Iranian Journal of

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Background: Diabetes type 1 is an autoimmune disease that is associated with other autoimmune disorders like Hashimoto thyroiditis. The purpose of this study was to determine the prevalence of autoimmune thyroid disease (ATD) in type 1 diabetic patients in the south of Iran (Bandar Abbas).
Methods: A cross-sectional study, was conducted 48 type 1 diabetics and 41 age and sex matched healthy controls were evaluated for the presence of ATD. Blood sample were collected from all of the subjects for the measurement of thyroid autoantobodies [anti thyroid peroxidase (anti-TPO) and anti thyroglobulin (anti-TG)], T3, T4, TSH, RT3U and HbA1c.
Results: Prevalence of positive anti-TPO and anti-TG was 29 % and 29% respectively in diabetic patients and 2% and 7% respectively in control group (P<0.05). The prevalence of ATD (positive anti TPO or anti TG) in diabetic patients and control subjects was 35% and 7% respectively (P<0.05). The prevalence of positive anti TPO and anti TG was higher in girls. There was no association between the prevalence of positive autoantibody and duration or age of onset of diabetes. 17.6% of diabetic patients with positive autoantibody had thyroid dysfunction (subclinical hypothyroidism and hyperthyroidism).
Conclusion: Regarding high prevalence of ATD in type 1 diabetic patients in Bandar Abbas (approximately 1 out of 3 patients), screening for ATD and thyroid dysfunction is recommended for all type 1 diabetic patiens and in those with positive autoantibody consecutively.

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Background: a variety of studies have noted seasonal variation in blood lipid levels, yet the mechanism for this phenomenon has not been clear. This leads to significant difference in prevalence of lipid disorders in different seasons.
Methods: A cross sectional study conducted on 6894 individuals (2890 men and 4004 women) aged 20-64 years who participated in the 1st phase of Tehran Lipid and Glucose study from March 1999 to September 2001. The mean level of plasma lipid values was compared between seasons by ANCOVA after adjustment for age, physical activity, smoking, BMI and waist-to-hip ratio. The sex specific prevalence of lipid disorders in summer and winter was calculated.
Results: 58% of participants were women. The mean age of men and women was 38.3±11.3 and 39.4±11.6 respectively (P=0.13). There was a significant seasonal variation in serum total cholesterol, LDL-C and HDL-C in men (P<0.05) with a peak in winter and a trough in summer (P<0.05). In women, only triglyceride levels showed significant seasonal variation characterized by increase in summer and decrease in winter (P<0.05). In men, there was 26.2% increase in prevalence of hypercholesterolemia (>240 mg/dl) in winter compared to summer (P<0.05). The corresponding increase in level of high risk LDL-C (≥160 mg/dl) was 26.7% and 24.9 % in men and women respectively (P<0.05). There was 23.8% decrease in the prevalence of hypertriglyceridemia (>200 mg/dl) in winter compared to summer in women (P<0.001).
Conclusion: This study confirms seasonal variation in blood lipid levels and suggests greater amplitude in seasonal variability in men than women. On the other hand, the increase in the prevalence of high risk LDL-C in both genders in winter should be considered in patients screening and follow-up strategies.

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Background: To evaluate the role of lipid markers including total cholesterol (TC), LDL-C and HDL-C vs. lipid indices (TC/HDL-C, LDL-C/HDL-C and non-HDL-C) as short term predictors of cardiovascular outcomes in adults over 30 years.
Methods: As a nested case and control study, there were 207 CVD events among participants of Tehran Lipid and Glucose Study (TLGS) documented during 3 years of follow-up. Those cases that were free of CVD at baseline (132 subjects) were matched to 264 controls for age and sex. In all subjects, demographic and clinical data including blood pressure and anthropometric measurements as well as serum lipids, fasting and 2-hour glucose were available from the database of the TLGS. We estimated the relative risk (RR) for each lipid parameter in a multiple stepwise regression model after adjustment for family history of premature CHD, smoking, systolic and diastolic blood pressure, fasting and 2-hour plasma glucose and waist-to-hip ratio.
Results: The RRs associated with an increase of ≈1 SD of independent lipid predictors in the multivariate model were as follow: total cholesterol (RR=1.6 [1.2-2.0], SD= 1.3 mmol/L), LDL-C (RR=1.5 [1.1-2.0], SD= 1 mmol/L), non-HDL-C (RR=1.6 [1.2-2.1], SD= 1.2 mmol/L) and cholesterol/HDL-C (RR= 1.5 [1.1-2.0], SD= 1.8). The comparing of these four independent variables with ROC curve analysis showed that there was no significant difference in their predictive power for cardiovascular outcome. There was no association between HDL-C, triglyceride and LDL-C/HDL-C and CVD outcome in multivariate analysis.
Conclusion: This study showed that TC, LDL-C, non-HDL-C and TC/HDL-C have similar predictive values for short term prediction of CVD outcome. It seems TC may be a reasonable choice for short term prediction of CVD outcome, because of lower cost.

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Background: The aim of this study was to determine the best Anthropometric indices for prediction of the risk of type 2 Diabetes in lower and higher 60 years old population in Tehran.
Methods: As a prospective study among 4479 non-diabetic men and women over 20 years from the participants of Tehran Lipid and Glucose Study (TLGS) who had complete data of blood pressure, plasma glucose in the fasting state and 2 hours after ingestion of 75 g glucose (2-hPG) as well as fasting serum lipids, anthropometric measurement including body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and demographic data at baseline and were followed for a mean duration of 3.6 years. Subjects reevaluated for measurement of fasting Glucose and 2-hPG at follow-up. Diabetes and its associated risk factors were defined according to the ADA criteria. Different measurements of general and central obesity were defined based on the WHO criteria. Logistic regression analysis with stepwise conditional method was used to estimate the Odds Ratio (OR) with 95% CI. Results: A total of 166 new cases of type 2 diabetes (3.7%) were diagnosed during 3.6 years of follow-up, with an approximately one percent per year incidence rate (men=3.7% and women =3.7%, P= 0.95). Diabetic subjects of follow-up were significantly more obese than nondiabetics considering their BMI, WC and WHR. In subjects aged< 60 years high WC was a predictor of diabetes only in model 1 and 2, while general obesity and high WHR predicted diabetes risk in all the 3 models. In these 3 models the OR of general obesity were 5.3(2.9-9.5), 3.4(1.8-6.3), 2.4(1.1-5.1) and the OR of high WHR were 3.5(2.1-5.8), 3.4(1.4-5.8) and 2.6(1.3-4.9), respectively. In subjects aged≥ 60 years general obesity predicted diabetes only in models 1 and 2, while high WHR was a predictor of diabetes risk only in model 1. In this age group, high WC predicted diabetes in all models 1, 2, 3 with the OR of 4.6 (2.3-4.1), 4.5 (2.3-8.9) and 3.8 (1.8-7.7), respectively.
Conclusion: General obesity and high WHR in young Iranian subjects (< 60years) and high WC in older ones (≥ 60 years) are the important anthropometric indices for prediction of type 2 diabetes. Age should be considered when using different anthropometric indices for predicting the risk of type 2 diabetes.

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Background: The risk of metabolic risk factors increases in Middle-Eastern adults within the normal limits of BMI. There is a report that 30.1% of the Iranian population had metabolic syndrome but no reports on the prevalence of this syndrome among individuals within the various BMI categories are available. The present study estimates the prevalence of metabolic syndrome in adult population with normal levels of BMI (18.5-24.9 kg/m2). Methods: In this population-based cross-sectional study, a representative sample of 3444 subjects (1737 males and 1707 females) aged≥20 years with normal body mass index (BMI= 18.5-24.9 kg/m2 for both genders) were included. Demographic data were collected anthropometric indices and blood pressure were measured according to standard protocol. Biochemical analysis was conducted on fasting blood samples. The metabolic syndrome was defined according to the ATP Ш guidelines as the presence of three or more of the metabolic factors. Means and proportions, and multivariate odds ratios that quantify the association between metabolic syndrome and normal BMI quartiles, controlling for age, physical activity, smoking and education were presented. Results: The overall prevalence of the metabolic syndrome in normal weight men and women were 9.9% (CI 95%: 8.49-11.30) and 11.0% (CI 95%: 9.5-12.4, P=0.2), respectively. Men had slightly lower BMI than women (22.4±1.8 vs. 22.5±1.7 kg/m2, P<0.001), while their WC was higher (79.8±6.6 vs.79.3±7.7 cm, P<0.001). The prevalence of high WC and low HDL was higher in women, while high blood pressure, high triglyceride levels and having at least two metabolic risk factors were more prevalent in men. Individuals at the highest category of normal BMI had significantly higher odds for being at risk for metabolic syndrome compared to those at first category (OR 5.21 for men and 2.15 for women). There was a significant increasing trend in odds for having all the metabolic syndrome components except for high FBS and high WC in men. Women revealed a similar increasing trend except for high FBS across normal BMI quartiles.
Conclusion: Normal weights Iranians have excess cardiovascular risk. Therefore interventions for prevention of diabetes and cardiovascular disease could be considered in normal weight population. On the other hand, the cut-points of BMI, suggested by WHO, may be inappropriate for the Iranian adult population.

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Background: The aim of this study was to determine the level of agreement between the impaired fasting glucose (IFG) and abnormal glucose tolerance before and after application of the new IFG definition and to evaluate the impact of adding common clinical data on this agreement.
Methods: A cross sectional population based study was carried out in an Iranian urban population which enrolled 8766 men and women over 20 years. Fasting and 2-hour plasma glucose were measured in all subjects excluding those with previously diagnosed diabetes and fasting plasma glucose ≥126 mg/dl. The diagnostic parameters and kappa coefficient between the previous and revised definitions of IFG for detecting impaired glucose tolerance (IGT) and dysglycemia (IGT and diabetes) were calculated. Logistic regression and ROC curve analysis were used to determine the independent clinical risk factors and their optimal cut-points associated with IGT and dysglycemia. Results: After using the new criteria, sensitivity of IFG for detecting IGT or dysglycemia increased but specificity and positive likelihood ratio (LR+) decreased and the κ slightly improved (0.16 to 0.29 for IGT and 0.24 to 0.35 for dysglycemia). Adding the clinical data to the revised criteria considerably improved the agreement between IFG with IGT and dysglycemia (κ increased from 0.286 to 0.470 for IGT and from 0.354 to 0.574 for dysglycemia). This also increased the LR+ from 3.86 to 14.5 and from 4.46 to 17.4 respectively for detecting IGT or dysglycemia.
Conclusion: The new IFG definition in combination with common clinical risk factors most likely predicts IGT and dysglycemia.

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In April 2005, the International Diabetes Federation (IDF) has formulated a new worldwide definition of the metabolic syndrome in a global consensus statement built on earlier WHO, the ATPIII definitions. The aim of this study was to estimate the prevalence of this syndrome using the IDF definition among Iranian adults and to compare it with the prevalence estimated using the two other definitions. 

Methods: The prevalence of the MES was determined according to the three different definitions in 10368 men and women aged≥20 years participated in the cross-sectional phase of the Tehran Lipid and Glucose Study (TLGS). To assess the degree of agreement between different MES definitions, the k test was used. 

Results: The prevalence of MES (95% confidence interval) was 32.1% (31.2-33.0) by the IDF definition, 33.2% (32.3-34.1) by the ATPIII and 18.4% (17.6-19.2) according to the WHO definition. The sensitivity, specificity and concordance of the IDF definition for detecting MES were 91%, 89% for the ATPIII definitions and 73%, 77% for the WHO definition, respectively. The k statistics for the agreement of the IDF definition was 66.3±0.01 with the ATPIII and 39.5±0 with the WHO definition.

Conclusion: In the Iranian population, the IDF definition for MES has a good concordance with the ATP III definition and a low concordance with the WHO definition.

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Background: The aim of this study was to examine the prevalence of the metabolic syndrome (MetS) and its association with coronary heart disease (CHD) in Iranian older individuals.

Methods: In this cross-sectional study, the prevalence of the MetS was determined according to the Third Adult Treatment Panel (ATPIII), the World Health Organization (WHO) and the International Diabetes Federation (IDF) definitions in 720 men and women aged≥65 years. Logistic regression analysis was used to estimate the Odds Ratio (OR) of developing CHD in model 1 an age adjusted model, in model 2 adjusted for age, smoking status, premature history of CHD and LDL cholesterol and in model 3 adjusted for mentioned variables in model 2 plus the components of the MetS according to each definition.

Results: The prevalence of MetS was 50.8%, 41.9% and 41.8% by ATPIII, IDF and the WHO definitions, respectively. IDF had high agreement with the ATPIII definition. In model 2, the ATPIII and the WHO definitions of MetS were associated with CHD by the odds ratio of 1.6 (1.1-2.2) and 1.7 (1.9-2.4), respectively. In model 3, obesity (WHO definition) and high blood pressure (ATPIII and WHO definitions) were associated with CHD.

Conclusion: As defined by the ATPIII and WHO definitions, the MetS was associated with CHD even after adjustment for the conventional CHD risks, but after further adjustment for their components none of these definitions showed association with CHD.

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Background: Non- alcoholic fatty liver disease (NAFLD) is a pathogenic factor of insulin resistance and type 2 diabetes. On the other hand, the circulating liver enzymes including Aspartate aminotransferase (AST), Alanin aminotranferase (ALT) and Gamma glutamyl transferase (GGT) are commonly elevated in asymptomatic patients with NAFLD.

Methods: As a nested case-control study, AST, ALT, GGT as well as classic diabetes risk factors, homeostatic model assessment of insulin resistance(HOMA- IR) and C-reactive protein (CRP) were measured in 133 non-diabetic subjects at baseline (68 cases and 65  controls). Conditional logistic regression was used to calculate the odds ratio (OR) of diabetes associated with different hepatic markers. We used factor analysis for clustering of classic diabetes risk factors.

Results: In Univariate analysis, both ALT and GGT were associated with diabetes with ORs of 3.07(1.21-7.79) and 2.91(1.29-6.53), respectively. After adjustment for CRP and insulin, ALT and GGT were still predictive of incident diabetes. When the model was further adjusted for anthropometric, blood pressure and metabolic factors resulted from factor analysis (full model), only ALT was independently associated with diabetes [OR=3.06 (1.01-9.26)]. No difference was found between the area under the receiver operating characteristic curves of the models with and without ALT (0.820 and 0.802 respectively, P=0.4)

Conclusion: ALT is associated with incident type 2 diabetes independent of classic risk factors. However, its addition to the classic risk factors does not improve the prediction of diabetes.