Comparison of an Energy-Reduced Mediterranean Diet and Physical Activity Versus an Ad Libitum Mediterranean Diet in the Prevention of Type 2 Diabetes : A Secondary Analysis of a Randomized Controlled Trial.

Abstract

Limited research has been done to evaluate the combined effect of energy reduction, Mediterranean diet (MedDiet), and physical activity on type 2 diabetes incidence. To evaluate whether an energy-reduced MedDiet (erMedDiet) plus physical activity reduces diabetes incidence compared with a standard MedDiet. Prespecified secondary outcome analysis in the PREDIMED (Prevención con Dieta Mediterránea)-Plus randomized, single-blinded, controlled trial. (ISRCTN Registry: ISRCTN89898870). 23 centers across Spain. 4746 adults aged 55 to 75 years with metabolic syndrome and overweight or obesity, without prior cardiovascular disease or diabetes. Participants were randomly assigned 1:1 to an intervention group receiving an erMedDiet (planned reduction of 600 kcal per day), increased physical activity, and behavioral strategies for reducing weight, or a control group receiving ad libitum MedDiet advice. Diabetes incidence was based on the American Diabetes Association criteria. Anthropometric measurements were obtained annually. Cox regression models were used to assess the intervention effect. The 6-year absolute risk was 12.0% (95% CI, 11.9% to 12.1%) in the control group (349 cases) and 9.5% (CI, 9.4% to 9.5%) in the intervention group (280 cases). Over a median 6-year follow-up, diabetes incidence was 31% (CI, 18% to 41%) relatively lower in the intervention group compared with the control group, with an absolute risk reduction of -2.6 cases (CI, -2.7 to -2.4) per 1000 person-years. The intervention group attained better adherence to the erMedDiet, higher physical activity levels, and greater reductions in body weight and waist circumference. Secondary outcome, single-blinded design, and self-reported dietary adherence. An intensive intervention with the MedDiet adding caloric reduction, physical activity, and modest weight loss was more effective than only an ad libitum MedDiet in reducing diabetes incidence in overweight/obese persons with metabolic syndrome. Instituto de Salud Carlos III.