Glucose indices, health behaviours and incidence of diabetes in Australia: the AusDiab study.

Abstract

Objective: This national, population-based study reports diabetes incidence based on OGTT and identifies risk factors for diabetes in Australians.

Research Design and Methods: The Australian Diabetes, Obesity and Lifestyle Study followed up 5842 participants over five years. Normal glycemia (NG), impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and diabetes were defined using the WHO criteria.

Results: Age-standardized annual incidence of diabetes for men and women was 0.8% (95% CI, 0.6–0.9), and 0.7% (0.6–0.9), respectively. The annual incidence was 0.2% (0.2–0.3), 2.6% (1.8–3.4) and 3.5% (2.9–4.2) among those with NG, IFG, and IGT, respectively at baseline. Among those with IFG, the incidence was significantly higher in women (4.0 vs. 2.0%), while among those with IGT, it was significantly higher in men (4.4 vs. 2.9%). Using multivariate logistic regression, hypertension (OR 1.64, 95% CI 1.17–2.28), hypertriglyceridemia (OR 1.46, 1.04–2.02), fasting plasma glucose (OR per one SD 5.24, 3.98–6.91), waist circumference (OR per one SD 1.26, 1.08–1.48), smoking (OR 1.70, 1.10–2.62), physical inactivity (OR 1.56, 1.12–2.16), and low education level (OR 1.85, 1.03–3.31), were associated with incident diabetes. In age–sex adjusted models, HbA_1c was a predictor of diabetes in the whole population, in those with NG, and in those with IGT or IFG.

Conclusion: Diabetes incidence is 10-20 times greater in those with IGT or IFG than those with NG. Measures of glycemia, HbA_1c, metabolic syndrome components, education level, smoking, and physical inactivity are risk factors for diabetes.