Predictors of the incident metabolic syndrome in healthy obese subjects: a decade of follow-up from the Tehran Lipid and Glucose Study

Correlations between Coffee Consumption and Metabolic Phenotypes, Plasma Folate, and Vitamin B12: NHANES 2003 to 2006

Metabolic syndrome (MetS) is prevalent not only among the overweight and obese but also normal weight individuals, and the phenotype is referred to as a metabolically unhealthy phenotype (MUHP). Besides normal weight individuals, overweight/obese individuals are also protected from MetS, and the phenotype is known as a metabolically healthy phenotype (MHP). Epidemiological studies indicate that coffee and micronutrients such as plasma folate or vitamin B12 (vit. B12) are inversely associated with MetS. However, correlations among coffee consumption metabolic phenotypes, plasma folate, and vit. B12 remain unknown. Our objective was to investigate the correlation between coffee consumption, metabolic phenotypes, plasma folate, and vit. B12 as well as to understand associations between plasma folate, vit. B12, and metabolic phenotypes. Associations among coffee consumption metabolic phenotypes, plasma folate, and vit. B12 were assessed in a cross-sectional study of 2201 participants, 18 years or older, from 2003-2004 and 2005-2006 National Health and Nutrition Examination Surveys (NHANES). MUHP was classified as having > three metabolic abnormalities. Coffee consumption was not associated with metabolic phenotypes, but negatively correlated with several metabolic variables, including BMI (p < 0.001). Plasma folate was positively associated with MUHP (p < 0.004), while vit. B12 was inversely associated with MUHP (p < 0.035). Our results suggest the potential protective impact of coffee on individual components of MetS and indicate a positive correlation between coffee consumption and MUHP among overweight individuals. Identifying possible dietary factors may provide practical and low-cost dietary intervention targets, specifically for early intervention. Larger and randomized intervention studies and prospective longitudinal studies are required to further evaluate these associations.

Impact of Metabolic Syndrome Components in High-Risk Cardiovascular Disease Development in Older Adults

OBJECTIVE

Analyze the influence between the components of metabolic syndrome and the independent risk for cardiovascular disease (CVD) in the elderly.

METHODS

A descriptive cross-sectional study was carried out with 205 older adults from a primary healthcare unit of the Federal District, Brazil. The cardiovascular risk was determined by the Framingham Risk Score (FRS). The National Cholesterol Evaluation Program for Adult Treatment Panel III 2001 (NCEP-ATP III) criteria were considered to analyze metabolic syndrome (MS) diagnoses.

RESULTS

There was a strong association between MS and high cardiovascular risk (OR = 8.86). The univariate analysis main findings revealed that male gender, diabetes, smoking habit, systolic blood pressure, HDL level, high blood glucose, glycated hemoglobin, and LDL level were associated with high cardiovascular risk. FRS increases significantly with the presence of four or more MS components (by 30%, if 4 components are present, and by 40%, if 5 components) when compared with the presence of three or fewer components (P <0.001). A logistic regression analysis of high-risk predictors was described to reduce the effects of confounding and bias factors.

CONCLUSION

The identification of MS associated with high FRS values represents a cascading of adverse effects on the population's aging process.

Genetic markers and continuity of healthy metabolic status: Tehran cardio-metabolic genetic study (TCGS)

Obese individuals can be categorized as “healthy obese” (MHO) and “unhealthy obese” (MUO) based on the presence or absence of metabolic abnormality. This study sets out to assess potential genetic causes behind persistence of healthy metabolic status in individuals categorized as “healthy obese”. This study was conducted in the framework of the Tehran cardio-metabolic genetic study (TCGS). 766 MHO subjects at the start of the study followed up 15 years for occurrence of metabolic unhealthy status. These two groups (persistent MHO, MUO) were compared regarding the presence or absence of 16 single nucleotide polymorphisms (SNPs) identified as being associated with obesity phenotype in previous studies. We used logistic regression model for assessing the association between MHO/MUO with candidate SNPs. By the end of the follow up, 206 (27%) were categorized as the persistent MHO and 560 (73%) as MUO groups. Considering interaction effect between some SNP and sex, a sex stratification analysis was applied. When the analysis was performed by gender, rs1121980 associated with a decrease, and rs7903146 with an increase in the likelihood of persistent MHO individuals. Another analysis was separately performed on postmenopausal women from both groups; it showed that rs13107325 was associated with an increase in the likelihood of persistent MHO status in this subgroup of woman. In all cases, the markers had dominant inheritance. This findings suggest that the expression of some genetic markers are associated with persistence of healthy metabolic status, in female obese individuals.

Dietary determinants of unhealthy metabolic phenotype in normal weight and overweight/obese adults: results of a prospective study

We aimed to investigate associations of dietary intakes with unhealthy metabolic phenotype development, in normal weight and overweight/obese adults separately. A total of 1114 individuals, aged ≥19 years, with healthy phenotype in the third examination cycle of Tehran Lipid and Glucose Study were followed until the fifth examination. Dietary intakes were estimated using the food frequency questionnaires, collected during the study. The participants were grouped as normal weight and overweight/obese according to the baseline body mass index (BMI). Unhealthy metabolic status was determined as having more than one component of metabolic syndrome using the Joint Interim Statement. Regardless of BMI, higher intakes of magnesium, dairy products, poultry, apples/pears, citrus fruits, and tea/coffee decreased the risk of developing unhealthy phenotype, while higher intakes of fast foods, organ meats, and potatoes increased the risk. Food intake can influence the transition to unhealthy phenotype in metabolically healthy adults, irrespective of the BMI status.

Metabolic Unhealthiness Increases the Likelihood of Having Metabolic Syndrome Components in Normoweight Young Adults

Findings on risk detection for having metabolic syndrome (MetS) components, each of which may individually increase the risk of disease and mortality, are limited in young adults. In this study, we aimed to calculate the likelihood of having ≥1 MetS component in normoweight young adults using two different metabolic health criteria. We recruited 1182 normoweight young adults from the Taiwan Survey on the Prevalence of Hypertension, Hyperglycemia, and Hyperlipidemia and the National Health Interview Survey (aged 16–45 years, 39% male, body mass index = 18.5–22.99, all without MetS) and followed them for 5 years. Metabolic health criteria were derived from the Harmonized criteria (unhealthy if showing abnormality in one or two MetS components) and the triglyceride-glucose index (TyG-i; unhealthy if TyG-i was in the >75th percentile). Odds ratio (OR) and 95% confidence interval (CI) estimations for having ≥1 MetS component and for having each MetS component in 5 years were assessed using multivariable-adjusted logistic regression. We observed a significantly increased likelihood of the presence of ≥1 MetS component in the unhealthy group by using the Harmonized criteria and TyG-i (adjusted OR (aOR); 95%CI: 2.64; 2.02–3.45 and 2.1; 1.57–2.82, respectively). The areas under the receiver-operating characteristics curves were 0.679 and 0.652 for the final models using Harmonized and TyG-i criteria, respectively. These findings support the recommendation of treating any metabolic component abnormality, even in young adults without a MetS diagnosis.

Metabolic Syndrome: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

In recent decades, investigations have been focused on the definition, incidence and predictors of metabolic syndrome (MetS) in Iranians. This study aimed to review systematically investigations on MetS, conducted among the Tehran lipid and glucose study (TLGS) participants.

EVIDENCE ACQUISITION

Literature on MetS documented by TLGS studies published from 2000 to 2017 were searched using Pubmed and Scopus database in English language with a combination of following keywords: Metabolic syndrome, TLGS.

RESULTS

The harmonized definition of MetS was confirmed, based on the estimated cut point of waist circumference (WC) ≥ 95 cm for both genders in Iran. The incidence rate was 550.9/10000 person/years, lower among women (433.5/10000) than men (749.2/10000). The prevalence of abdominal obesity, high triglycerides (TG), low high density lipoprotein cholesterol (HDL-C), high blood pressure (BP), and high fasting blood glucose (FBG) was 30, 46, 69, 34, and 12%, respectively. The prevalence of MetS in adolescents was 10.1% with no significant difference between boys and girls (10.3% in boys and 9.9% in girls). A strong association of WC (OR: 2.32, CI: 2.06 - 2.59) and TGs (OR: 1.95, CI: 1.65 - 2.11) with development of MetS was found. In adolescent boys, WC had the highest OR for MetS risk. WHO-defined MetS was a significant predictor of total and cardiovascular mortality both in men (HR: 1.66, CI: 1.23 - 2.24; HR:1.93, CI: 1.26 - 2.94) and women (HR: 2.01, CI: 1.39 - 2.88; HR:2.71, CI: 1.44 - 5.09).

CONCLUSIONS

Our results indicate high incidence of MetS in Tehranian adults and adolescents; high WC also appears to be a strong predictor of MetS. All definitions of MetS predicted cardiovascular disease.

Overweight and Obesity: Findings from 20 Years of the Tehran Lipid and Glucose Study

CONTEXT

The prevalence of overweight and obesity are increasing worldwide and have frequently been associated with health risks. This review highlighted several studies regarding obesity, outlining contributions of over a span of almost two decades in the Tehran Lipid and Glucose Study (TLGS).

EVIDENCE ACQUISITION

A systematic review was undertaken to retrieve articles related to all aspects of obesity from the earliest available date up to January 30, 2017.

RESULTS

Prevalence of excess weight, including overweight and obesity were 20.8 and 63.6% among those aged below and above 20 years, respectively. TLGS found a high incidence of obesity with higher incidence in women among Tehranian adults; the cumulative incidence of obesity was 31.3, 38.1 and 23.4% for the whole population, women, and men, respectively. In children and adolescents, younger non-obese 7 - 9 years old, compared to 10 - 11 year olds are at greater risk of obesity. Prevalences of abdominal obesity in men and women were 52.8% and 44.4% respectively. Similar to generalized obesity, a high incidence of abdominal obesity was observed; the total cumulative incidence of abdominal obesity was 76.0% (83.6% for men and 70.9% for women). Metabolically healthy obese (MHO) and metabolically healthy abdominal obese (MHAO) are two important obesity phenotypes. People with these phenotypes have different risks for cardiovascular disease (CVD), type 2 diabetes (T2DM), and mortality. In the TLGS participants, MHO was found in 2% and 7.7% of the whole and obese population, respectively, whereas MHAO phenotype was reported in 12.4% and 23.5% of the whole and abdominal obese population. In these unstable conditions, during the long term follow up the metabolic risks developed in nearly half of the individuals. During a 12-year follow-up, incident CVD did not increase in the MHO phenotype compared to metabolically healthy normal weight (MHNW) individuals, but the risk of CVD events had increased in all metabolically unhealthy phenotypes. However in another report, over a 10-year follow-up, MHAO phenotype had an increased risk for CVD in comparison to the reference group, metabolically healthy non-abdominal obese (MHNAO) individuals.

CONCLUSIONS

The TLGS studies bridged the significant gap in knowledge regarding prevalence, incidence, trends, morbidities and mortalities for obesity among Iranian population.

Contributions and Implications of the Tehran Lipid and Glucose Study

Tehran Lipid and Glucose Study (TLGS), an epidemiological study of non-communicable disease with 20 years follow up in a developing country in nutrition transition is a unique study in 15000 family based individuals, 3 - 75 years of age in a part of large city of Tehran. The success rate of recruitment for 20 years, intervention for lifestyle change, and thyroid, reproduction and cardiometabolic genetic studies derived from TLGS have paved suitable path towards precision medicine. In this review, baseline findings and changes of risk factors for the development of NCD including body weight, nutrition, physical activity, blood pressure, tobacco smoking, serum glucose and serum lipids as well as metabolic syndrome, chronic kidney disease, quality of life and biochemical findings in TLGS cohort have been summarized. The results of community based intervention for lifestyle change caused decreases in the prevalence of metabolic syndrome and the incidence of diabetes. It is concluded that TLGS has served as a model for other cohort studies in Iran and the region; it has helped to mobilize scientists in developing countries; it has established locally needed definitions of NCD variables; has served as a model for cohort studies in developing countries in nutrition transition with all socioeconomic constraints and has helped manpower education and development of local CVD risk scores for implementation of NCD management.

Longitudinal associations of high-density lipoprotein cholesterol or low-density lipoprotein cholesterol with metabolic syndrome in the Chinese population: a prospective cohort study

OBJECTIVE

Currently, most studies only reveal the relationship between baseline high-density lipoprotein cholesterol (HDL-c) or low-density lipoprotein cholesterol (LDL-c) levels and metabolic syndrome (MetS). The relationship between dynamic changes in HDL-c or LDL-c and MetS remains unclear. We aimed to gain a deeper understanding of the relationship between the dynamic changes in HDL-c or LDL-c and MetS.

DESIGN

A prospective study.

SETTING

The Medical Centre of the Second Hospital affiliated with Dalian Medical University from 2010 to 2016.

PARTICIPANTS

A total of 4542 individuals who were initially MetS-free and completed at least two follow-up examinations as part of the longitudinal population were included.

METHODS

The Joint Interim Statement criteria 2009 were used to define MetS. We used the Joint model to estimate the relative risks (RRs) of incident MetS.

RESULTS

The cumulative incidence of MetS was 17.81% and was 14.86% in men and 5.36% in women during the 7 years of follow-up. In the Joint models, the RRs of the longitudinal decrease in HDL-c and the longitudinal increase in LDL-c for the development of MetS were 18.8781-fold (95% CI 12.5156 to 28.4900) and 1.3929-fold (95% CI 1.2283 to 1.5795), respectively.

CONCLUSIONS

The results highlight that the dynamic longitudinal decrement of HDL-c or the increment of LDL-c is associated with an elevated risk of MetS.

The dynamic behaviour of metabolic syndrome and its components in an eight-year population-based cohort from the Mediterranean

Background

The significant rise in the prevalence of obesity coincides with the considerable increase in the prevalence of metabolic syndrome (MS) currently being observed worldwide. The components of MS are not static and their dynamics, such as the order of their occurrence, or the time of exposure to them are, as yet, unknown but could well be clinically relevant. Our objective was to study the dynamic behaviour of MS and its components in a large population-based cohort from a Mediterranean region.

Methods and findings

Our study employed a retrospective cohort (between January 1, 2005 and December 31, 2012) made up of individuals from the general population in a region in the northeast of Catalonia, Spain. Given that most of the explicative variables of the risk of having MS were time dependent and, therefore, the risk was not proportional, we used the Andersen-Gill (AG) model to perform a multivariate survival analysis and inferences were performed using a Bayesian framework.

Thirty-nine percent of the participants developed MS; 44.6% of them with a single limited episode. Triglycerides and low HDL cholesterol, together with obesity, are components associated with the first occurrence of MS. Components related to the metabolism of glucose are associated with a medium risk of having a first episode of MS, and those related to blood pressure are associated with a lower risk. When the components related to blood pressure and the metabolism of glucose appear first, they determine the appearance of the first episode of MS. The variables concerning the persistence of MS are those that correspond to clinical conditions that do not have well-established drug treatment criteria.

Conclusions

Our results suggest that the components related to the metabolism of glucose and to high blood pressure appear early on and act as biomarkers for predicting MS, while the components related to obesity and dyslipidaemia, although essential for the development of MS, appear later. Making lifestyle changes reduces the conditions associated with the persistence of MS.

Predictors of incident obesity phenotype in nonobese healthy adults

BACKGROUND

Despite their different cardiovascular consequences, little is known about predictors of metabolically healthy (MHO) and metabolically unhealthy obesity (MUHO). This cohort study was designed to address this question in participants of the Tehran Lipid and Glucose Study.

MATERIALS AND METHODS

Employing the Joint Interim Statement (JIS) metabolic syndrome criteria to define MHO/MUHO phenotypes, nonobese, otherwise healthy individuals, aged > 20 years (n = 3489) were recruited and followed up for a median of 13·4 years.

RESULTS

At the follow-up, MHO incidence rate in obese individuals was 36·6%. Comparing MHO vs. MUHO, female gender [odds ratio (OR) = 3·28, 95% confidence interval (CI) 1·27, 8·46)], increased body mass index (BMI; OR = 1·32, 95% CI: 1·12, 1·60) and elevated high-density lipoprotein cholesterol (HDL-C) levels (OR = 1·04, 95% CI: 1·02, 1·07) were related to higher odds of incident MHO, while older age (OR = 0·95, 95% CI: 0·92, 0·98), increased waist circumference (WC; OR = 0·86, 95% CI: 0·81, 0·91), higher WC gain (OR = 0·91, 95% CI: 0·87, 0·95) and increased diastolic blood pressure (DBP; OR = 0·94, 95% CI: 0·91, 0·98) prevented progression towards MHO.

CONCLUSIONS

While baseline BMI and WC were detrimental for developing MHO vs. MUHO, gender was the strongest predictor of incident obesity phenotype in healthy nonobese individuals.

Natural course of metabolically healthy abdominal obese adults after 10 years of follow-up: the Tehran Lipid and Glucose Study

OBJECTIVE

This study aims to assess the natural course of metabolically healthy abdominal obese (MHAO) phenotype and determine the predictors of change in the metabolic status in this population over 10 years of follow-up.

METHODS

A total of 916 MHAO subjects from the Tehran Lipid and Glucose Study were followed for changes in their metabolic health status. Anthropometric and metabolic indices were measured at baseline and were compared between subjects with healthy and unhealthy metabolic conditions at the end of follow-up. Predictors of change in metabolic health were assessed in logistic regression models. National waist circumference cutoffs were used for definition of abdominal obesity. Metabolic health was defined as ⩽1 metabolic components of metabolic syndrome according to the Joint Interim Statement criteria.

RESULTS

At the end of the follow-up, nearly half of the MHAO subjects lost their metabolic health and 42.1% developed metabolic syndrome by definition. Low high-density lipoprotein cholesterol, hypertriglyceridemia and homeostasis model assessment-insulin resistance at baseline were significant predictors of change in metabolic health condition.

CONCLUSION

MHAO is a relatively unstable condition and a considerable percentage of these individuals will lose their metabolic health as time passes. Baseline metabolic characteristics may be useful predictors of this change and should be considered in the care of these individuals.