Defining the metabolic syndrome construct: Multi-Ethnic Study of Atherosclerosis (MESA) cross-sectional analysis

Positive Additive and Multiplicative Interactions among Clustered Components of Metabolic Syndrome with Type 2 Diabetes Mellitus among Brazilian Adolescent Students

Background: It is still controversial whether the joint effect of Metabolic syndrome (MetS) components is greater than that expected based on their independent effects, regarding type 2 diabetes mellitus in adolescents. We evaluated additive and multiplicative interactions between pair-wise combinations of metabolic syndrome components regarding type 2 diabetes mellitus. Methods: We studied 37,815 Brazilian adolescents from a national school-based survey, The Study of Cardiovascular Risk Factors in Adolescents (Portuguese acronym, ERICA). A Poisson regression model was used to calculate sex-, age-, obesity-, smoking status-, sedentary behavior-, physical inactivity-, alcoholic consumption- and socioeconomic status-adjusted prevalence ratios to evaluate both additive and multiplicative interactions. Results: In the comparison of observed and expected joint effects, relative excess risk due to additive interaction (RERI) for high triglycerides and low high-density lipoprotein-cholesterol, high triglycerides and elevated waist circumference, elevated waist circumference and low high-density lipoprotein-cholesterol and elevated waist circumference and high blood pressure were 2.53 (−0.41, 5.46), 2.86 (−2.89, 8.61), 1.71 (−1.05, 4.46) and 0.97 (0.15, 1.79), respectively, thus suggesting additive interactions. Multiplicative interactions for those pairs of components were also observed, as expressed by interaction ratios > 1.0. Conclusions: The joint presence of some of the components of MetS showed a greater association with the prevalence of type 2 diabetes mellitus in adolescents than expected from the sum of their isolated effects. From a public health perspective, preventing one of the components of the pairs that interact may result in a greater reduction in the prevalence of T2DM than focusing on an individual component that does not interact with another component.

Insulin Resistance in Healthy U.S. Adults: Findings from the National Health and Nutrition Examination Survey (NHANES)

BACKGROUND

Insulin is fundamental in two conditions that are epidemic in the United States and globally: obesity and type II diabetes. Given insulin's established mechanistic involvement in energy balance and glucose tolerance, we examined its relationship to common health-related endpoints in a large population-based sample.

METHODS

The National Health and Nutrition Examination Survey is a cross-sectional study that uses a complex multistage probability design to obtain a representative sample of the United States population. Adult participants were included from 8 successive 2-year data waves (1999-2014), including 9,224 normal individuals, 7,699 prediabetic, and 3,413 diabetic subjects. The homeostatic model for insulin resistance (HOMA-IR) was available for 20,336 participants and its relationship with demographic, anthropometric, and clinical data was analyzed. We examined the relationship of HOMA-IR to 8 groups of outcome variables: general health, anthropometric/metabolic [waist size, body mass index (BMI)], cardiovascular (blood pressure), lipid [triglycerides, high-density lipoprotein (HDL)], hepatic [alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT)], hematologic [white blood cells (WBC), hemoglobin (Hgb), platelets], inflammatory (C-reactive protein), and nutritional (vitamins D and C, serum folate, and pyridoxine) variables.

RESULTS

HOMA-IR was generally strongly, monotonically, and highly significantly associated with adjusted outcomes in normal subjects, although clinical laboratory values were generally within normal bounds across insulin quartiles. In the normal subset, the odds ratio and 95% confidence interval for a quartile change in HOMA-IR for obesity (BMI > 30) was 3.62 (3.30-3.97), and for the highest quintile for the triglyceride/HDL the ratio was 2.00 (1.77-2.26), for GGT it was 1.40 (1.24-1.58), and for WBC it was 1.28 (1.16-1.40). The relationship of HOMA-IR to the various outcomes was broadly similar to that observed in prediabetics and diabetics with a few exceptions.

CONCLUSIONS

HOMA-IR levels in a large sample of normal individuals are associated with poorer general health and adverse changes across a wide range of markers. A similar pattern of alterations is observed in prediabetic and diabetic samples.

IMPACT

Clinically, checking insulin levels may be helpful to identify patients that merit further observation and are candidates for early interventions.

High-molecular weight adiponectin/HOMA-IR ratio as a biomarker of metabolic syndrome in urban multiethnic Brazilian subjects

Metabolic syndrome (MetS) has an important epidemiological relevance due to its increasing prevalence and association with type 2 diabetes and cardiovascular disease. Insulin resistance is a core feature of the MetS. HOMA-IR is a robust clinical and epidemiological marker of MetS. Adiponectin is an adipokine with insulin-sensitizing and anti-inflammatory functions; its levels decrease as number of components of MetS increases. High-molecular weight adiponectin (HMWA) is the multimer responsible for the relationship of adiponectin with insulin sensitivity. HOMA-IR and HMWA are suitable candidates for MetS biomarkers. The ratio of adiponectin to HOMA-IR has been validated as a powerful index of MetS and considered a better marker of its presence, than either HOMA-IR or adiponectin alone, in selected homogeneous populations. We compared the strength of association between HMWA, HOMA-IR and HMWA/HOMA-IR ratio with MetS and its key components. Our data have shown that the median (25^th, 75^th percentile) of HMWA/HOMA-IR ratio was lower in subjects with MetS [0.51 (0.33, 1.31)] as compared to those without it [2.19 (1.13, 4.71)]. The correlation coefficient (r) was significantly higher for HMWA/HOMA-IR ratio as compared to HMWA for waist circumference (-0.65; -0.40, respectively); mean blood pressure (-0.27; -0.14, respectively); fasting glucose (-0.38; -0.19, respectively); HDL-cholesterol (0.44; 0.40, respectively); and triglycerides (-0.35; -0.18, respectively). In a multivariable logistic regression analysis, the HMWA/HOMA-IR ratio was a sensitive predictor for MetS, being the only marker that was significantly associated with each and all the individual components of the syndrome. These results expand on previous studies in that we used the active circulating form of adiponectin, i.e. HMWA, and represent a typical Brazilian cohort characterized by intense interethnic admixture. Thus, the HMWA/HOMA-IR ratio is a minimally invasive biomarker for MetS that could be clinically useful in prognosing patient outcome.

Metabolic syndrome, diabetes, and incidence and progression of coronary calcium: the Multiethnic Study of Atherosclerosis study

OBJECTIVES

This study sought to examine and compare the incidence and progression of coronary artery calcium (CAC) among persons with metabolic syndrome (MetS) and diabetes mellitus (DM) versus those with neither condition.

BACKGROUND

MetS and DM are associated with subclinical atherosclerosis as evidenced by CAC.

METHODS

The MESA (Multiethnic Study of Atherosclerosis) included 6,814 African American, Asian, Caucasian, and Hispanic adults 45 to 84 years of age, who were free of cardiovascular disease at baseline. Of these, 5,662 subjects (51% women, mean age 61.0 ± 10.3 years) received baseline and follow-up (mean 2.4 years) cardiac computed tomography scans. We compared the incidence of CAC in 2,927 subjects without CAC at baseline and progression of CAC in 2,735 subjects with CAC at baseline in those with MetS without DM (25.2%), DM without MetS (3.5%), or both DM and MetS (9.0%) to incidence and progression in subjects with neither MetS nor DM (58%). Progression of CAC was also examined in relation to coronary heart disease events over an additional 4.9 years.

RESULTS

Relative to those with neither MetS nor DM, adjusted relative risks (95% confidence intervals [CI]) for incident CAC were 1.7 (95% CI: 1.4 to 2.0), 1.9 (95% CI: 1.4 to 2.4), and 1.8 (95% CI: 1.4 to 2.2) (all p < 0.01), and absolute differences in mean progression (volume score) were 7.8 (95% CI: 4.0 to 11.6; p < 0.01), 11.6 (95% CI: 2.7 to 20.5; p < 0.05), and 22.6 (95% CI: 17.2 to 27.9; p < 0.01) for those with MetS without DM, DM without MetS, and both DM and MetS, respectively. Similar findings were seen in analysis using Agatston calcium score. In addition, progression predicted coronary heart disease events in those with MetS without DM (adjusted hazard ratio: 4.1, 95% CI: 2.0 to 8.5, p < 0.01) and DM (adjusted hazard ratio: 4.9 [95% CI: 1.3 to 18.4], p < 0.05) among those in the highest tertile of CAC increase versus no increase.

CONCLUSIONS

Individuals with MetS and DM have a greater incidence and absolute progression of CAC compared with individuals without these conditions, with progression also predicting coronary heart disease events in those with MetS and DM.

Prevalence of metabolic syndrome and related metabolic traits in an island population of the Adriatic

BACKGROUND

Metabolic syndrome, a constellation of risk factors associated with cardiovascular disease and Type 2 diabetes, has reached epidemic proportions worldwide. Epidemiological studies in transitional societies will provide insight into the underlying factors that interact in its manifestation.

AIMS

To estimate the prevalence of metabolic syndrome, provide a comparative analysis of two metabolic syndrome definitions and assess clustering and association of metabolic traits and cardiovascular diseases in an Adriatic island population.

SUBJECTS AND METHODS

In a cross-sectional study, data on four anthropometric, blood pressure and 11 biochemical traits were obtained from 1430 adults from the island of Hvar.

RESULTS

Prevalence of metabolic syndrome was 25% and 38.5% based on Adult Treatment Panel III and International Diabetes Federation definitions, respectively. Rates of abdominal obesity, elevated blood glucose and hypertension were high. Among the traits not included in the definitions, levels of LDL, total cholesterol and fibrinogen were markedly elevated. The majority of the phenotypes were significantly associated with the syndrome, the strongest being waist circumference.

CONCLUSION

The Croatian islanders are characterized by a high prevalence of metabolic abnormalities. Central obesity is the strongest contributor of the syndrome. With a high prevalence of dyslipidemia and pro-inflammatory factors, the population is at substantial risk for cardiovascular diseases.

A bivariate genome-wide approach to metabolic syndrome: STAMPEED consortium

OBJECTIVE The metabolic syndrome (MetS) is defined as concomitant disorders of lipid and glucose metabolism, central obesity, and high blood pressure, with an increased risk of type 2 diabetes and cardiovascular disease. This study tests whether common genetic variants with pleiotropic effects account for some of the correlated architecture among five metabolic phenotypes that define MetS. RESEARCH DESIGN AND METHODS Seven studies of the STAMPEED consortium, comprising 22,161 participants of European ancestry, underwent genome-wide association analyses of metabolic traits using a panel of ∼2.5 million imputed single nucleotide polymorphisms (SNPs). Phenotypes were defined by the National Cholesterol Education Program (NCEP) criteria for MetS in pairwise combinations. Individuals exceeding the NCEP thresholds for both traits of a pair were considered affected. RESULTS Twenty-nine common variants were associated with MetS or a pair of traits. Variants in the genes LPL, CETP, APOA5 (and its cluster), GCKR (and its cluster), LIPC, TRIB1, LOC100128354/MTNR1B, ABCB11, and LOC100129150 were further tested for their association with individual qualitative and quantitative traits. None of the 16 top SNPs (one per gene) associated simultaneously with more than two individual traits. Of them 11 variants showed nominal associations with MetS per se. The effects of 16 top SNPs on the quantitative traits were relatively small, together explaining from ∼9% of the variance in triglycerides, 5.8% of high-density lipoprotein cholesterol, 3.6% of fasting glucose, and 1.4% of systolic blood pressure. CONCLUSIONS Qualitative and quantitative pleiotropic tests on pairs of traits indicate that a small portion of the covariation in these traits can be explained by the reported common genetic variants.

Understanding diabetes in patients with HIV/AIDS

This paper reviews the incidence, pathogenetic mechanisms and management strategies of diabetes mellitus in patients with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). It classifies patients based on the aetiopathogenetic mechanisms, and proposes rational methods of management of the condition, based on aetiopathogenesis and concomitant pharmacotherapy.

Metabolic syndrome and angiographic coronary artery disease prevalence in association with the Framingham risk score

BACKGROUND

The association of metabolic syndrome with coronary artery disease (CAD) has been studied extensively. However, little is known about the effect of Framingham risk score (FRS) and metabolic syndrome components on the association of metabolic syndrome with angiographically significant CAD. Our aim was to investigate whether that relationship is influenced by individual's 10-year CAD risk profile as assessed by FRS. Furthermore, we sought to elucidate whether metabolic syndrome is associated with angiographically significant CAD independently of its individual components.

METHODS

We studied a consecutive sample of 150 patients undergoing coronary angiography for the evaluation of chest pain. Metabolic syndrome was defined according to the revised National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria, and the 10-year CAD risk was estimated by the FRS.

RESULTS

Metabolic syndrome patients had a 2-fold higher CAD prevalence compared to those without metabolic syndrome [odds ratio (OR), 2.004; 95% confidence interval (CI), 1.029-3.905] but this finding was attenuated after adjustment for FRS (OR, 1.770; 95% CI, 0.872-3.594). Stratification of patients into three groups according to FRS revealed that metabolic syndrome predictive ability was confined in those being at <10% 10-year CAD risk. Including metabolic syndrome and its individual components into the same logistic regression model, only the glucose criterion was an independent predictor of angiographically significant CAD (OR, 4.137; 95% CI, 1.477-11.583).

CONCLUSIONS

Metabolic syndrome is an independent determinant of angiographically significant CAD only among those individuals at low 10-year risk for future coronary events. Individual components of the syndrome, such as impaired fasting glucose, have a stronger association with CAD than the syndrome as a whole.

Effect of recreational physical activity on insulin levels in Mexican/Hispanic children

The effect of increased recreational physical activity in children on insulin levels has not yet been studied. We carried out a randomized controlled trial in 76 children 6-9 years old, 32 of them increased their physical activity and 30 maintained the same level. In the intervention group, after a week of baseline, recreational activity three times/week was programmed for 12 weeks. We compared insulin, homeostatic model assessment (HOMA) index, glucose, HDL-C, LDL-C, triglycerides, and body mass index in both groups. Thereafter, we compared groups of normal weight, overweight, and with obesity in the experimental group. The group of recreational activity increased their median daily steps (15,329 to 19,910) and decreased insulin (p < 0.001) and HOMA index (4.36 vs. 2.39, p < 0.001). The diminution of insulin levels was more significant in the overweight group (p < 0.007). In conclusion, in our group, children who increased physical activity during 12 weeks decrease insulin levels and insulin resistance without change in other metabolic and anthropometric variables.

Association between metabolic syndrome and carotid atherosclerosis in individuals without diabetes based on the oral glucose tolerance test

INTRODUCTION

Whether or not metabolic syndrome is predictive of atherosclerotic disorders may depend on the population studied. We investigated whether metabolic syndrome is associated with carotid atherosclerosis in individuals who were shown not to have diabetes mellitus based on results of the 75-g oral glucose tolerance test (OGTT).

METHODS AND RESULTS

Between 1994 and 2003, 3904 individuals underwent general health screening that included the OGTT. Among these 3904 individuals, 3679 had a fasting plasma glucose of <126 mg/dL (subgroup 1), and 3488 had a 2-h post-OGTT glucose value of <200mg/dL (subgroup 2). In both subgroups, metabolic syndrome was found to be a risk factor for carotid plaque and for carotid intima-media thickening in men, and tended to be a risk factor for carotid plaque in women after adjustment for age. Among 3473 individuals who had both a fasting plasma glucose value of <126 mg/dL and a 2-h post-OGTT glucose of <200mg/dL, 2440 did not have hypertension, which was defined as systolic and diastolic blood pressure of <140/90 mmHg and absence of use of anti-hypertensive medication. In these non-diabetic non-hypertensive individuals, the association between metabolic syndrome and carotid plaque or carotid intima-media thickening was not statistically significant even with adjustment only for age.

CONCLUSIONS

In men who did not have impaired fasting glycemia and/or in those without impaired glucose tolerance, metabolic syndrome was a predictor of carotid atherosclerosis after age adjustment, although metabolic syndrome was not found to be a predictor of carotid atherosclerosis when hypertensive individuals were excluded from the study population.