Effect of olive oil enriched in oleanolic acid on the incidence of type 2 diabetes mellitus in patients with pre-diabetes

INTERVENTION: At each visit, patients will receive the oil for their consumption over 3 months. In both of the groups every 3 months, a visit will be made to provide a customised dietetic intervention. The amount of oil to consume is 55.5 ml/day, taken raw. In the case of the oil enriched with oleanolic acid, this would contribute 40 mg/day to the participants diet. Added 9/11/09: 1. Baseline variables (BV) and patient data (PD) measured at visit 0 (baseline visit): 1.1. History of type 2 diabetes mellitus in first‐degree relative. 1.2. Time developments of prediabetes. 1.3. History of hypertension, ischemic heart disease, cerebrovascular disease and peripheral arterial disease. 1.4. Smoking status and alcohol consumption 1.5. Physical Exercise. 2. Lifestyle information also assessed at baseline CONDITION: Type 2 diabetes mellitus ; Nutritional, Metabolic, Endocrine ; Non‐insulin‐dependent diabetes mellitus PRIMARY OUTCOME: Incidence of diabetes, diagnosed according to basal blood glucose or oral glucose overload, conducted every 6 months or 12 months respectively after entry into the study, according to recent criteria of the American Diabetes Association (ADA) (a fasting plasma glucose = 126 mg/dl or symptoms of hyperglycaemia and casual plasma glucose = 200 mg/dl or a plasma glucose value at 2 hours after an oral overload of 75 g of glucose = 200 mg/dl. In the absence of unequivocal hyperglycaemia, these criteria should be confirmed by repeating the test on a different day.) SECONDARY OUTCOME: 1. Body mass index (BMI = weight in kilograms divided by the square of height in metres) measured at baseline; 2. Waist circumference (abdominal perimeter in cm) ; 3. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) ; 4. Pulse pressure (SBP ‐ DBP) ; 5. Lipid profile: ; 5.1. Total cholesterol (mg/dl) ; 5.2. Triglycerides (mg/dl) ; 5.3. High density lipoprotein (HDL) cholesterol (mg/dl) ; 5.4. Low density lipoprotein (LDL) cholesterol (mg/dl) ; 6. Fasting plasma glucose (mg/dl) ; 7. Insulin (IU/ml) ; 8. HOMA index (Homeostasis Model Assessment): uU/ml x mmol/L/22.5 (HOMA =[glucose (millimoles per litre) x insulin (microunits per millilitre)]/22.5) was used as a measure of insulin resistance (IR); 9. Haemoglobin A1c (HbA1c) (%) ; 10. Plasma glucose at 2 hours after oral glucose overload (75 g) measured at months 12 and 24 (and at baseline where applicable); ; Added 09/11/09:; 11. Personal interview (PI) carried out at baseline and months 3, 6, 9, 12, 15, 18, 21 and 24 to assess: ; 11.1. hypocaloric diet ; 11.2. physical exercise habits; 11.3. toxic habits; 12. Assessment of Compliance (AC) at months 3, 6, 9, 12, 15, 18, 21 and 24; ; Physical Examination (PE) (pts. 2‐4 above) measured at baseline, months 3, 6, 9, 12, 15, 18, 21, and 24.; Laboratory variables monitored (LVM) (pts. 5‐9 above) measured at baseline, months 6, 12, 18 and 24. INCLUSION CRITERIA: Current information as of 09/11/09: 1. Men or women with an age range between 30 and 80 years 2. Body mass index = 25 kg/m^2 and < 40 kg/m^2 3. Acceptance to participate in the study and signed the corresponding informed consent Initial information at time of registration: 1. Men or women with an age range between 30 and 80 years 2. Body mass index = 25 kg/m^2 3. Acceptance to participate in the study and signed the corresponding informed consent