Strategies for the prevention of type 2 diabetes.

Type 2 diabetes is a common chronic disease affecting more than 100 millions of people world-wide, and is a major cause of premature morbidity and mortality. Macrovascular disease and its risk factors are often already present in individuals at risk for type 2 diabetes, and some of the risk factors for the development of type 2 diabetes, such as obesity, physical inactivity, and high-fat diet, can potentially be modified. Because some of the metabolic abnormalities, such as insulin resistance or impaired glucose tolerance, that indicate a risk for diabetes can be improved by lifestyle modification and drug treatment, strategies for the prevention of type 2 diabetes appear to be necessary for affected individuals. Several clinical trials have addressed the hypothesis that type 2 diabetes can be prevented by dietary modification, physical activity, or drug treatment. Although some of these studies indicate a protective effect of these measures against the development of type 2 diabetes in people at risk, many of their conclusions are limited with respect to randomisation, sample size, or intensity of the intervention. In the large prospective Da Qing study (1997), both dietary and physical activity interventions reduced the incidence of type 2 diabetes considerably in a Chinese population. Whether this is also achievable in other ethnic populations at high risk for developing type 2 diabetes, and whether additional pharmacological measures are useful, is currently under investigation.