The following strategies have been assessed, without a positive result;
Diabetes Preventive Trial-1 (DPT-1). In the USA, relatives of diabetics who were predicted to have at least a 26% 5 year risk of developing diabetes were studied. After screening 104 thousand relatives 700 people were randomised to two studies. High risk people (risk greater than 50%) were randomised to either twice daily insulin injections or observation. Moderate risk people (risk 26%-50%) were randomised to oral insulin or placebo. Unfortunately both the oral and injecting insulin arms of the trial have shown no benefit.
Oral nicotinamide (a type of vitamin B) was compared to placebo in 18 countries in a multicentre european trial. Again there was no benefit.