Comprehensive evaluation of body composition in a wide age range of Iranian adults using bioelectrical impedance analysis: Tehran Lipid and Glucose Study.

OBJECTIVE: To evaluate sex- and age-stratified body composition (BC) parameters in subjects with wide age range of 20-79 years. DESIGN: Cross-sectional. SETTING: Participants of Tehran Lipid and Glucose Study (TLGS). PARTICIPANTS: Two thousand nine hundred seventy participants met our inclusion criteria. They were divided into five age groups, and BC parameters were analysed based on sex and age using a bioelectrical impedance analyser (BIA). RESULT: The mean age of the participants was 42·1 ± 12·5 years, and 54 % of them were males. The mean BMI was 26·7 ± 3·7 kg/m2. Obesity indices were significantly higher in females (P < 0·001); however, skeletal muscle mass (SMM) and fat-free mass (FFM) were significantly higher in males (P < 0·001). Both SMM and FFM decreased significantly after the age of 50 years. Obesity indices significantly increased from the age group of 20-29 to 30-39 years in males and the age groups of 30-39 to 40-49 years and 40-49 to 50-59 years in females. The fat mass ratio (fat mass/SMM) showed two peaks in both sexes (after the ages of 30 and 50 years in males and 40 and 50 years in females). A strong correlation was found between BMI and percentage of body fat (r = 0·823 in females v. r = 0·768 in males). CONCLUSION: This is the first community-based study in the MENA region identifying sex- and age-stratified BC values using BIA. Our findings can be used as a reference for comparison in appropriate settings.

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.

Body Composition Assessment by Bioelectrical Impedance Analysis in Prediction of Cardio-Metabolic Risk Factors: Tehran Lipid and Glucose Study (TLGS).

Background: We aimed at evaluating the best body mass index (BMI) and percent body fat (PBF) cutoffs related to cardio-metabolic risk factors and comparing the discriminative power of PBF and BMI for predicting these risk factors. Methods: In this cross-sectional study in phase V (2012-2015), 1271 participants (age ≥ 20 yr; 54.3% women) were enrolled. Bioelectrical impedance analysis (BIA) was used to estimate PBF. Joint Interim Statement criteria were used for defining metabolic syndrome (MetS). We compared PBF with BMI through logistic regression and area under the curve of the receiver operating characteristic (ROC) curve. Percent body fat cutoff points were > 25 in men and >35 in women. Results: Percent body fat and BMI cutoff points for predicting MetS were 25.6% and 27.2 kg/m2 in men and 36.2% and 27.5 kg/m2 in women, respectively. There were no significant differences between BMI and PBF area under the ROC curves for predicting MetS and its components, except for abdominal obesity in men and low high-density lipoprotein (HDL) in women in favor of BMI. Logistic regression analysis indicated that BMI in women was better for predicting MetS and its components, except for abdominal obesity. Moreover, BMI was equal or superior to PBF in men, except for low HDL and high triglyceride levels. Conclusion: Comparison of PBF with BMI showed that the use of PBF is not significantly better than BMI in predicting cardio-metabolic risks in the general population.

Long-Term Effectiveness of a Lifestyle Intervention: A Pragmatic Community Trial to Prevent Metabolic Syndrome.

INTRODUCTION: The purpose of this study is to evaluate the long-term effectiveness of a community-based lifestyle education on primary prevention of metabolic syndrome in a middle-income country. STUDY DESIGN: This study followed 3,180 individuals free of metabolic syndrome who were under the coverage of three health centers in Tehran from 1999 until 2015. They were undergoing triennial examinations resulting in four re-exams. People in one of three areas received interventions consisting of family-, school-, and community-based educational programs, including a face-to-face educational session at baseline. Data were analyzed considering the incidence of metabolic syndrome at each re-exam and also repeated-measure analysis including all re-exams together. Weighting was considered to correct selection bias because of loss to follow-up. Data were analyzed in 2017. RESULTS: After 3 years, 149 of 852 participants in the intervention and 471 of 2,328 people in control area developed metabolic syndrome at first re-exam resulting in a RR of 0.78 (95% CI=0.67, 0.92). The difference between groups remained unchanged up to the 6-year follow-up (RR=0.79, 95% CI=0.66, 0.93, at second re-exam), but disappeared during the third and fourth re-exams (RR=1.04, 95% CI=0.91, 1.18 and RR=1.03, 95% CI=0.91, 1.16, respectively). Marginal models for longitudinal data showed a significant interaction between intervention and time of re-exams. Further analyses showed that the effect of the intervention might have been rooted in improvement of lipid profile and glucose level. CONCLUSIONS: In a middle-income country, face-to-face educational sessions followed by a long-term maintenance community-level educational program could reduce the risk of metabolic syndrome for up to 6 years. A booster face-to-face session is recommended to retain this preventive effect. TRIAL REGISTRATION: This study is registered at Iran Registry for Clinical Trials (http://irct.ir) IRCT138705301058N1.

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.

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.

Is systolic blood pressure below 150 mm Hg an appropriate goal for primary prevention of cardiovascular events among elderly population?

Recently, Joint National Committee has changed the optimal therapeutic goal of systolic blood pressure (SBP) up to 150 mm Hg for elderly population. We aimed to investigate impact of different blood pressure (BP) categories on risk of developing cardiovascular disease (CVD) and mortality among elderly. The present study included 1845 participants, aged ≥60 years (mean age = 65 years), free of CVD at baseline, who had undergone health examinations between January 1999 and 2001, and were followed up until March 2010. Cox proportional hazard regression was performed to assess the hazard ratios (HRs) of BP categories for CVD and mortality events, considering those with optimal BP (SBP <120 mm Hg and diastolic BP [DBP] <80 mm Hg) as reference. During a median of 10 years follow-up, 380 cases of first CVD and 260 cases of mortality events occurred. In multivariable adjusted model, prehypertensive group (SBP between 120-129 mm Hg or DBP between 80-85 mm Hg) could not predict CVD (HR, 0.87 [0.61-1.24]) nor mortality events (HR, 0.86 [0.58-1.34]). Those with SBP between 140 mm Hg and 150 mm Hg (group 3) were at higher risk for developing CVD (HR, 1.79 [1.17-2.74]), but there were no significant risk for total mortality (HR, 1.13 [0.65-1.97]). Hypertensive group (SBP ≥150 mm Hg or DBP ≥90 mm Hg or taking antihypertensive drugs) was associated with increased risk of both CVD (HR, 1.73 [1.24-2.42]) and mortality events (HR, 1.49 [1.00-2.23]).However, Joint National Committee 8 suggested no more benefit with lowering SBP <150 mm Hg, but the results of this study imply that those with SBP between 150 mm Hg and 140 mm Hg are still at elevated risk for CVD/coronary heart disease events.

The impact of smoking status on 9.3 years incidence of cardiovascular and all-cause mortality among Iranian men.

AIM: To examine the association of different smoking groups with cardiovascular disease (CVD), coronary heart diseases (CHD) and CVD attributed death and death due to all causes in a male Tehranian population. METHODS: From a population-based study 3059 male individuals, aged ≥30 years, free of CVD at baseline were evaluated for a median of 9.3 years. The adjusted hazard ratios (HRs) for incident CVD/CHD, total and CVD mortality regarding their smoking status were calculated using Cox proportional regression analysis, considering never smoking as reference. RESULTS: A total of 158 deaths, in which 78 were CVD attributable, occurred. Considering CVD and CHD events, this study identified 299 and 257 events, respectively. Being a past smoker significantly increased the risk of CVD events (HR = 2.42, CI = 1.28-0.56), however, it has no effect on CHD events, total and CVD mortality. Being a current smoker (more than 10 cigarettes a day) dramatically increased the risk of CVD/CHD events and total/CVD mortality. However, smoking less than 10 cigarettes per day only increased the risk of CVD (HR = 2.12, CI = 1.14-3.95) and its mortality (HR = 4.57, CI = 1.32-15.79). CONCLUSION: The findings indicate that smoking increases the risk of incident CVD/CHD, total and CVD mortality, particularly CVD mortality. These outcomes were attributable to the daily amount of cigarettes smoked. Past smokers still had higher risk for CVD events, which cessation may not reduce.

Hypertriglyceridemic waist: the point of divergence for prediction of CVD vs. mortality: Tehran Lipid and Glucose Study.

AIMS: We examined hypertriglyceridemic waist (HTGW) predictability for CVD and mortality. METHODS: Among Tehran Lipid and Glucose Study's participants aged ≥30 (n=8071), we selected those who participated in the follow-up study until 20-March-2009 (n=7154). After exclusions (320 missing data on waist circumference or triglycerides), 6834 (3830 women) participants remained eligible with a total of 59,873 person-year follow-up. When CVD was outcome, we further excluded 426 participants with history of previous CVD. RESULTS: All-cause mortality, CVD mortality, and incident CVD rate among men (per 1000-person-year) were 7.9 (95% CIs: 6.9-9.1), 4.1 (95% CIs: 3.4-5.0), and 13.0 (95% CIs: 11.7-14.6), respectively. Among women, corresponding figures were 3.7 (95% CIs: 3.1-4.4), 1.7 (95% CIs: 1.3-2.1), and 7.3 (95% CIs: 6.4-8.3), respectively. After adjustment for potential confounders, HTGW came to be inversely associated with all-cause mortality among both men (HR 0.384, 95% CIs 0.281-0.526) and women (HR 0.642, 95% CIs 0.430-0.958). Multivariate adjusted HR (95% CIs) of HTGW for CVD mortality was 0.453 (95% CIs 0.298-0.688) among men and 0.760 (95% CIs 0.431-1.338) among women. HTGW increased the age-adjusted risk of incident CVD, among both men (40%) and women (97%). The multivariate hazard ratio of HTGW for incident CVD was 0.945 (95% CIs 0.746-0.1.198, P value=0.640) among men and 1.470 among women (HR 95% CIs 1.111-1.944, P value=0.007). CONCLUSION: HTGW was the point of divergence for prediction of CVD vs. mortality. HTGW, despite its predictive value for CVD, might not help in capturing risk of all-cause or CVD mortality. Individuals without HTGW constitute a heterogeneous subgroup with a jumble of risk factors that put them at risk for all-cause or CVD mortality.

Performance of different definitions of metabolic syndrome for children and adolescents in a 6-year follow-up: Tehran Lipid and Glucose Study (TLGS).

AIM: To assess the utility of different definitions of the metabolic syndrome (MetS) in predicting adulthood MetS among Tehranian adolescents in a 6-year follow-up. METHODS: A random sample of 2645 adolescents was selected from the Tehran Lipid and Glucose Study (TLGS) in 1999-2001; MetS was assessed based on five definitions for adolescents. In 2005-2007, 572 age 18 years and over were assessed for MetS by NCEP ATP III adults' criteria. Sensitivity, specificity, and area under receiver operating curve for attaining adulthood MetS, obesity and overweight were calculated for each MetS definitions. RESULTS: The prevalence of adolescence MetS varied from 0.7+/-0.2 to 15.1+/-0.8% by different definitions in adolescents and 4.0+/-0.9% among adults. The highest area under curve for prediction of adulthood MetS pertained to the de Ferranti's definition (0.723), and for prediction of adulthood obesity and overweight were 0.723 and 0.606, respectively, for this definition. Kappa for agreement between these definitions was fair (0.195). CONCLUSIONS: Definition of MetS for adolescents showed a fair agreement with adult definition. Yet, a diagnosis of MetS in adolescents seems to be a good predictor of developing adulthood MetS within a short time.

Waist circumference has heterogeneous impact on development of diabetes in different populations: longitudinal comparative study between Australia and Iran.

AIMS: Comparing waist circumference (WC) role in diabetes risk prediction and diagnosis of metabolic syndrome (MS) in different populations. METHODS: Population-based samples from Australia (n=9026) and Iran (n=8259) were studied in 2000 and followed for approximately 4 years. Follow-up attendance was approximately 58% and mean age was 51 vs. 47. Pearson correlations calculated between WC and other MS components. ROC for the role of WC in the prediction of incident diabetes was used. RESULTS: Prevalences of MS (48% vs. 28%), an increased WC (58.5% vs. 54.5%), low HDL-C (35% vs. 11.2%), high triglyceride (52.2% vs. 29.6%) were significantly higher in Iran. Fasting glucose >or=5.6mmol/L was higher in Australia (26% vs. 23%). Hypertension was no different ( approximately 38%). Pearson correlations between WC and other MS components were stronger in Australians: FPG (0.32 vs. 0.2), HDL (0.47 vs. 0.16), TG (0.38 vs. 0.30) and SBP (0.38 vs. 0.36). Among women, area under ROC curve for WC as a predictor for diabetes was significantly higher for Australians (0.76 vs. 0.68, p<0.001) with no difference among men (0.69 vs. 0.71, p=0.4). CONCLUSION: WC was more strongly related to other components of MS in Australia. Association between WC and MS or incident diabetes varies between ethnicities.