This chapter reviews the results of important studies on the prevention of type 2 diabetes (DM2) and its long term complications in people with impaired glucose tolerance (IGT). Randomized controlled trials of lifestyle interventions focusing on diet, weight reduction and increased physical exercise have resulted in relative risk reductions (RR’s) for progression to diabetes ranging from 28.5 to 58 % during the active phases of the study and continued RR’s for the development of DM2 during long-term follow-up. Lifestyle interventions have also resulted in sustained improvents in multiple cardiovascular risk factors including improvements in blood pressure, serum lipids and the metabolic syndrome. In one of the longest studies to date, the DA Qing study, there was aslo a significant reduction in cardiovascular mortality after 23 years of follow-up.
Several medication trials are also reviewed. The risk reductions ranged from 25 to 79 % depending on the agent used. However, no long-term benefits from any of the study medications have been observed after discontinuation of theraphy. Finally, the results of weight loss therapies, including bariatric surgery, are discussed and general recommendations for patient screening and management are provided.