Obesity: a main factor of metabolic syndrome?

The metabolic syndrome (MS) is a common metabolic disorder that has been recently related to the increasing prevalence of obesity. The disorder is defined in various ways, but in the near future a new definition(s) will be applicable worldwide. The pathophysiology has been largely attributed, in the past years, to insulin-resistance, even if several epidemiological and pathophysiological data are attractive to indicate visceral obesity as a main factor in the occurrence of the MS, promoting new definitions and re-evaluation of the pathogenesis of this syndrome. In this review, we have analyzed the role of visceral obesity in the new definition of the MS such as the pathophysiological role of the abnormal fat distribution in the occurrence of this syndrome. In view of this, relationships between visceral obesity, free fatty acids, dyslipidaemia and insulin-resistance have been reported. In addition, the effects of some adipocytokines and other proinflammatory factors produced by fat accumulation on the appearance of the MS have been also emphasized. Finally, according to recommendations of several international societies, the role of the life-style change and of the weight loss in the prevention and treatment both of obesity and of other associated risk factors has been analyzed.     

Alcohol consumption and metabolic syndrome: does the type of beverage matter?

OBJECTIVE: To examine the association between total and beverage-specific alcohol consumption and the prevalence odds of metabolic syndrome (MS). RESEARCH METHODS AND PROCEDURES: Using a cross-sectional design, we studied 4510 white participants of the National Heart, Lung, and Blood Institute Family Heart Study. We used generalized estimating equations adjusting for age, education, risk group, smoking, physical activity, diabetes mellitus, coronary heart disease, energy intake, energy from fat, fruits, and vegetables, dietary cholesterol, dietary fiber, and use of multivitamins to estimate the prevalence odds of MS by alcohol intake. RESULTS: Compared with never-drinkers, multivariate odds ratios (95% confidence interval) for MS were 1.12 (0.85 to 1.49), 0.68 (0.36 to 1.28), 0.72 (0.50 to 1.03), 0.66 (0.44 to 0.99), and 0.80 (0.55 to 1.16) among men who were former drinkers and who were current drinkers of 0.1 to 2.5, 2.6 to 12.0, 12.1 to 24.0, and >24.0 g/d of alcohol, respectively (p for linear trend 0.018). Corresponding values for women were 0.86 (0.69 to 1.09), 0.80 (0.43 to 1.34), 0.47 (0.33 to 0.66), 0.47 (0.30 to 0.74), and 0.39 (0.21 to 0.74), respectively (p for trend < 0.0001). The reduced prevalence odds of MS was observed across all beverage types: compared with never-drinkers, multivariate adjusted odds ratios (95% confidence interval) of MS were 0.32 (0.14 to 0.73), 0.42 (0.23 to 0.77), 0.57 (0.30 to 1.09), and 0.56 (0.36 to 0.88) for subjects who consumed >7 drinks/wk of wine only, beer only, spirits only, and more than one type of beverage, respectively. DISCUSSION: Our data indicate that alcohol consumption is associated with a lower prevalence of MS irrespective of the type of beverage consumed. Prospective studies are needed to confirm these findings and to assess the influence of drinking patterns on the alcohol-MS association.     

Do health behaviors moderate the effect of socioeconomic status on metabolic syndrome?

PURPOSE: The purpose of this study is to determine whether the effect of socioeconomic factors on metabolic syndrome is influenced by such covariates as health behavior and psychosocial factors. METHODS: This study used data collected from 4400 households during the 2001 Korea National Health and Nutrition Examination Survey. A stratified multistage probability sampling method was applied and the final sample included 6601 subjects older than 20 years who had completed necessary health examinations. RESULTS: The prevalence of metabolic syndrome in Koreans was 25.5% (95% confidence interval [CI], 23.8-27.2) for men and 28.7% (95% CI, 27.2-30.2) for women. Analysis of moderator effects showed that interactions between education and smoking or exercise status and between income and alcohol or smoking status were significant. The significance of the interaction terms indicates that health behavior and psychosocial factors modified the relationship between socioeconomic factors and metabolic syndrome. CONCLUSIONS: Results of this study provide evidence that such behaviors as smoking, drinking alcohol, and insufficient exercise contribute to the incidence of metabolic syndrome. Changes to higher socioeconomic status may not reduce the odds of metabolic syndrome unless behavior also is adapted.     

Non-alcoholic fatty liver: another feature of the metabolic syndrome?

BACKGROUND AND AIMS: Hepatic steatosis and nonalcoholic steatohepatitis (NASH) have been associated with obesity, non insulin-dependent diabetes mellitus and hyperlipidemia. The present study was designed in order to evaluate whether patients with steatosis/NASH presented common features with the metabolic syndrome. METHODS: In 30 patients with nonalcoholic fatty liver the prevalence of hypertension and diabetes; the glucose/insulin profile, lipid profile, and serum leptin were evaluated and correlated with body composition and energy expenditure, assessed by bioimpedance spectroscopy and indirect calorimetry, respectively. Results were compared with a group of eight controls. RESULTS: Obesity was present in 80% of patients, hypertension in 50% and non insulin dependent diabetes in 33%. Glucose metabolism was altered in 69%, with elevated insulin in 14 patients. Serum leptin, higher in women, was increased in patients: 33.9 +/- 38.9 vs 9.6 +/- 6.9 ng/ml, P< 0.05. There was a correlation between insulin and leptin, both of which correlated with body mass index, fat mass and percentage of body fat. Dyslipidaemia was found in 80% of patients: 45% presented low high density lipoproteins cholesterol, 58% high low density lipoproteins and 38% elevated very low density lipoproteins. CONCLUSIONS: There is a strong association between nonalcoholic fatty liver and features of the metabolic syndrome, suggesting a simultaneous insulin resistance and decreased sensitivity to leptin.     

Are metabolic risk factors one unified syndrome? Modeling the structure of the metabolic syndrome X

The metabolic syndrome, manifested by insulin resistance, obesity, dyslipidemia, and hypertension, is conceived to increase the risk for coronary heart disease and type II diabetes. Several studies have used factor analysis to explore its underlying structure among related risk variables but reported different results. Taking a hypothesis-testing approach, this study used confirmatory factor analysis to specify and test the factor structure of the metabolic syndrome. A hierarchical four-factor model, with an overarching metabolic syndrome factor uniting the insulin resistance, obesity, lipid, and blood pressure factors, was proposed and tested with 847 men who participated in the Normative Aging Study between 1987 and 1991. Simultaneous multi-group analyses were also conducted to test the stability of the proposed model across younger and older participants and across individuals with and without cardiovascular disease. The findings demonstrated that the proposed structure was well supported (comparative fit index = 0.97, root mean square error approximation = 0.06) and stable across subgroups. The metabolic syndrome was represented primarily by the insulin resistance and obesity factors, followed by the lipid factor, and, to a lesser extent, the blood pressure factor. This study provides an empirical foundation for conceptualizing and measuring the metabolic syndrome that unites four related components (insulin resistance, obesity, lipids, and blood pressure).     

The metabolic syndrome: is this diagnosis necessary?

Values of insulin-mediated glucose disposal vary continuously throughout a population of apparently healthy persons, and a difference of > or = 600% exists between the most insulin-sensitive and the most insulin-resistant persons. Approximately 50% of this variability can be attributed to differences in adiposity (25%) and fitness (25%), with the remaining 50% likely of genetic origin. The more insulin-resistant a person, the more likely that he or she will develop some degree of glucose intolerance, high triacylglycerol and low HDL concentrations, essential hypertension, and procoagulant and proinflammatory states, all of which increase the risk of cardiovascular disease (CVD). To identify persons at greater CVD risk because of these abnormalities, the World Health Organization, the Adult Treatment Panel III, and the International Diabetes Federation created a new diagnostic category, the metabolic syndrome. Although the components of the 3 versions of the metabolic syndrome are similar, the specific values for those components that define an abnormality are somewhat different, and the manner in which the abnormalities are used to make a positive diagnosis varies dramatically from version to version. This review will summarize the similarities in and differences between the 3 versions of the metabolic syndrome, point out that the clustering of components that make up all 3 definitions of the metabolic syndrome is not accidental and occurs only in insulin-resistant persons, develop the argument that diagnosing the metabolic syndrome in a person has neither pedagogical nor clinical utility, and suggest that the clinical emphasis should be on treating effectively any CVD risk factor that is present.     

Invited commentary: insulin resistance syndrome? Syndrome X? Multiple metabolic syndrome? A syndrome at all? Factor analysis reveals patterns in the fabric of correlated metabolic risk factors

Factor analysis has emerged as a useful method for understanding patterns underlying the co-occurrence of metabolic risk factors for both type 2 diabetes and atherosclerosis--often referred to as "insulin resistance syndrome." In factor analysis of data on 322 healthy elderly people from the Cardiovascular Health Study, Sakkinen et al. (Am J Epidemiol 2000;152:897-907) confirmed findings from a dozen prior studies that as many as four distinct physiologic domains comprise the syndrome, with a unifying role for markers of insulin resistance. With the addition of markers of hemostasis and inflammation, they also found that impaired fibrinolysis and endothelial dysfunction are central features of the syndrome, while inflammation is only weakly linked to insulin resistance through associations with obesity.     

Cushing’s syndrome as a cause of secondary obesity and metabolic syndrome: a case report

We describe the case of a woman affected by morbid obesity associated to type 2 diabetes mellitus (T2DM), hyperlipidaemia and hypertension, configuring a picture of metabolic syndrome (MS). Hormonal investigations revealed that her MS was secondary to the presence of a cortisol-producing left adrenal adenoma. After monolateral adrenalectomy, the MS subsided. Excessive and sustained hypercortisolism gives rise to the entire spectrum of MS. As some clinical manifestations of MS and Cushing’s syndrome (CS) overlap, it is important to consider CS as a possible cause of secondary MS, in order to avoid a delay in diagnosis and proper treatment, which exposes the patient to an increased risk of morbidity and mortality.     

Does a diagnosis of metabolic syndrome have value in clinical practice?

"The metabolic syndrome" is the name for a clustering of risk factors for cardiovascular disease and type 2 diabetes that are of metabolic origin. These risk factors consist of atherogenic dyslipidemia, elevated blood pressure, elevated plasma glucose, a prothrombotic state, and a proinflammatory state. There are 2 major, interacting causes of the metabolic syndrome-obesity and endogenous metabolic susceptibility. The latter typically is manifested by insulin resistance. The metabolic syndrome is accompanied by a 2-fold increase in the risk of cardiovascular disease and a 5-fold increase in the risk of type 2 diabetes. A clinical diagnosis of the metabolic syndrome is useful because it affects therapeutic strategy in patients at higher risk. However, there are 2 views about the best therapeutic strategy for patients with the metabolic syndrome. One view holds that each of the metabolic risk factors should be singled out and treated separately. The other view holds that greater emphasis should be given to implementing therapies that will reduce all of the risk factors simultaneously. The latter approach emphasizes lifestyle therapies (weight reduction and increased exercise), which target all of the risk factors. This approach is also the foundation of other therapies for targeting multiple risk factors together by striking at the underlying causes, as in the development of drugs to promote weight reduction and to reduce insulin resistance. Treating the underlying causes does not rule out the management of individual risk factors, but it will add strength to the control of multiple risk factors.     

Contribution of Swedish moist snuff to the metabolic syndrome: a wolf in sheep's clothing?

AIM: Combined effects of genetic and environmental factors underlie the clustering of cardiovascular risk factors in the metabolic syndrome (MetSy). The aim was to investigate associations between several lifestyle factors and MetSy, with a focus on the possible role of smokeless tobacco in the form of Swedish moist snuff (snus). METHODS: A population-based longitudinal cohort study within the V?sterbotten Intervention Programme in Northern Sweden. All inhabitants at the ages of 30, 40, 50, and 60 are invited to participate in a health survey that includes a questionnaire on psychosocial conditions and lifestyle and measurement of biological variables. Individuals examined in 1990-94 (n = 24,230) and who also returned for follow-up after 10 years were included (total of 16,492 individuals: 46.6% men and 53.4% women). Regression analyses were performed. MetSy was the outcome and analyses were adjusted for age, sex, alcohol abuse, and family history of CVD and diabetes. RESULTS: Ten-year development of MetSy was associated with high-dose consumption of snus at baseline (OR 1.6 [95% CI 1.26-2.15]), low education (2.2 [1.92-2.63]), physical inactivity (1.5 [1.22-1.73]) and former smoking (1.2 [1.06-1.38]). Snus was associated with separate components of MetSy, including triglycerides (1.6, 1.30-1.95), obesity (1.7 [1.36-2.18]) but not hypertension, dysglycemia and low HDL cholesterol. CONCLUSIONS: MetSy is independently associated with high consumption of snus, even when controlling for smoking status. The finding is of public health interest in societies with widespread use of snus. More research is needed to better understand the mechanisms underlying this effect.     

Food patterns and components of the metabolic syndrome in men and women: a cross-sectional study within the Malm? Diet and Cancer cohort.

This study examined the relations between food patterns and five components of the metabolic syndrome in a sample of Swedish men (n = 2,040) and women (n = 2,959) aged 45-68 years who joined the Malm? Diet and Cancer study from November 1991 to February 1994. Baseline examinations included an interview-administered diet history, a self-administered questionnaire, blood pressure and anthropologic measurements, and blood samples donated after an overnight fast. Cluster analysis identified six food patterns for which 43 food group variables were used. Logistic regression analysis was used to examine the risk of each component (hyperinsulinemia, hyperglycemia, hypertension, dyslipidemia, and central obesity) and food patterns, controlling for potential confounders. The study demonstrated relations, independent of specific nutrients, between food patterns and hyperglycemia and central obesity in men and hyperinsulinemia in women. Food patterns dominated by fiber bread provided favorable effects, while food patterns high in refined bread or in cheese, cake, and alcoholic beverages contributed adverse effects. In women, food patterns dominated by milk-fat-based spread showed protective relations with hyperinsulinemia. Relations between risk factors and food patterns may partly depend on gender differences in metabolism or food consumption and on variations in confounders across food patterns.     

Metabolic syndrome in carbon disulfide-poisoned subjects in Korea: does chemical poisoning induce metabolic syndrome?

Objective  Mass carbon disulfide (CS₂) poisoning was reported at a viscose rayon factory in Korea. We evaluated the association between CS₂ poisoning and the prevalence of metabolic syndrome. Methods  The cases (n = 170) involved CS₂-poisoned subjects, who participated in a health examination conducted at a hospital in Korea in 2005. The controls (n = 170) were selected randomly from the participants in the third Korean National Health and Nutrition Examination Survey. Metabolic syndrome was defined as having at least three of following metabolic abnormalities: abdominal obesity, elevated triglyceride, reduced high-density lipoprotein cholesterol, elevated blood pressure, and elevated fasting glucose levels. Results  After adjusting for covariates (age, gender, education, marital status, alcohol consumption, and smoking), CS₂-poisoned subjects had an increased risk of metabolic syndrome (prevalence ratio 1.57, 95% CI 1.25–1.98). Conclusions  The findings suggest that CS₂ poisoning may increase the risk of metabolic syndrome.     

Is non alcoholic steatohepatitis (NASH) part of the metabolic syndrome?

The metabolic syndrome is one of the most common disease of our era that may cause numerous complications. There are some studies showing the need to take attention to the hepatic manifestation of the metabolic syndrome besides its already well-known consequences. In most of the cases there are histopathological evidences for the presence of fatty liver and mainly non alcoholic steatohepatitis. These conditions can lead to hepatic cirrhosis, hepatic failure or even to hepatocellular carcinoma. The risk of these consequences is the greater the more severe the metabolic syndrome is and the more components of it are included. All these emphasise the importance of examining the hepathological status of the patients suffering from the metabolic syndrome.