without known diabetes in the Diabetes Community Lifestyle Improvement Program in Chennai, India, had a 75-g oral glucose tolerance test, with glucose and insulin measured at 0, 30, and 120 min. Type 2 diabetes, isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT), combined impaired fasting glucose and impaired glucose tolerance, and normal glucose tolerance (NGT) were defined by American Diabetes Association guidelines. Measures included insulin resistance and sensitivity (homeostasis model assessment of insulin resistance [HOMA-IR], modified Matsuda Index, 1/fasting insulin) and bβ-cell function (oral disposition index = [Δinsulin0-30/Δ glucose0-30] x [1/fasting insulin]). RESULTS--Mean age was 44.2 years (SD, 9.3) and BMI 27.4 kg/m² (SD, 3.8); 341 individuals had NGT, 672 had iIFG, IGT, or IFG plus IGT, and 251 had diabetes. Patterns of insulin resistance or sensitivity were similar across glycemic categories. With mild dysglycemia, the absolute differences in age- and sex-adjusted oral disposition index (NGT vs. iIFG, 38%; NGT vs. iIGT, 32%) were greater than the differences in HOMA-IR (NGT vs. iIFG, 25%; NGT vs. iIGT, 23%; each, 0.0001). Compared with NGT and adjusted for age, sex, BMI, waist circumference, and family history, the odds of mild dysglycemia were more significant per SD of oral disposition index (iIFG: odds ratio [OR], 0.36; 95% CI, 0.23-0.55; iIGT: OR, 0.37; 95% CI, 0.24-0.56) than per SD of HOMA-IR (iIFG: OR, 1.69; 95% CI, 1.23-2.33; iIGT: OR, 1.53; 95% CI, 1.11-2.11). CONCLUSIONS--Asian Indians with mild dysglycemia have reduced bβ-cell function, regardless of age, adiposity, insulin sensitivity, or family history. Strategies in diabetes prevention should minimize loss of ββ-cell function. [ABSTRACT FROM AUTHOR]

Aims The aim of the present study was to assess carotid intimal media thickness (IMT) in different grades of glucose intolerance and the metabolic syndrome (MS) in Asian Indians, a high-risk group for diabetes and coronary artery disease. Methods Subjects with normal glucose tolerance (NGT) ( n = 1600), impaired glucose tolerance (IGT) ( n = 330), newly diagnosed diabetes (NDD) ( n = 330) and known diabetes (KD) ( n = 1170) were recruited from the Chennai Urban Rural Epidemiology Study (CURES), an ongoing study on a representative population of Chennai (formerly Madras), in southern India. Assessment of carotid IMT was performed using high-resolution B-mode ultrasonography. MS was defined using modified adult treatment parel (ATP) III guidelines. Subjects with self-reported diabetes, hypertension and dyslipidaemia were excluded from the analysis on MS. Results Subjects with glucose intolerance had significantly higher mean carotid IMT values compared with subjects with normal glucose tolerance (NGT 0.69 ± 0.12 mm, IGT 0.75 ± 0.16 mm, NDD 0.79 ± 0.19 mm and KD 0.87 ± 0.24 mm, P < 0.001). Regression analysis showed that there was a linear increase in mean IMT values with increasing severity of glucose intolerance, even after adjusting for age and gender. Mean IMT values were higher in those with MS and increased with increase in number of metabolic abnormalities (subjects without any metabolic abnormality 0.66 ± 0.12 mm, one abnormality 0.67 ± 0.13 mm, two 0.70 ± 0.12 mm, three 0.72 ± 0.12 mm, four 0.77 ± 0.15 mm, five 0.76 ± 0.13 mm). Regression models showed MS to be associated with IMT, even after adjusting for age, gender and presence of diabetes ( P = 0.021). Conclusio In Asian Indians, carotid IMT increases progressively with increasing severity of glucose intolerance and is also associated with the metabolic syndrome, independent of age, gender and presence of diabetes. [ABSTRACT FROM AUTHOR]

Aims: Type 2 diabetes is a heterogeneous disease and may manifest from multiple disease pathways. We examined insulin secretion and insulin resistance across two ethnicities with particularly high risk for diabetes yet with widely different distributions of weight class.Materials and Methods: In this population-based, cross-sectional study, Pima Indians from Southwestern United States (n = 865) and Asian Indians from Chennai, India (n = 2374) had a 75-g oral glucose tolerance test. We analysed differences in plasma glucose, plasma insulin, insulin resistance (HOMA-IR), and insulin secretion (ΔI0-30 /ΔG0-30 ) across categories of body mass index (BMI) and glycemic status per American Diabetes Association criteria.Results: Pima Indians were younger (mean 27.4 ± SD 6.6, Asian: 33.9 ± 6.7 years) and had higher BMI (33.6 ± 8.1, Asian: 25.7 ± 4.9 kg/m2 ). Among normal weight participants (mean BMI: Pima 22.4 SE 0.2; Asian 22.2 SE 0.06 kg/m2 ), fasting glucose was higher in Asian Indians (5.2 vs Pima: 4.8 mmol/L, P = .003), adjusted for age and sex. Pima Indians were three times as insulin resistant as Asian Indians (HOMA-IR: 7.7 SE 0.1, Asian: 2.5 SE 0.07), while Asian Indians had three times less insulin secretion (Pima: 2.8 SE 1.0 vs Asian: 0.9 SE 1.0 pmol/mmol), a pattern evident across age, BMI, and glycemic strata.Conclusions: Metabolic differences between Pima and Asian Indians suggest heterogeneous pathways of type 2 diabetes in the early natural history of disease, with emphasis of insulin resistance in Pima Indians and emphasis of poor insulin secretion in Asian Indians. [ABSTRACT FROM AUTHOR]