Mediterranean dietary patterns and risk of type 2 diabetes in the Islamic Republic of Iran

Abstract

Background: More than 1% of urban Iranians aged >20 years develop type 2 diabetes annually. A major contributing factor is overweight due to energy imbalance and poor quality diet. Even though there are reports on the beneficial effects of some isolated foods on glucose metabolism, researchers are increasingly focusing on dietary patterns versus single foods. Aims: The aim of this study was to evaluate the association between adherence to a Mediterranean diet and risk of type 2 diabetes. Methods: The current study was a case–control study nested in the cohort of the Tehran Glucose and Lipid Study. Among participants who met the study criteria, 187 incident cases of diabetes were identified and matched with 374 healthy controls according to sex, age, date of data collection, and previous history of lifestyle intervention. Results: In the highest Mediterranean Diet Scale (MDS) category there were higher intakes of energy, fibre, glycaemic load, carbohydrate, total fat, and olive oil. However saturated fatty acid and monounsaturated fatty acid intakes decreased in higher MDS categories. The multiple adjusted odds ratios (ORs) for type 2 diabetes among individuals with medium (score 3–4) and high (score 5–8) adherence to MDS were 0.79 (95% CI:0.38–1.65) and 0.93 (95% CI:0.44–1.96), respectively, compared to individuals with low adherence (score 0–3). Conclusion: Adherence to the Mediterranean dietary pattern was not associated with type 2 diabetes. Increased rates of type 2 diabetes in the Islamic Republic of Iran might be accounted for by the cultural and traditional differences between the Iranian and the Mediterranean dietary patterns.