Table 1.
Summary results on the randomized controlled trials aimed to prevent type 2 diabetes in people with impaired glucose tolerance or in people at high increased risk for diabetes.
| Study | Country | N, Characteristics | Study Duration | Risk Reduction of T2D with Lifestyle versus Control | Dietary Goals | Changes in Diet When Available | Physical Activity, Goals/Changes | Comment |
|---|---|---|---|---|---|---|---|---|
| Da Qing IGT and Diabetes Study, Pan XR et al. Diabetes Care 1997 [32] | China | In total, 577; all had IGT; 33 health care clinics | 6 yrs | Diet 33%; exercise 47%; diet + exercise 38% | Weight reduction in overweight; calorie restriction | CHO 58–60 E%; protein 11 E%; fat 25–27 E%; total calories decrease 100–240 kcal | Increase, e.g., walking | Randomization by clinic; follow-up data available |
| FDPS, Tuomilehto J et al. N Engl J Med 2001 [33] | Finland | In total, 522; IGT; five centers |
3.2 yrs; median 4 yrs | In total, 58%, weight loss; difference 3.5 and 2.6 kg after 1 and 3 yrs, respectively. | Weight reduction >5%; reduce total and SFA; increase dietary fiber | 3 yr results: energy reduction 204 kcal; CHO increase 3 E%; fat reduction 5 E%; SFA reduction 3 E%; fiber increase 2 g/1000 kcal |
4 h/wk, sedentary people at yr 3: 17% vs. 29% for intervention and control groups, respectively | Individual dietary data and long-term follow-up data available |
| DPP, Knowler WC et al. New Engl J Med 2002 [34] | USA | In total, 3234; IGT; 27 centers |
2.8 yrs | Lifestyle 58%; Metformin 31%; weight loss at yr 1: −5.6 vs. −0.1 kg for intervention vs. control, respectively. | NCEP Step 1; weight loss goal 7% | Energy intake reduction 450 vs. 249 kcal and fat intake reduction 6.6 vs. 0.8 E% for intervention and control, respectively. | 150 min/wk | Follow-up data available |
| Japanese trial in IGT males, Kosaka K et al. Diabetes Res Clin Pract 2005 [36] | Japan | In total, 458 IGT; 356 in control, 102 in intervention, OGTT (100 g glucose dose) | 4 yrs | Incidence of T2D 3.0% vs. 9.3%; risk reduction 67.4%; weight loss −2.18 kg | BMI goal 22 kg/m2; increase vegetables; reduce food intake by 10%; fat < 50 g/d; alcohol restriction | Not reported | 30–40 min walking/d | Normal and overweight men |
| IDPP-1, Ramachandran A et al. Diabetologia 2006 [37] | India | In total, 531; IGT; lifestyle 133; metformin 133; lifestyle-plus-metformin 129; control 136 | 30 months | Lifestyle 28.5%; Metformin 26.4%; lifestyle-plus-Metformin 28.2%; no change in body weight | Reduce total calories, refined CHO, fat and sugar; increase high fiber-rich foods | Dietary adherence increased in Intervention groups | Walking 30 min a day | |
| Lifestyle intervention on metabolic syndrome. Bo S, J Gen Intern Med 2007 [38], Bo S et al. Am J Clin Nutr 2009 [39] | Italy | In total, 375 with dysmetabolism; 169 intervention; 166 control; focus on metabolic syndrome | 1 yr, | Risk reduction for T2D 77%, (OR 0.23; 95% CI 0.06–0.85) at year 1. | General recommendations for lose weight and decrease SFA and increase PUFA and fiber | Body weight minus 0.75 vs. plus 1.63 kg; total calories minus 74.6 vs. 43.7 kcal; fat minus 2.64 E%; SFA minus 1.97 E%; CHO 2.14 E%; prot 1.7 E%; NS for control | Increase | 4 yrs diabetes incidence 5.4% vs. 10.2% in intervention and control groups, respectively |
| EDIPS-Newcastle, Penn L. BMC Public Health 2009 [40] | UK | In total, 102; IGT; 51 in intervention and control, respectively | 3 yrs | Diabetes incidence 5% vs. 11, 1% yr. body weight change −2.5 kg | Like in FDPS, decrease fat and SFA; increase fiber; body weight reduction | Not reported | Like in FDPS | Sustained beneficial changes in lifestyles predicted better outcome |
IGT = impaired glucose tolerance based on OGTT, CHO = carbohydrates, prot = protein, SFA = saturated fatty acids, PUFA = polyunsaturated fatty acids, intervention = intervention group, control = control group, minus = reduction from baseline, NA = not available, and NS = not significant, LSM = lifestyle modification, Met = Metformin. Da Qing IGT: The Da Qing IGT and Diabetes Study; FDPS: Finnish Diabetes Prevention Study; DPP: The Diabetes Prevention Program; IDDP-1: The Indian Diabetes Prevention Programme; EDIPS: European Diabetes Prevention Study; LSM: lifestyle modification; Met: metformin; yrs: years; IGT: Impaired glucose tolerance.