Cohort profile update: Tehran cardiometabolic genetic study.

The Tehran cardiometabolic genetic study (TCGS) is a large population-based cohort study that conducts periodic follow-ups. TCGS has created a comprehensive database comprising 20,367 participants born between 1911 and 2015 selected from four main ongoing studies in a family-based longitudinal framework. The study's primary goal is to identify the potential targets for prevention and intervention for non-communicable diseases that may develop in mid-life and late life. TCGS cohort focuses on cardiovascular, endocrine, metabolic abnormalities, cancers, and some inherited diseases. Since 2017, the TCGS cohort has augmented by encoding all health-related complications, including hospitalization outcomes and self-reports according to ICD11 coding, and verifying consanguineous marriage using genetic markers. This research provides an update on the rationale and design of the study, summarizes its findings, and outlines the objectives for precision medicine.

A pragmatic multi-setting lifestyle intervention to improve leisure-time physical activity from adolescence to young adulthood: the vital role of sex and intervention onset time.

BACKGROUND: The long-term effectiveness of healthy lifestyle interventions on improving leisure-time physical activity (LTPA) in adolescents and its factors in low- and middle-income communities is unclear. This study is the first to investigate LTPA trends in a population of Iranian adolescents who underwent a multi-setting lifestyle intervention, considering sex and the time of intervention onset. METHODS: Participants were 2374 adolescents (57.2% girls), aged 12-18 years, who participated in the Tehran Lipid and Glucose Study (TLGS) during 1999-2001 and followed for a median follow-up of 15.9 over five data points every 3 years. Adolescent participants were assigned to the intervention or control groups based on their residential areas. Boys and girls were categorized into 12-15 or 16-18 years old to minimize participants' bio-psychological differences, facilitate environmental interventions by more compliance with the Iranian educational system and identify the best time to start the intervention. All adolescents in the intervention area received healthy lifestyle interventions via the school-, family-, and community-based programs. LTPA was assessed using the reliable and validated Iranian Modifiable Activity Questionnaire (MAQ) version over the five data points. The Generalized Estimating Equations method was used to evaluate educational intervention's effect on LTPA in adolescents during the follow-up. RESULTS: In boys who experienced the early onset of intervention (12-15 years), the interaction effect of follow-up examinations and the intervention was significant where the impact of the intervention differed over time. In this group, LTPA was higher in the control group than in the intervention group at the first follow-up examination (ß = - 1088.54). However, an increasing trend of LTPA was observed in the intervention group until the third follow-up examination (ß = 1278.21, p = 0.08, and ß = 1962.81, p = 0.02, respectively), with borderline significance levels at the 2nd (P = 0.08) and the 4th (P = 0.08) measurements. The interaction terms and main effects of intervention and follow-up examinations were not significant in boys with late intervention onset. Although older boys in the intervention group had higher LTPA than the control group, there were no significant differences among study groups in all follow-up examinations. Regarding girls, LTPA did not differ significantly between intervention and control groups in all follow-up examinations (P > 0.05). CONCLUSION: Our results showed that a multi-setting practical lifestyle intervention could improve long-term energy expenditure in LTPA in adolescent boys who have experienced an early onset intervention. Findings emphasized the vital role of gender and the onset of these interventions. The current results would be valuable to plan tailored interventions to improve LTPA and community health. TRIAL REGISTRATION: This study is registered at Iran Registry for Clinical Trials (IRCT), a WHO primary registry ( http://irct.ir ). The TLGS clinical trial was the very first registration in the IRCT (Iran Registry of Clinical Trials). it was registered on 2008-10-29 by the registration number IRCT138705301058N1 . Based on the international committee of medical journal Editors (ICMJE), "retrospective registration" is acceptable for trials that began before July 1, 2005.

Sex-specific prevalence of coronary heart disease among Tehranian adult population across different glycemic status: Tehran lipid and glucose study, 2008-2011.

BACKGROUND: Coronary heart disease (CHD) is one of the leading causes of death. Alarmingly Iranian populations had a high rank of CHD worldwide. The current study aimed to assess the prevalence of CHD across different glycemic categories. METHODS: This study was conducted on 7718 Tehranian participants (Men = 3427) aged ≥30 years from 2008 to 2011. They were categorized based on glycemic status. The prevalence of CHD was calculated in each group separately. CHD was defined as hospital records adjudicated by an outcome committee. The association of different glycemic categories with CHD was calculated using multivariate logistic regression, compared with normal fasting glucose /normal glucose tolerance (NFG/NGT) group as reference. RESULTS: The age-standardized prevalence of isolated impaired fasting glucose (iIFG), isolated impaired glucose tolerance (iIGT), both impaired fasting glucose and impaired glucose tolerance (IFG/IGT), newly diagnosed diabetes mellitus (NDM), and known diabetes mellitus (KDM) were 14.30% [95% confidence interval (CI): 13.50-15.09], 4.81% [4.32-5.29], 5.19% [4.71-5.67], 5.79% [5.29-6.28] and 7.72% [7.17-8.27], respectively. Among a total of 750 individuals diagnosed as cases of CHD (398 in men), 117 (15.6%), 453 (60.4%), and 317 (42.3%) individuals had a history of myocardial infarction (MI), cardiac procedure, and unstable angina, respectively. The age-standardized prevalence of CHD for the Tehranian population was 7.71% [7.18-8.24] in the total population, 8.62 [7.81-9.44] in men and 7.19 [6.46-7.93] in women. Moreover, among diabetic participants, the age-standardized prevalence of CHD was 13.10 [9.83-16.38] in men and 10.67 [8.90-12.44] in women, significantly higher than corresponding values for NFG/NGT and prediabetic groups. Across six levels of glycemic status, CHD was associated with IFG/IGT [odds ratio (OR) and 95% CI: 1.38 (1.01-1.89)], NDM [1.83 (1.40-2.41)], and KDM [2.83 (2.26-3.55)] groups, in the age- and sex-adjusted model. Furthermore, in the full-adjusted model, only NDM and KDM status remained to be associated with the presence of CHD by ORs of 1.40 (1.06-1.86) for NDM and 1.91 (1.51-2.43) for KDM. CONCLUSION: The high prevalence of CHD, especially among diabetic populations, necessitates the urgent implementation of behavioral interventions in the Tehranian population, according to evidence-based guidelines for the clinical management of diabetic patients.

Diabetic population mortality and cardiovascular risk attributable to hypertension: a decade follow-up from the Tehran Lipid and Glucose Study.

To determine the extent to which burden of cardiovascular disease (CVD) outcomes among diabetic population is attributable to hypertension. Nine-year follow-up data were secured for 7068 participants aged ≥ 20 years old, free from CVD at baseline. Cox proportional hazards regression was implemented to estimate hazard ratios (HRs) of hypertension. Population-attributable hazard fraction (PAHF) was used to assess proportion of diabetic population hazard of CVD events and mortality attributable to hypertension. In the whole population, irrespective of diabetes or hypertension status, incidence rate (95% CI) of CVD, coronary heart disease (CHD), as well as CVD and all-cause mortality per 1000 person-year were 8.3 (7.6-9.0), 7.1 (6.5-7.8), 1.8 (1.5-2.1) and 3.9 (3.5-4.5), respectively. Among diabetes participants, hypertension was a risk factor for CHD (HR = 1.63, 95% CI 1.15-2.03), CVD (HR = 1.74, 95% CI 1.50-2.41), CVD mortality (HR = 1.65, 95% CI 0.87-3.12) and all-cause mortality (HR = 1.53, 95% CI 0.97-2.42). HRs, however, were not statistically significant for all-cause or CVD mortality. PAHFs (%) of hypertension was 27.5 (95% CI 8.3-42.6) for CHD, 29.6 (95% CI 10.6-44.4) for CVD, 27.9 (95% CI - 17.2 to 55.7) for CVD mortality and 22.6 (95% CI - 5.9 to 43.4) for all-cause mortality. Our study shows that there is an excess risk of CVD in hypertensive patients with diabetes related to inadequate control of blood pressure.

Leisure-time physical activity and its association with metabolic risk factors in Iranian adults: Tehran Lipid and Glucose Study, 2005-2008.

We examined the association between leisure-time physical activity (LTPA) and metabolic syndrome (MetS) among 4,665 randomly selected adults who participated in the Tehran Lipid and Glucose Study, 2005-2008. Normal-weight participants with light LTPA had higher risk of low high-density lipoprotein cholesterol and elevated levels of triglycerides than those with vigorous LTPA. Overweight adults with moderate LTPA had higher risk of having elevated levels of fasting blood glucose than adults with vigorous LTPA and, in the same group, we found an inverse association between light LTPA and MetS after adjustment for sex, age, education levels, smoking, and calorie intake. Although participants in the normal-weight and obese groups with vigorous LTPA had higher risk of high systolic blood pressure than participants with moderate LTPA, this finding had no clinical significance. Increased LTPA is associated with decreased risk of any damaging changes in the markers of MetS.

Shadow of diabetes over cardiovascular disease: comparative quantification of population-attributable all-cause and cardiovascular mortality.

BACKGROUND: We contrasted impacts on all-cause and cardiovascular disease (CVD) mortality of diabetes vs. CVD. METHODS: Among participants the Tehran lipid and glucose study aged ≥ 30 years (n = 9752), we selected those who participated in the follow-up study until 20 March 2009 (n = 8795). Complete data on covariate were available for 8, 469 participants, contributing to a 67935 person-year follow up. In the analysis of outcomes (all-cause and CVD mortality), diabetes and CVD were assessed using Cox proportional hazard regression model adjusting for established CVD risk factors. We used population attributable hazard fraction (PAHF) and rate advancement period (RAP) that expresses how much sooner a given mortality rate is reached among exposed than among unexposed individuals. RESULTS: Ten percent of the participants self-reported to have pervious CVD, and diabetes was ascertained in 17% of participants at baseline examination. During a median follow-up of 9 years 386 participants died of which 184 were due to CVD. All-cause and CVD mortality rate (95% CIs) were 5.5 (5.0-6.1) and 2.6 (2.3-3.0) per 1000 person-year, respectively. The PAHF of all-cause mortality for diabetes 9.2 (7.3-11.1) was greater than the one for CVD 3.5 (1.1-5.5). RAP estimates for all-cause mortality associated with diabetes ranged from 7.4 to 8.6 years whereas the RAP estimates for all-cause mortality associated with CVD ranged from 3.1 to 4.3 years. The PAHF of CVD mortality for diabetes 9.4 (6.8-12.0) was greater than the one for CVD 4.5 (1.8-7.0). RAP estimates for CVD mortality associated with diabetes ranged from 8.2 to 9.8 years whereas the RAP estimates for CVD mortality associated with CVD ranged from 4.7 to 6.7 years. CONCLUSIONS: We demonstrated that diabetes, which was shown to be keeping pace with prevalent CVD in terms of conferring excess risk of incident CVD, is currently causing more deaths in the population than does CVD.

Trends in risk factors for cardiovascular disease among Iranian adolescents: the Tehran Lipid and Glucose Study, 1999-2008.

OBJECTIVES: Data on secular trends in adolescent obesity and dyslipidemia are limited. Data on obesity status collected during 3 surveys were used to evaluate these trends in obesity and dyslipidemia among Tehranian adolescents and to assess the likelihood of risk factors for cardiovascular disease. METHODS: We analyzed data for adolescents (age 10 to 19 years) from 3 cross-sectional surveys of the Tehran Lipid and Glucose Study: 1999-2001 (n = 3010, 47.2% males), 2002-2005 (n = 1107, 48.4% males), and 2006-2008 (n = 1090, 46.6% males). Overweight and abdominal obesity were defined using Iranian body mass index (BMI) percentiles, International Obesity Task Force (IOTF) criteria, and Iranian waist circumference (WC) charts. Hypertension was defined by using the National Heart, Lung, and Blood Institute's recommended cut points, and dyslipidemia was defined according to the recent recommendations of the American Heart Association. RESULTS: The overall adjusted prevalences of "at risk for overweight" and overweight changed from 13% and 8% (using Iranian cutoffs), respectively, and 14.8% and 4.7% (using IOTF criteria) in 1999-2001 to 19% and 15% (Iranian cutoffs) and 23.0% and 9.2% (IOTF criteria) in 2006-2008 (P < 0.01 for all comparisons). The prevalence of abdominal obesity increased in males from 14.5% in 1999-2001 to 33.3% in 2006-2008 (P < 0.001). Almost half the adolescents had low high-density lipoprotein cholesterol (HDL-C) in the 3 surveys. In all surveys, as BMI and WC increased, multivariate age- and sex-adjusted odds ratios of low HDL-C and high triglyceride levels significantly increased. Overweight was associated with a greater likelihood of these risk factors, as compared with increased WC. CONCLUSIONS: Overweight and abdominal obesity are increasing in Tehranian adolescents, and these increases are accompanied by abnormalities in levels of serum triglyceride and HDL-C.

Time-varying association between physical activity and risk of diabetes in the early and late adulthood: A longitudinal study in a West-Asian country.

BACKGROUND: The time-varying association between physical activity (PA) and incidence of type 2 diabetes (T2DM) is still unclear. The present study aimed to investigate this association in the early- and late-adulthood during a 9-year follow-up. METHODS: This study was conducted on 3905 participants in early and late adulthood, using the Tehran Lipid and Glucose Study (TLGS) dataset. PA was assessed via the Iranian version of Modified Activity Questionnaire (MAQ). The association between trend of PA and incident T2DM was investigated using time-varying Cox's proportional hazard model. Variables including job, education, smoking and body mass index (BMI) were adjusted in the final model. RESULTS: The distribution of sex- and age-specific levels of PA changed significantly over time. Compared with physically inactive women, for older women with high level of PA, the risk of T2DM was 0.64 (95% CI: 0.43-0.95, P = 0.02) in adjusted model. Moreover, hazard for low PA group was significantly higher than the moderate group, and for these two groups were significantly higher than high PA level (P < 0.05). CONCLUSION: High PA level can postpone the incident T2DM in early-aged and elderly women, over time. Therefore, gender and age are of great importance in designing the PA modifying programs to prevent T2DM.

The association between transition from metabolically healthy obesity to metabolic syndrome, and incidence of cardiovascular disease: Tehran lipid and glucose study.

Considering that the data available on the cardiovascular (CV) risk of metabolically healthy obesity phenotype, and the effect of transition to an unhealthy status are inconsistent, the aim of this study was to investigate the possible role of transition to unhealthy status among metabolically healthy overweight/obese (MHO) subjects on CVD incidence over a median follow-up of 15.9 years. In this large population-based cohort, 6758 participants (41.6% men) aged ≥ 20 years, were enrolled. Participants were divided into 4 groups based on their obesity phenotypes and follow-up results, including persistent metabolically healthy normal weight (MHNW), persistent MHO, transitional MHO and metabolically unhealthy overweight/obese (MUO). Metabolic health was defined as not having metabolic syndrome based on the Joint Interim Statement (JIS) criteria. Multivariable adjusted hazard ratios (HRs) were calculated for cardiovascular events. During follow-up, rate of CVD Incidence per 1000 person-years were 12 and 7 in males and females, respectively. Multivariable adjusted HRs (CI 95%) of CVD incidence among males and females were 1.37 (.78-2.41) and .85 (.34-2.15) in persistent MHO group, 1.55 (1.02-2.37) and .93 (.41-2.12) in transitional MHO group and 2.64 (1.89-3.70) and 2.65 (1.24-5.68) in MUO group. Our findings showed that CVD risk did not increase in the persistent MHO phenotype over a 15.9-year follow-up in both sexes. However, transition from MHO to MUO status during follow-up increased the CVD risk just in male individuals. Further studies are needed to provide conclusive evidence in favor of benign nature of transitional MHO phenotype in females.

Long-term effectiveness of a lifestyle intervention on the prevention of type 2 diabetes in a middle-income country.

This study aims to assess the effects of a community-based lifestyle intervention program on the incidence of type 2 diabetes (T2D). For this purpose, three communities in Tehran were chosen; one community received a face-to-face educational session embedded in a long-term community-wide lifestyle intervention aimed at supporting lifestyle changes. We followed up 9,204 participants (control: 5,739, intervention: 3,465) triennially from 1999 to 2015 (Waves 1-5). After a median follow-up of 3.5 years (wave 2), the risk of T2D was 30% lower in the intervention community as compared with two control communities by (Hazard-ratio: 0.70 [95% CI 0.53; 0.91]); however, the difference was not statistically significant in the following waves. After a median follow-up of 11.9 years (wave 5), there was a non-significant 6% reduction in the incidence of T2D in the intervention group as compared to the control group (Hazard-ratio: 0.94 [0.81, 1.08]). Moreover, after 11.9 years of follow-up, the intervention significantly improved the diet quality measured by the Dietary Approaches to Stop Hypertension concordance (DASH) score. Mean difference in DASH score in the intervention group versus control group was 0.2 [95% CI 0.1; 0.3]. In conclusion, the intervention prevented T2D by 30% in the short-term (3.5 years) but not long-term; however, effects on improvement of the diet maintained in the long-term.Registration: This study is registered at IRCT, a WHO primary registry ( https://irct.ir ). The registration date 39 is 2008-10-29 and the IRCT registration number is IRCT138705301058N1.

Familial aggregation of the metabolic syndrome: Tehran Lipid and Glucose Study.

AIMS: Familial aggregation of the metabolic syndrome has been reported in some nations. The aim of this study was to evaluate familial aggregation of the metabolic syndrome in Tehranian families. METHODS: In a cross-sectional study, anthropometry, blood pressure and biochemical data were collected for 4,558 individuals in the Tehran Lipid and Glucose Study. Variables of the metabolic syndrome in offspring were correlated with those of their parents. RESULTS: There were 1,274 fathers, 1,576 mothers, 802 sons and 906 daughters. Prevalence of metabolic syndrome was 24.4% for fathers, 39.7% for mothers, 9.0% for sons and 7.6% for daughters. Triglycerides and HDL-C of children whose fathers had metabolic syndrome, and BMI, triglycerides and HDL-C of those whose mothers had it were significantly different from those adolescents whose parents were free of metabolic syndrome. Compared with children whose parents did not have metabolic syndrome, the odds ratio (confidence interval) for children with both parents having metabolic syndrome was 4.53 (2.42-8.8) for metabolic syndrome, 2.22 (1.17-4.19) for abdominal obesity, 1.90 (1.15-3.13) for high blood pressure, 2.66 (1.77-4.00) for low HDL-C and 3.16 (2.10-4.75) for high triglyceride levels. CONCLUSION: This survey provides evidence suggesting that there is a familial aggregation of the metabolic syndrome among Iranian families.

Seasonal Variations of Serum Zinc Concentration in Adult Population: Tehran Lipid and Glucose Study.

BACKGROUND: Zinc, an essential trace element, plays a key role in many biological human body functions. Serum zinc concentration is the most widely used indicator of zinc status for general populations. Considering the limited data available on seasonal fluctuation of serum zinc concentration, we aimed at determining seasonal variations in serum zinc concentrations of Tehranian adults. METHODS: The current study was conducted within the framework of the Tehran Lipid and Glucose Study, on 4698 subjects, aged ≥20 years. Serum zinc samples of subjects were obtained from all four seasons over three years (from 2009 to 2011); samples of similar seasons over three years were placed in one group and the geometric means of serum zinc concentration of four seasons were compared to determine possible seasonal variations. RESULTS: Participants with mean age 46.3 yr and geometric mean of serum zinc concentration 116.3 µg/dl, were studied for almost three years through four seasons. Serum zinc concentrations in spring and summer were significantly higher than those in autumn and winter (112.2 and 114.4 vs. 106.7 and 104.8 µg/dl; P<0.001, respectively). Moreover, monthly serum zinc concentration of all subjects differed, with the lowest and highest levels found in October and August (98.5 vs. 122.7; P<0.001). CONCLUSION: This study demonstrates the difference in serum zinc concentration in Iranian adults of both genders in different months and seasons during the year.

Application of Latent Class Analysis to Identify Metabolic Syndrome Components Patterns in adults: Tehran Lipid and Glucose study.

In this study, using latent class analysis (LCA), we investigated whether there are any homogeneous subclasses of individuals exhibiting different profiles of metabolic syndrome (MetS) components. The current study was conducted within the framework of the Tehran Lipid and Glucose Study (TLGS), a population-based cohort including 6448 subjects, aged 20-50 years. We carried out a LCA on MetS components and assessed the association of some demographic and behavioral variables with membership of latent subclasses using multinomial logistic regression. Four latent classes were identified:(1) Low riskclass, with the lowest probabilities for all MetS components (its prevalence rate in men: 29%, women: 64.7%), (2) MetS with diabetes medication (men: 1%, women: 2.3%), (3) Mets without diabetes medication (men: 32%, women: 13.4%), (4) dyslipidemia (men: 38%, women: 19.6%). In men the forth subclass was more significantly associated with being smoker (odds ratio: 4.49; 95% CI: 1.89-9.97). Our study showed that subjects with MetS could be classified in sub-classes with different origins for their metabolic disorders including drug treated diabetes, those with central obesity and dyslipidemia associated with smoking.

The interaction of cholesteryl ester transfer protein gene variations and diet on changes in serum lipid profiles.

BACKGROUND/OBJECTIVES: Gene-diet interactions may have an important role in the disparities between the lipid responses of individuals to diet. This study aimed to investigate whether polymorphisms (rs5882 and rs3764261) in the cholesteryl ester transfer protein (CETP) gene modify the association of diet with changes in serum lipid profiles. SUBJECTS/METHODS: A total of 4700 individuals aged ≥18 years were selected from among participants of the Tehran Lipid and Glucose Study. After 3.6 years of follow-up, changes in serum lipid profiles were evaluated. Usual dietary intake was assessed using a validated food frequency questionnaire. DNA samples were genotyped with HumanOmniExpress-24-v1-0 bead chips (containing 649,932 SNP loci). RESULTS: No significant interaction was found between CETP polymorphisms and dietary patterns in changing lipid profiles. Mean changes of total cholesterol (TC) decreased in higher quartiles of fish intake in A allele carriers (Q1:8.02, Q4:5.58, Ptrend = 0.01) compared to the CC genotype (Q1:3.65, Q4:8.93, Ptrend = 0.11) (Pi = 0.02). There are ascending trends of changes in triglyceride (TG) concentrations across quartiles of total fat, monounsaturated and saturated fat consumption in G allele carriers of rs5882 compared to the AA genotype. There was a declining trend for mean changes in TG concentrations across quartiles of carbohydrate intake in G allele carriers of rs5882 compared to the AA genotype (Pi = 0.01). CONCLUSIONS: Our data demonstrated that minor allele carriers of rs5882 had a better TG value than AA homozygote individuals when consuming a low fat and high carbohydrate diet. Fish intake modifies the association of rs3764261with TC concentrations.

The Impact of Physical Activity on Non-communicable Diseases: Findings from 20 Years of the Tehran Lipid and Glucose Study.

CONTEXT: Low physical activity is one of the major risk factors for non-communicable diseases (NCD) such as cardiovascular disease and type 2 diabetes. The current paper reviews the main findings from Tehran lipid and glucose study (TLGS) that focus on physical activity and its association with cardiometabolic risk factors over the past two decades. EVIDENCE ACQUISITION: We conducted a literature search for articles from 1999 to December 2017 using the search terms: (Physical activity, leisure time physical activity, non-communicable disease, and TLGS). RESULTS: The prevalence of low physical activity was 69.8% during phase ΙΙ of TLGS (2000 - 2004). During 6.5 years of follow up, the prevalence of low physical activity in the total population decreased significantly between phases II (2000 - 2004) and IV of TLGS (2008 - 2010) (P < 0.05). Overweight individuals with sedentary lifestyles had a higher risk of metabolic syndrome, compared to those who had high levels of leisure-time physical activity in phase IV of TLGS (2008 - 2010); in the obese group, systolic blood pressure, and triglyceride levels differed significantly between different leisure-time physical activity categories (106.9 ± 14.3 vs. 119.1 ± 17.2 mmHg, P = 0.03) and (111.4 ± 1.6 vs. 147.1 ± 1.6 mg/dL, P = 0.01), respectively. CONCLUSIONS: The present review highlights the impact of low physical activity on the health of the TLGS community from adolescence to adulthood. The decreased prevalence of low physical activity from phase ΙΙ to phase ΙV of TLGS indicates the necessity for lifestyle interventions as a potentially effective strategy, which could have a positive impact on various risk factors and indicators of non-communicable diseases such as body mass index, waist circumference, systolic blood pressure, and lipid profiles.

Outcomes of a Longitudinal Population-based Cohort Study and Pragmatic Community Trial: Findings from 20 Years of the Tehran Lipid and Glucose Study.

CONTEXT: The Tehran lipid and glucose study (TLGS) is one of the oldest population-based longitudinal cohort studies, providing knowledge about the incidence and risk factors of some non-communicable diseases (NCDs) in West Asia which hitherto was relatively scarce. We reviewed the methods and results related to the outcome measurements of this study. EVIDENCE ACQUISITION: We reviewed all the TLGS papers which reported the incidence of NCDs. RESULTS: The TLGS was initiated in 1999 - 2001 on a population in district no. 13 of Tehran with the same age distribution of the overall Tehran population and with a middle socioeconomic status. Totally, 15005 individuals, aged ≥ 3 years, participated in the first examination; reexaminations were conducted in a triennial manner and 3550 individuals were added in the second examination. All participants were also followed up annually and asked about any medical event leading to hospitalization or death. A part of participants was assigned to an educational program for lifestyle modification. High incidence of cardiovascular disease (CVD), premature CVD, diabetes and hypertension (around 19, 6, 10 and 31 in men and 11, 5, 11 and 29 in women per 1000 person-year, respectively) besides the high incidence of pre-diabetes and pre-hypertension (around 46 and 76 in men and 37 and 49 in women per 1000 person-year, respectively) showed a worrying situation. Fortunately, the results of the community interventions were promising with around 20% reduction in the risk of metabolic syndrome up to six years. CONCLUSIONS: These precise detections of different outcomes in the TLGS provided valuable evidences for prediction and prevention of NCDs in Iran with some novelties in the middle-income countries in the world. The Tehran thyroid study (TTS) and the Tehran cardiometabolic genetic study (TCGS), conducted in the framework of the TLGS, are among few studies aiming to determine the natural course of thyroid function and to identify patterns of genetic polymorphisms related to cardiometabolic outcomes, respectively.

The Effects of a Community-Based Lifestyle Intervention on Metabolic Syndrome and Its Components in Adolescents: Findings of a Decade Follow-Up.

BACKGROUND: The increasing prevalence of metabolic syndrome (MetS) in childhood makes lifestyle interventions imperative during adolescence. This study aimed to assess the effects of a community-based lifestyle intervention on MetS and its components in adolescents. METHODS: Adolescents, based on their residential area were categorized into three groups: complete intervention (residing in the intervention area at baseline and during all follow-ups), incomplete intervention (residing in either the intervention or control areas and were in transition between these two areas), and control group (residing in the control area at baseline and throughout all follow-ups). All measurements were repeated every 3 years for up to 9 years. Lifestyle intervention aimed at achieving healthy dietary patterns and increasing physical activity. Generalized estimating equation models were used to analyze data. RESULTS: In boys with incomplete intervention versus controls, the prevalence of MetS was significantly lower in the short term (14.0 vs. 22.9), but not in long term. In boys with complete intervention, the prevalence was significantly lower versus controls (9.0 vs. 23.4) in the long term. In girls, the short-term prevalence of MetS was significantly lower in the complete intervention group compared with controls (2.5 vs. 9.1) and then remained constantly low in all study groups after that. Among MetS components, in boys, triglycerides and fasting plasma glucose in the short term and high-density lipoprotein mid term, and in girls HDL in mid and long term were both significantly improved. The odds of MetS decreased significantly in the complete [odds ratio (OR): 0.516, confidence interval (95% CI): 0.273-0.973] and incomplete (OR: 0.591, 95% CI: 0.358-0.976) intervention groups only in boys. The short- and long-term interventions resulted improvement in some of the MetS components in both genders. CONCLUSIONS: The healthy lifestyle intervention reduced the risk of MetS in both genders in short and long term, but with different patterns and improved some of the MetS components.

The hypertriglyceridemic waist and waist-to-height ratio phenotypes and chronic kidney disease: Cross-sectional and prospective investigations.

AIMS: We investigated the association between two hypertriglyceridemic waist (HW) and waist-to height ratio (HWHtR) phenotypes and chronic kidney disease (CKD) using cross sectional and prospective analysis. METHODS: Data of 12,012 individuals (44% men) of the Tehran Lipid and Glucose Study (TLGS) at two phases [(1999-2001) and (2002-2005)], were used for cross-sectional analysis. This population was followed until 2014 with median follow-up 12.4 years (95% confidence interval (CI): 11.8; 12.4). The data of 8225 individuals (45% men) were used for prospective analysis. The outcome was the development of CKD defined as estimated glomerular filtration rate (eGFR) <60mL/min/1.73m2. The HW phenotype was defined as waist circumference (WC) >90cm in men and >85cm in women, along with TGs >2.0mmol/L. The HWHtR phenotype was defined as waist-to-height ratio (WHtR) >0.5 and TGs >2mmol/L. Multivariable logistic and Cox regression were used to statistical analysis. RESULTS: Cross sectional analysis showed that in women, both HW and HWHtR phenotypes were associated with CKD after controlling for confounders [(OR: 1.37, CI: 1.01-1.86, p<0.05) and (OR: 1.58, CI: 1.03-2.41, p<0.05)], respectively. Among men, HW and HWHtR were associated with prevalent CKD in unadjusted and age adjusted models; these associations were not significant after further adjustment for confounders. In prospective analysis, neither HW nor HWHtR phenotypes were significant predictor for CKD progression. CONCLUSION: HW and HWHtR phenotypes were associated with prevalent CKD in cross sectional setting. In prospective analysis HW and HWHtR did not show significant effect in prediction of CKD.

Rationale and Design of a Genetic Study on Cardiometabolic Risk Factors: Protocol for the Tehran Cardiometabolic Genetic Study (TCGS).

BACKGROUND: Cardiometabolic risk factors comprise cardiovascular diseases and/or diabetes, and need to be evaluated in different fields. OBJECTIVE: The primary aim of the Tehran Cardiometabolic Genetic Study (TCGS) is to create a comprehensive genome-wide database of at least 16,000 Tehranians, who are participants of the ongoing Tehran Lipid and Glucose Study (TLGS) cohort. METHODS: TCGS was designed in collaboration with the Research Institute for Endocrine Sciences and the genetic company deCODE. Participants had already been followed for over a 20-year period for major cardiometabolic-related health events including myocardial infarction, stroke, diabetes mellitus, hypertension, obesity, hyperlipidemia, and familial hypercholesterolemia. RESULTS: The TCGS cohort described here comprises 17,186 (86.3%) of the 19,905 TLGS participants who provided a baseline blood sample that was adequate for plasma and deoxyribonucleic acid analysis. This study is comprised of 849 individuals and 3109 families with at least one member having genotype information. Finally, 5977 males and 7422 females with the total genotyping rate of 0.9854 were genotyped with HumanOmniExpress-24-v1-0 bead chips (containing 649,932 single-nucleotide polymorphism loci with an average mean distance of 4 kilobases). CONCLUSIONS: Investigations conducted within the TCGS will seek to identify relevant patterns of genetic polymorphisms that could be related to cardiometabolic risk factors in participants from Tehran. By linking genome-wide data to the existing databank of TLGS participants, which includes comprehensive behavioral, biochemical, and clinical data on each participant since cohort inception in 1999, the TCGS will also allow exploration of gene-gene and gene-environment interactions as they relate to disease status.

Familial Aggregation of Metabolic Syndrome With Different Socio-Behavioral Characteristics: The Fourth Phase of Tehran Lipid and Glucose Study.

BACKGROUND: Since genetic and most environmental factors shape the context of families, some studies have been initiated to investigate the role of familial relationships in metabolic syndrome (MetS). OBJECTIVES: To estimate the familial aggregation of MetS and its components by identifying both case and control probands among Tehranian adults with different socio-behavioral and reproductive characteristics. PATIENTS AND METHODS: This case-controlled/family-based study was conducted on 1,777 families (635 case probands) who participated in the Tehran Lipid and Glucose Study (TLGS). Socio-demographic and reproductive information including levels of education, marital status, occupation status, age at menarche, number of abortions, number of children, and lifestyle habits such as smoking, physical activity and regular diet were obtained from the TLGS data bank. Metabolic syndrome was defined according to the joint interim statement (JIS) criteria. To estimate the regression co-efficient for familial aggregation and environmental factors, the generalized estimation equation method was used. RESULTS: The risk of having MetS among family members for case versus control probands was 2.19 (95% CI: 1.68 - 2.84), which, after adjusting for potential confounders including age, sex, educational level, marital status, occupation, age at menarche and energy, soft drink and starchy vegetable intake, increased to 2.31 (95% CI: 1.81 - 2.94; P < 0.05). Compared to control probands, the risk of having MetS components increased significantly from OR = 1.28 for both high waist circumference (WC) and blood pressure (BP) to OR = 1.72 for high triglycerides in cases. Familial aggregation inherited from the father was significantly observed in all MetS components, from adjusted OR = 1.63 for hyperglycemia to adjusted OR = 2.69 for high WC, except for low HDL, after controlling for potential confounders. CONCLUSIONS: Considering spouses and siblings, there was a higher risk for MetS components among families whose fathers and offspring had MetS components, implying the pivotal role of genetic inheritance in the incidence of the syndrome and its components.