Association of glycaemic index and glycaemic load with metabolic syndrome in an Iranian adult population: Isfahan Healthy Heart Program

Aim: There is controversy around the clinical effects of the dietary glycaemic index (GI) and glycaemic load (GL) on cardiovascular diseases risk factors such as metabolic syndrome (MetS). So, the present study was performed to evaluate the relationship between GI or GL and metabolic syndrome in an Iranian adult population in 2007. Methods: The study was based on data from a sub-sample of the Isfahan Healthy Heart Program (IHHP), collected across three cities in central Iran, in the year 2007. This was a cross-sectional survey of 1618 randomly selected adults aged >= 19 years. Nutritional assessment was conducted by a single 24-hour recall questionnaire. Fasting serum lipids, anthropometric indicators and blood pressure were measured by standard methods. Analysis of covariance was used to compare metabolic syndrome components according to energy-adjusted GI and GL levels. To expose the effect of potential confounders, hierarchical logistic regression models were utilised to determine adjusted odds ratios (OR) and 95% CI. Results: After adjustment for age, gender, body mass index and energy intake, high GI was found to be significantly associated with MetS (OR 95% CI) (1.46 (1.01-2.12)). This was attenuated marginally by excluding the confounding effects of dietary fibre intake (1.29 (1.01-1.74)). All hierarchical models illustrated no significant association between energy-adjusted GL and the risk of MetS adjusted for confounders. Conclusions: There is a positive relationship between dietary GI, but not GL, and the presence of MetS after adjustment for potential confounders. However, studies with long duration of follow up and experimental studies are still required to confirm this relationship.