Effect of nutritional intervention on prevalence of metabolic syndrome and heart disease risk factors among urban Tehranians: Tehran Lipid and Glucose Study (TLGS)

Heart disease is the primary cause of mortality in most countries. Different approaches have been designed for the prevention of heart disease risk factors, of which nutritional interventions is a main one. In the Tehran Lipid and Glucose Study, a sub-sample of 1474 subjects, were selected as cases for dietary assessment and implementation of nutritional interventions. After a 3. 8 year follow up, data were collected in both the intervention and case groups. Three hundred and sixteen subjects, aged 20 and over, that were not pregnant and did not use any hypoglycemic agents, lipid-lowering and anti-hypertensive prescription medications were enrolled for the study they were divided into controls (183 subjects) and cases (133 subjects). Mean energy intakes and macronutrients, were measured and compared within the two groups, using the paired t- test and ANCOVA was used between the two groups after controlling for age, sex, and baseline variables. Chi square and Mantel-Haenszel tests were performed to assess the prevalence of risk factors and metabolic syndrome between and within groups. McNemar test was used to assess the change of risk factors before and after intervention. Mean energy, carbohydrate and fat intake decreased and cholesterol intake increased significantly in both groups. The prevalence of low HDL and central obesity increased in controls whereas hypercholesterolemia and high LDL cholesterol decreased significantly in the cases. The prevalence of high LDL decreased in cases as compared to the controls, with and without controlling for age, sex, and BMI. Pre- and post intervention evaluations showed improvement in hypercholesterolemia (p<0. 01) and high LDL (p<0. 01) in cases vs controls, whereas lesser improvement were seen in low HDL (p<0. 01) and central obesity (p<0. 01) in controls vs cases. The present study shows the effectiveness of nutritional interventions in curtailing and improving some risk factors of heart disease.