The metabolic syndrome: Validity and utility of clinical definitions for cardiovascular disease and diabetes risk prediction

The purpose of clinical definitions of the metabolic syndrome is frequently misunderstood. While the metabolic syndrome as a physiological process describes a clustering of numerous age-related metabolic abnormalities that together increase the risk for cardiovascular disease and type 2 diabetes, clinical definitions include obesity which is thought to be a cause rather than a consequence of metabolic disturbance, and several elements that are routinely measured in clinical practice, including high blood pressure, high blood glucose and dyslipidaemia. Obesity is frequently a central player in the development of the metabolic syndrome and should be considered a key component of clinical definitions. Previous clinical definitions have differed in the priority given to obesity. Perhaps more importantly than its role in a clinical definition, however, is obesity in isolation before the hallmarks of metabolic dysfunction that typify the syndrome have developed. This should be treated seriously as an opportunity to prevent the consequences of the global diabetes epidemic now apparent. Clinical definitions were designed to identify a population at high lifetime CVD and type 2 diabetes risk, but in the absence of several major risk factors for each condition, are not optimal risk prediction devices for either. Despite this, the metabolic syndrome has several properties that make it a useful construct, in conjunction with short-term risk prediction algorithms and sound clinical judgement, for the identification of those at high lifetime risk of CVD and diabetes. A recently published consensus definition provides some much needed clarity about what a clinical definition entails. Even this, however, remains a work in progress until more evidence becomes available, particularly in the area of ethnicity-specific waist cut-points.     

The prevalence of the metabolic syndrome in Korean adults: comparison of WHO and NCEP criteria

The aims of this study were to compare the prevalence of the metabolic syndrome according to the WHO and NCEP ATP III criteria in Korean adults, and to compare the prevalence of the metabolic syndrome with the results in previous Korean studies. The study comprised 1,230 subjects (627 men, 603 women) aged 30-79 years (mean 52.4 +/- 10.3 years) who underwent medical check-up from April to June, 2001 in the Korea Association of Health (KAH). The prevalence of the metabolic syndrome according to the modified WHO criteria was 21.8 % of men and 19.4 % of women. However, the prevalence was increased 1.6 times (34.2 % ) in men and 2.0 times (38.7 % ) in women using the modified NCEP criteria. The prevalence of the metabolic syndrome has varied widely according to differences in the criteria. Thus, further studies are necessary to define the appropriate criteria of the metabolic syndrome for Korean adults.     

The association of breast arterial calcification and metabolic syndrome

OBJECTIVES:We investigated the relationship between metabolic syndrome and breast arterial calcification detected via mammography in a cohort of postmenopausal subjects.METHODS:Among 837 patients referred to our radiology department for mammographic screening, 310 postmenopausal females (105 patients with and 205 patients without breast arterial calcification) aged 40 to 73 (mean 55.9±8.4) years were included in this study. The groups were compared with respect to clinical characteristics and metabolic syndrome criteria. Univariate and multivariate analyses identified the factors related to breast arterial calcification.RESULTS:Age, postmenopausal duration and the frequencies of diabetes mellitus, hypertension and metabolic syndrome were significantly higher in the subjects with breast arterial calcification than in those without (p<0.05). Multivariate analysis indicated that age (OR = 1.3, 95% CI = 1.1–1.6, p = 0.001) and metabolic syndrome (OR = 4.0, 95% CI = 1.5−10.4, p = 0.005) were independent predictors of breast arterial calcification detected via mammography. The independent predictors among the features of metabolic syndrome were low levels of high-density lipoproteins (OR = 8.1, 95% CI = 1.0−64.0, p = 0.047) and high blood pressure (OR = 8.7, 95% CI = 1.5−49.7, p = 0.014).CONCLUSIONS:The likelihood of mammographic detection of breast arterial calcification increases with age and in the presence of hypertension or metabolic syndrome. For patients undergoing screening mammography who present with breast arterial calcification, the possibility of metabolic syndrome should be considered. These patients should be informed of their cardiovascular risk factors and counseled on appropriate lifestyle changes.     

Austrian Moderate Altitude Study 2000 (AMAS 2000). The effects of moderate altitude (1,700 m) on cardiovascular and metabolic variables in patients with metabolic syndrome

We investigated the changes in the cardiovascular system [resting blood pressure (BP) and heart rate (HR), measured by means of a 24-h ambulatory BP and a holter-electrocardiogram (ECG)], glycemic parameters, and lipid metabolism of subjects suffering from metabolic syndrome during a 3-week sojourn at 1,700 m in the Austrian Alps. A total of 22 male subjects with metabolic syndrome were selected. Baseline investigations were performed at Innsbruck (500 m above sea level). During the 3-week altitude stay the participants simulated a holiday with moderate sports activities. Examinations were performed on days 1, 4, 9, and 19. After returning to Innsbruck, post-altitude examinations were conducted after 7–10 days and 6–7 weeks, respectively. The 24-h ambulatory BP and holter ECG revealed a decrease in average HR, BP, and rate pressure product (RPP: systolic blood pressure × HR) after 3 weeks of altitude exposure. In some patients, an increase in premature ventricular beats was observed at the end compared to the beginning of the exposure to moderate altitude. The ECG revealed no ischemic ST-segment changes. Maximal physical capacity as measured by symptom-limited maximal cycle ergometry tests remained unchanged during the study. Six weeks after the altitude exposure the blood pressure increased again and returned to pretest levels. The Homeostasis Model Assessment index, which is a measure of insulin resistance, decreased significantly and glucose concentrations obtained after an oral glucose tolerance test were significantly lower after the stay at altitude compared to the basal values. We conclude that after a 3-week exposure to moderate altitude, patients with metabolic syndrome (1) tolerated their sojourn without any physical problems, (2) exhibited short-term favorable effects on the cardiovascular system, and (3) had significant improvements in glycemic parameters that were paralleled by a significant increase in high-density-lipoprotein-cholesterol. Electronic Publication     

Depressive symptoms and sub-clinical atherosclerosis in Africans: role of metabolic syndrome, inflammation and sympathoadrenal function

Depressive symptoms have been consistently associated with sub-clinical atherosclerosis and future risk of coronary heart disease events. However, the pathways linking depression and coronary atherosclerosis are poorly understood. These types of data are particularly sparse in sub-Saharan Africa, which is presently experiencing an exponential rise in CVD. We examined the association between depressive symptoms and mean carotid intima media thickness (mCIMT), and the extent to which this association could be explained by sympathoadrenal function, inflammatory, and metabolic pathways. A sample of 186 black (aged 44.0 ± 8.0 years) and 203 Caucasians (aged 44.8 ± 10.8 years) were recruited as part of the Sympathetic Activity and Ambulatory Blood Pressure in Africans (SABPA) study — presently the only study in sub-Saharan Africa focusing on the contribution of the psychosocial risk factors to cardiovascular health. Depressive symptoms were assessed using the self administered 9-item Patient Health Questionnaire. After adjusting for age, sex, ethnicity, and anti-hypertensive drugs use, participants with severe depressive symptoms had higher mCIMT in comparison to participants with no symptoms (β = 0.038 mm, 95% CI, 0.001 to 0.074 mm). Metabolic syndrome was the only significant mediator of the association between depressive symptoms and mCIMT, and accounted for approximately 21% of the effect. In summary, depressive symptoms were associated with an excess burden of sub-clinical vascular disease. Treatment of metabolic syndrome in patients with depression may partly reduce the risk of sub-clinical vascular disease development.     

Hostility, emotional expression, and hemodynamic responses to laboratory stressors: Reactivity attenuating effects of a tendency to express emotion interpersonally

The present study examined the interactive effects of hostility and a predisposition towards emotional expression or suppression in interpersonal situations. We also attempted to partially replicate findings from a recent investigation which provided evidence of lower myocardial and greater vascular responses in high-hostile relative to low-hostile individuals. Undergraduate students (n = 99) participated in a protocol consisting of rest periods, speech preparation and presentation, a social-evaluative mental arithmetic task, and a stress interview. After classifying participants into high/low hostility by high/low interpersonal emotional expression groups using median-splits, high-hostile individuals showed lower HR and SBP responses to speech preparation and reported greater threat appraisal and negative affect than low-hostile participants. High-hostile interpersonal expressors and male interpersonal expressors displayed lower DBP and TPR reactivity, respectively, than high-hostile or male suppressors. High-hostile expressors also reported lower levels of positive affect than high-hostile suppressors, and expressors reported lower threat appraisals than suppressors, irrespective of hostility. Findings are discussed in terms of an absence of conflict or ambivalence over interpersonal emotional expression for high-hostile expressors and are suggestive of potential health benefits of expressing emotion interpersonally for at-risk groups.     

Association of cortisol and the metabolic syndrome in Korean men and women

Obesity and the metabolic syndrome are closely related and have become increasingly prevalent in Korea. The cardiovascular disease (CVD) risk factors comprising the metabolic syndrome have previously been associated with increased hypothalamic-pituitary-adrenal axis (HPAA) activity, but the associations have not been extensively examined in non-Caucasian populations. The aim of the present study was to investigate the relationships between cortisol, adiposity and the metabolic syndrome in a Korean population. A total of 1,881 adults participated in the study between January 2001 and February 2008. Sociodemographic data were assessed by questionnaires. Body composition, clinic blood pressures as well as metabolic variables including glucose, insulin, and lipid profile were assessed and analyzed in relation to cortisol levels. Mean age of the participants was 58.7 ± 10.8 yr. Higher levels of cortisol was associated with elevated blood pressure, fasting glucose and total cholesterol in men, and between cortisol and systolic blood pressure, fasting glucose and total cholesterol in women. There was an increased risk for the metabolic syndrome associated with higher cortisol levels in both men (P < 0.001) and women (P = 0.040) adjusting for age and body mass index. Higher cortisol levels are associated with several CVD risk factors and the metabolic syndrome, independent of overall of adiposity level, in Korean men and women.     

The effect of physical activity and physical fitness on plasma adiponectin in adults with predisposition to metabolic syndrome

The purpose of this study was to measure changes in plasma adiponectin (ApN) over 24 months of exercise intervention in middle age adults with a predisposition to metabolic syndrome and to determine if changes in ApN were more affected by physical activity or physical fitness. Thirty-six subjects completed a 24 months home-based exercise program (cycling ≥ three times per week, ≥ 45 min/session at 50–65% of VO_2peak). Body composition, blood samples, and physical fitness were studied at baseline and after 12 and 24 months of participation in the study. The prescribed physical activity was monitored via self-reported exercise diary to determine MET levels, hours, and exercise compliance. Two-tailed repeated measures ANOVA and Spearman Rank Correlation Coefficients were used to detect significant differences and associations between the variables. ApN increased significantly (P < 0.05) after 12 months in males (n = 17; 5.3 ± 1.9–7.0 ± 3.0 μg ml⁻¹) but not in females (n = 9; 8.6 ± 3.8–11.5 ± 4.0 μg ml⁻¹). The net change in ApN over 24 months was significantly correlated to the net change in VO_2peak (physical fitness) (r = 0.66; P < 0.001), whereas exercise intensity was negatively correlated to ΔApN over 12 months (r = −0.4; P ≤ 0.04) and 24 months (r = −0.45; P ≤ 0.02). Based on our results, an improvement in cardiorespiratory fitness of 15% increased plasma ApN concentration. Our findings suggest that moderate physical activity performed over many months induces positive changes in the plasma ApN concentration in adults with a predisposition to metabolic syndrome.     

Hostility,coronary heart disease,and total mortality: A 33-year follow-up study of university students

Hostility as measured by the Cook-Medley Hostility (HO) Scale on the Minnesota Multiphasic Personality Inventory has been suggested as a risk factor for coronary heart disease (CHD) and total mortality. This study tested the HO-CHD hypothesis in a sample of 1399 men who entered the University of Minnesota in 1953 and, as part of freshman orientation, completed the MMPI. Current health status was ascertained for 94% of the sample through telephone interviews 33 years later. Higher HO scores did not predict CHD mortality, CHD morbidity, or total mortality either before or after adjustment for baseline risk factors. Among the plausible explanations for these results are that (1) hostility is not a risk factor in all populations, (2) the HO scale at age 19 does not assess a stable psychological characteristic, or (3) the HO scale is not an adequate measure of hostility.This research was supported by a University of Minnesota, School of Public Health, Biomedical Research Support Grant (2S07-RR05448) and the National Heart, Lung, and Blood Institute (2T32-HL07328).     

Hyperinsulinaemia, a key factor of the metabolic syndrome in postmenopausal women

The metabolic syndrome (MetS) is a complex disorder combining obesity, hypertension, atherogenic dyslipidaemia and insulin resistance, a clustering of factors which markedly enhance the risk of developing cardiovascular disease (CVD) and type 2 diabetes. Main features of the MetS, which are found in many postmenopausal women, are increasing prevalence of insulin resistance and obesity (particularly visceral adiposity). Accordingly, a majority of postmenopausal women comply with criteria defining the MetS, and CVD is the first cause of morbidity/mortality in women, occurring even more frequently than in men. Moreover, obesity-related type 2 diabetes approaches pandemic proportions. Simultaneous occurrence of insulin resistance and obesity are most detrimental for metabolic health, and are also associated with increased oxidative stress, inflammatory and prothrombotic processes as well as with postmenopausal alterations in adipocytokine production. Hormone replacement therapy, provided the selected progestin does not antagonize estrogen action, may improve fat mass and distribution, dyslipidaemia and insulin sensitivity in postmenopausal women.     

The relationship between visfatin and metabolic syndrome in postmenopausal women

Objective

The biological role and activity of visfatin, an adipokine mainly produced by visceral fat, has not been fully elucidated. The observed relationships between visfatin and metabolisyndrome are inconsistent. The purpose of this study was to illuminate the relationship between visfatin and metabolic syndrome in postmenopausal women.

Methods

The present study included a sample of 110 postmenopausal Korean women. Subjects with cardiovascular disease or uncontrolled diabetes were excluded from the study sample. Body weight, height, blood pressure (BP), and waist and hip circumference were measured, and biochemical tests were performed.

Results

The mean serum visfatin level (mean ± SD) of subjects with metabolic syndrome was 2.74 ± 1.70 ng/ml. This was significantly higher than the mean level of subjects without metabolic syndrome (p < 0.01). As the number of components of metabolic syndrome increased, the concentration of serum visfatin also increased (p < 0.01). Visfatin concentration was positively correlated with age (r = 0.209, p < 0.05), waist circumference (r = 0.261, p < 0.01), systolic BP (r = 0.255, p < 0.01), diastolic BP (r = 0.252, p < 0.01), fasting glucose level (r = 0.278, p < 0.01), fasting insulin level (r = 0.313, p < 0.01), HOMA-IR (r = 0.345, p < 0.01), total cholesterol level (r = 0.213, p < 0.05), triglyceride level (r = 0.368, p < 0.01), WBC count (r = 0.352, p < 0.01), and homocysteine level (r = 0.196, p < 0.05). Using a multiple logistic regression analysis, visfatin was found to be an independent factor associated with metabolic syndrome after an adjustment for confounding variables including age, body mass index (BMI), and HOMA-IR.

Conclusions

Serum visfatin was associated with metabolic syndrome in postmenopausal women. This suggests that visfatin may act as the underlying pathophysiological trigger for metabolic syndrome in postmenopausal women.     

Hostility and anger expression in African American and European American men is associated with cardiovascular and lipid reactivity

Physiological stress reactivity has been examined with respect to cynical hostility and anger expression, but primarily among Caucasians. Investigations of African Americans are far fewer and have focused only on the cardiovascular system. This study compared the relationships between hostility and anger expression on the one hand, and both cardiovascular and lipid reactivity on the other, among African Americans and European Americans. Forty-six men participated in a study examining cardiovascular and lipid reactivity to a speech stressor. African American men low in cynical hostility had greater blood pressure reactivity to the stressor; this effect appeared to be due primarily to low cynical men with high Anger In. Independent of ethnicity, those with a general tendency to either always express or always inhibit the expression of anger had higher triglyceride reactivity, relative to those with a more flexible style of anger expression. These results suggest that it is important to examine ethnicity in relationship to measures of hostility and anger expression, to uncover vulnerable individuals.     

中国维、汉、哈族成人不同腰围切点代谢综合征的患病率

目的分析我国维吾尔族、汉族及哈萨克族成人不同腰围切点下的代谢综合征（Ms）患病率,探讨不同民族采用适合本民族特点的腰围切点诊断MS的可行性。方法采用分层整群随机抽样方法,对新疆乌鲁木齐市、和田地区及阿勒泰地区维、汉、哈族20～74岁人群进行MS横断面调查。MS诊断以国际糖尿病联盟（IDF）定义为基础,腰围切点根据不同民族区分。结果当腰围切点均为男≥90em和女≥80cm时,维、汉、哈族MS粗患病率分别为42．1％,16．7％和9．5％;年龄标化患病率分别为28．3％,10．5％和5．9％。调整腰围切点为维吾尔族男≥93cm,女I〉89cm;汉族男I〉85cnl,女I〉80cm;哈萨克族男≥99cm,女≥88cm,维、汉、哈族MS粗患病率分别为25．6％,20-3％和6．9％;标化患病率分别为17．6％,13．4％和4．5％。结论根据各民族自身特点调整腰围切点可减少维吾尔族和哈萨克族MS的误诊率,减少汉族MS的漏诊率,维吾尔族与汉族和哈萨克族之间的MS患病率差距缩小。     

Shared genetic variance between the features of the metabolic syndrome: heritability studies

Heritability estimates of MetS range from approximately 10%-30%. The genetic variation that is shared among MetS features can be calculated by genetic correlation coefficients. The objective of this paper is to identify MetS feature as well as MetS related features which have much genetic variation in common, by reviewing the literature regarding genetic correlation coefficients. Identification of features, that have much genetic variation in common, may eventually facilitate the search for pleitropic genetic variants that may explain the clustering of MetS features.A PubMed search with the search terms “(metabolic syndrome OR insulin resistance syndrome) and (heritability OR genetic correlation OR pleiotropy)” was performed. Studies published before 7th July 2011, which presented genetic correlation coefficients between the different MetS features and genetic correlation coefficients of MetS and its features with adipose tissue-, pro-inflammatory and pro-thrombotic biomarkers were included.Nine twin and 19 family studies were included in the review. Genetic correlations varied, but were strongest between waist circumference and HOMA-IR (r²: 0.36 to 0.79, median: 0.50), HDL cholesterol and triglycerides (r²: − 0.05 to − 0.59, median − 0.45), adiponectin and MetS (r²: − 0.32 to − 0.43; median − 0.38), adiponectin and insulin (r²: − 0.10 to − 0.60; median − 0.30) and between adiponectin and HDL-cholesterol (r²: − 0.22 to − 0.51, median − 0.29).In conclusion, heritability studies suggest that genetic pleiotropy exist especially between certain MetS features, as well as between MetS and adiponectin. Further research on actual genetic variants responsible for the genetic pleiotropy of these combinations will provide more insight into the etiology of MetS.     

The metabolic syndrome in relation with the glycemic index and the glycemic load

The metabolic syndrome (MS) is a clustering of metabolic abnormalities that increases the risk to develop chronic diseases such as cardiovascular disease and type 2 diabetes mellitus. Although its precise aetiology is unknown, dietary habits play a major role. Nowadays, more and more attention is paid to the glycemic index (GI) and the glycemic load (GL) of a diet. The GI of a food is a value based on the average increase in blood glucose levels occurring when a 50g carbohydrate portion of that food is consumed. The GL accounts for the amount of carbohydrate per serving.

From reviewing the current literature, we conclude that for healthy and/or overweight subjects the importance of low GI or GL diets in relation to the metabolic syndrome has not been established. One of the reasons is that the diets used in the intervention studies frequently not only differed in GI or GL, but also in fibre, protein and/or fat content. In some of the prospective cohort studies, effects of GI or GL attenuated or even disappeared after correcting for fibre intake. This makes it impossible to ascribe the possible beneficial metabolic effects of low GI or GL diets unequivocally to the GI or GL. The question, therefore, remains open on to what components of the metabolic syndrome are specifically affected by the GI per se. To answer this question, controlled longer-term intervention studies are needed to monitor the effects of the GI on the various components of the metabolic syndrome.     

脂肪因子Chemerin在炎症和代谢综合征中的双重效应

背景：近年多项临床及基础研究显示脂肪因子chemerin与代谢综合征密切相关。 目的：综述脂肪因子chemerin在炎症和肥胖、高血压及糖脂代谢中的作用及机制,概括脂肪因子chemerin与炎症和代谢综合征的关系。 方法：由第一作者检索1990至2014年PubMed数据库以及万方数据库脂肪因子chemerin相关的文献,并进行系统整理、总结和分析。 结果与结论：研究表明脂肪因子chemerin水平与体脂含量、能量代谢、炎症相关,在肥胖和代谢综合征病理生理过程中扮演了重要角色。由于脂肪因子chemerin在炎症和代谢中的双重作用,它可能成为连接慢性炎症和肥胖及其相关疾病的一个关键因子。脂肪因子Chemerin在不同的炎症状态下作用不同,可能与其在不同的炎症环境中裂解方式的不同有关,但并没有明确脂肪因子chemerin在肥胖和代谢综合征中的功能。需要进一步研究明确血清脂肪因子chemerin水平与肥胖和代谢综合征之间的关系。  中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

Polycystic ovary syndrome in post-menopausal women--marker of the metabolic syndrome

OBJECTIVES: To determine among post-menopausal women, the prevalence of polycystic ovary syndrome (PCOS) and to evaluate the endocrine and metabolic profile of these women in comparisons to women without PCOS. METHODS: All women attending two post-menopausal outpatient clinics, fulfilling the inclusion criteria, were evaluated by physical examination, detailed questionnaire and laboratory measurements of glucose, lipids and sex-hormone levels. RESULTS: Among 104 women 7 (6.7%) were diagnosed with PCOS. As compared to women without PCOS, central obesity was more common in the PCOS group (p=0.004), 4/7 had type 2 diabetes compared to 8/97 in the non-PCOS group (p=0.003) and 6/7 versus 31/97 had the characteristic dyslipidemia of the metabolic syndrome (p=0.047). CONCLUSIONS: PCOS is common in post-menopausal women attending outpatient's clinics, and is a marker for a metabolic profile that is associated with a high-risk for cardiovascular diseases (CVD).     

Normal serum aminotransferase levels and the metabolic syndrome: Korean National Health and Nutrition Examination Surveys

Increasing evidence suggests an association between elevated serum aminotransferase level and the metabolic syndrome. However, the significance of relatively low levels of aminotransferase in relation to the metabolic syndrome has not been fully investigated in the general population. We investigated the association between serum amiontransferase level and the metabolic syndrome using data from a nationwide survey in Korea. We measured serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and metabolic conditions among 9771 participants aged 20 or more in the 1998 and 2001 Korean National Health and Nutrition Examination Surveys. Metabolic syndrome was defined according to NCEP-ATP III criteria with a modified waist circumference cutoff (men > 90 cm; women > 80 cm). Serum aminotransferase level, even within normal range, was associated with the metabolic syndrome independent of age, body mass index, waist circumference, smoking, and alcohol intake. Compared with the lowest level (< 20 IU/L), the adjusted odds ratios (95% CI) for an AST level of 20-29, 30-39, 40-49 and > or = 50 IU/L were 1.10 (0.85-1.42), 1.37 (1.02-1.83), 1.62 (1.08-2.43), and 2.25 (1.47-3.44) in men, and 1.18 (0.99-1.41), 1.43 (1.29-1.83), 1.71 (1.09-2.68), and 2.14 (1.20-3.80) in women, respectively. Corresponding odds ratios for ALT levels were 1.27 (0.99-1.63), 1.69 (1.28-2.23), 2.17 (1.58-2.99), and 2.65 (1.96-3.58) in men, and 1.44 (1.22-1.70), 1.65 (1.26-2.15), 2.94 (1.93-4.47), and 2.25 (1.54-3.30) in women, respectively. In conclusion, elevated serum aminotransferase levels, even in the normal to near normal range, are associated with features of the metabolic syndrome.