Design and validation of a population-based definition of the metabolic syndrome

Recent advances in managing/understanding the metabolic syndrome

The metabolic syndrome (MetS) concept gathers in a single entity a set of metabolic abnormalities that have in common a close relationship with ectopic deposit of lipids, insulin resistance, and chronic low-grade inflammation. It is a valuable teaching tool to help health professionals to understand and integrate the consequences of lipotoxicity and the adverse metabolic consequences of insulin resistance. Also, it is useful to identify subjects with a high risk for having incident type 2 diabetes. Systems biology studies have gained a prominent role in understanding the interaction between adipose tissue dysfunction, insulin action, and the MetS traits and co-morbidities (that is, non-alcoholic steatohepatitis, or NASH). This approach may allow the identification of new therapeutic targets (that is, de novo lipogenesis inhibitors for NASH). Treatment targets on MetS are the adoption of a healthy lifestyle, weight loss, and the control of the co-morbidities (hyperglycemia, dyslipidemia, arterial hypertension, among others). The long-term goals are the prevention of type 2 diabetes, cardiovascular events, and other MetS-related outcomes. In the last few decades, new drugs derived from the identification of innovative treatment targets have come on the market. These drugs have positive effects on more than one MetS component (that is, hyperglycemia and weight control). New potential treatment targets are under study.

Validation of continuous clinical indices of cardiometabolic risk in a cohort of Australian adults

BACKGROUND

Indicators of cardiometabolic risk typically include non-clinical factors (e.g., smoking). While the incorporation of non-clinical factors can improve absolute risk prediction, it is impossible to study the contribution of non-clinical factors when they are both predictors and part of the outcome measure. Metabolic syndrome, incorporating only clinical measures, seems a solution yet provides no information on risk severity. The aims of this study were: 1) to construct two continuous clinical indices of cardiometabolic risk (cCICRs), and assess their accuracy in predicting 10-year incident cardiovascular disease and/or type 2 diabetes; and 2) to compare the predictive accuracies of these cCICRs with existing risk indicators that incorporate non-clinical factors (Framingham Risk Scores).

METHODS

Data from a population-based biomedical cohort (n = 4056) were used to construct two cCICRs from waist circumference, mean arteriole pressure, fasting glucose, triglycerides and high density lipoprotein: 1) the mean of standardised risk factors (cCICR-Z); and 2) the weighted mean of the two first principal components from principal component analysis (cCICR-PCA). The predictive accuracies of the two cCICRs and the Framingham Risk Scores were assessed and compared using ROC curves.

RESULTS

Both cCICRs demonstrated moderate accuracy (AUCs 0.72 - 0.76) in predicting incident cardiovascular disease and/or type 2 diabetes, among men and women. There were no significant differences between the predictive accuracies of the cCICRs and the Framingham Risk Scores.

CONCLUSIONS

cCICRs may be useful in research investigating associations between non-clinical factors and health by providing suitable alternatives to current risk indicators which include non-clinical factors.

Prehypertension in a Mexican population: influence of age, gender, and body fat

We studied the association of age, gender, and distribution of body fat with prehypertension in a sample of Mexican adults. This study was performed in a sample of 900 adults (275 men and 625 women), with the median age of 42 years. Resting blood pressure was measured in duplicate, and prehypertension and hypertension were defined according to JNC 7 criteria. The prevalence of hypertension and prehypertension in our population was 11.56% and 26.5%, respectively. The prevalence of prehypertension was significantly higher in men than in women. Prehypertension was associated with middle and old age (odds ratio [OR] = 2.6 and 2.4, respectively, P < .001), abdominal obesity (OR = 1.3, P = .008), upper quintiles of body mass index (OR = 2.05, P = .005), waist (OR = 1.97, P = .01) and hip (OR = 2.04, P = .005) circumferences, and body fat (OR = 2.37, P = .001). The main factors associated with the development of prehypertension are age, central obesity, and body fat.

Oxidative stress-induced risk factors associated with the metabolic syndrome: a unifying hypothesis

Although the biochemical steps linking insulin resistance with the metabolic syndrome have not been completely clarified, mounting experimental and clinical evidence indicate oxidative stress as an attractive candidate for a central pathogenic role since it potentially explains the appearance of all risk factors and supports the clinical manifestations. In fact, metabolic syndrome patients exhibit activation of biochemical pathways leading to increased delivery of reactive oxygen species, decreased antioxidant protection and increased lipid peroxidation. The described associations between increased abdominal fat storage, liver steatosis and systemic oxidative stress, the diminished concentration of nitric oxide derivatives and antioxidant vitamins and the endothelial oxidative damages observed in subjects with the metabolic syndrome definitively support oxidative stress as the common second-level event in a unifying pathogenic view. Moreover, it has been observed that oxidative stress regulates the expression of genes governing lipid and glucose metabolism through activation or inhibition of intracellular sensors. Diet constituents can modulate redox reactions and the oxidative stress extent, thus also acting on nuclear gene expression. As a consequence of the food-gene interaction, metabolic syndrome patients may express different disease features and extents according to the different pathways activated by oxidative stress-modulated effectors. This view could also explain family differences and interethnic variations in determining risk factor appearance. This review mechanistically focused on oxidative stress events leading to individual disease factor appearance in metabolic syndrome patients and their setting for a more helpful clinical approach.