The metabolic syndrome in Chinese, Malays and Asian Indians. Factor analysis of data from the 1998 Singapore National Health Survey

We used factor analysis to define and compare the manner in which the various features of the metabolic syndrome are linked or clustered in Chinese, Malays and Asian Indians. One thousand nine hundred and fifty seven men (1324 Chinese, 391 Malays and 261 Asian Indians) and 2308 women (1622 Chinese, 391 Malays and 296 Asian Indians) were examined. Anthropometry, blood pressure, serum glucose, lipid concentrations, and serum insulin were measured for all subjects. These data were then subjected to factor analysis which reduced the variables examined to three factors in all ethnic groups and both genders. The first (dyslipidemia) factor was positively loaded for obesity, insulin resistance (IR), fasting triglyceride and negatively loaded for HDL-cholesterol. The second (hyperglycemia) factor was positively loaded for IR and blood glucose. The third (hypertension) factor was positively loaded for obesity and blood pressure. IR was positively loaded in the hypertension factor in Malay women but not in others. Rather than a single entity causally associated with insulin resistance (IR), our findings support a concept in which the metabolic syndrome represents several distinct entities (dyslipidemia, hypertension and hyperglycemia). It appears that Malay females may be more prone to develop hypertension in association with IR.     

多囊卵巢综合征患者胰岛素抵抗与糖脂代谢及性激素的研究

目的通过高胰岛素正葡萄糖钳夹试验评估多囊卵巢综合征(PCOS)患者的胰岛素抵抗,探讨伴胰岛素抵抗PCOS患者糖脂代谢及性激素水平特点。方法将2017年7月至2019年2月就诊于遵义医科大学附属医院内分泌科住院及门诊的73例PCOS患者和体重指数及年龄匹配的27名健康女性行高胰岛素正葡萄糖钳夹试验,根据葡萄糖代谢率、体重指数和稳态模型评估的胰岛素抵抗指数(HOMA-IR)分组,分析PCOS患者糖脂代谢及性激素指标的变化及差异。结果在PCOS组中,糖调节受损者占3.23%(1/31),血脂代谢异常者占9.68%(3/31);而在PCOS合并胰岛素抵抗组中,糖调节受损者占7.14%(3/42),血脂代谢异常者达47.62%(20/42),5例患者被诊断为代谢综合征,占11.90%。相关分析显示,葡萄糖代谢率与体重指数、腰臀比、收缩压、空腹血糖、空腹胰岛素、HOMA-IR、皮质醇、三酰甘油、总胆固醇、低密度脂蛋白胆固醇(LDL-C)、游离雄激素指数(FAI)和谷氨酰转肽酶(GGT)呈负相关(P<0.05),与高密度脂蛋白胆固醇(HDL-C)呈正相关(P=0.028);HOMA-IR与体重指数、腰臀比、收缩压、空腹血糖、空腹胰岛素、HbA1C、LDL-C呈正相关(P<0.05),与葡萄糖代谢率和HDL-C呈负相关(P<0.05);体重指数与腰臀比、收缩压、空腹血糖、空腹胰岛素、HOMA-IR、三酰甘油和LDL-C呈正相关(P<0.05),与葡萄糖代谢率、HDL-C和性激素结合球蛋白(SHBG)呈负相关(P<0.01)。多元线性逐步回归分析表明,体重指数、总胆固醇、三酰甘油和皮质醇是影响葡萄糖代谢率的重要因素,空腹血糖、空腹胰岛素和收缩压是HOMA-IR的重要影响因素,葡萄糖代谢率、HOMA-IR、HDL-C和SHBG仍然是影响体重指数的重要影响因素。结论FAI、SHBG和皮质醇可能参与到PCOS患者的胰岛素抵抗发生中,存在胰岛素抵抗的PCOS患者更容易发生代谢紊乱。     

Adiponectin as a biomarker of the metabolic syndrome.

BACKGROUND: The metabolic syndrome, a cluster of abdominal obesity, dyslipidemia, hypertension and hyperglycemia, is a common basis for atherosclerotic vascular diseases in industrial countries exposed to overnutrition. Adiponectin is an adipose-derived plasma protein with anti-atherogenic and insulin-sensitizing activities. METHODS AND RESULTS: A total of 661 Japanese adults (479 men, 53+/-10 years; 182 women 56+/-10 years) were enrolled. Plasma adiponectin concentrations correlated negatively with waist circumference, visceral fat area, serum triglyceride concentration, fasting plasma glucose, fasting plasma insulin, and systolic and diastolic blood pressure in both sexes. A positive correlation was found between plasma adiponectin and high-density lipoprotein cholesterol concentrations in both sexes. The mean number of components of the metabolic syndrome increased as the plasma adiponectin concentration decreased: 2.57+/-1.34 for men and 2.00+/-1.51 for women with adiponectin concentrations <4.0 microg/ml. In all, 52.3% of men and 37.5% of women with adiponectin concentrations <4.0 microg/ml fulfilled the criteria for metabolic syndrome. CONCLUSION: Hypoadiponectinemia is closely associated with the clinical phenotype of the metabolic syndrome and measuring the plasma concentration of adiponectin may be useful for management of the metabolic syndrome.     

Impact of metabolic syndrome on brachial-ankle pulse wave velocity in Japanese.

The aim of this study was to determine the effect of metabolic syndrome on brachial-ankle pulse wave velocity (baPWV) by using the new guidelines for diagnosis of this syndrome in Japan. We examined 525 men and women without a history of cardiovascular disease or cancer, and an ankle-brachial index < 0.9. The baPWV was measured using a device (Form PWV/ABI) that simultaneously monitored bilateral brachial and ankle pressure wave forms. Metabolic syndrome was defined as a waist circumference > or = 85 (90) cm in men (women) and two or more of the following risk factors: hypertension, dyslipidemia, and glucose intolerance diagnosed by a 75 g oral glucose tolerance test. The baPWV showed a significant linear relationship with waist circumference, waist-to-hip ratio, body fat, systolic and diastolic blood pressure, triglycerides, fasting glucose, 2-h-postload glucose, fasting insulin, and glycosylated hemoglobin-A1c, after adjusting for sex and age. These factors were also strongly related to fasting insulin levels. When subjects were classified into six groups based on waist circumference and the number of risk factors for metabolic syndrome (0, 1, and > or =2), we found that more risk factors clearly increased the odds ratios for an elevated baPWV in those subjects in the highest quartile of the baPWV distribution in multivariate logistic models. An increase in odds ratio was observed despite a normal waist circumference and may well have been due to increased fasting insulin and blood pressure levels. An increase in the number of risk factors for metabolic syndrome was highly correlated with an increased baPWV, probably due to insulin resistance.     

Serum uric acid and leptin levels in metabolic syndrome: a quandary over the role of uric acid

This study investigates the impact of uric acid (UA) on the risk factors associated with metabolic syndrome. In addition, this study explores the relationship between UA and insulin resistance and serum leptin levels in metabolic syndrome. A total of 470 subjects (252 women and 218 men) were recruited from the Department of Health Management at Chang Gung Medical Center (Linkou, Taiwan). Metabolic syndrome was defined using a modified Adult Treatment Panel III (ATP III) definition. The formula for the homeostasis model assessment of insulin resistance (HOMA-IR) is as follows: fasting serum insulin (microU/mL) x fasting plasma glucose (mmol/L)/22.5. Diabetes mellitus was diagnosed in 45 subjects (9.6%); 82 subjects (17.4%) had hypertension. Hyperuricemia was diagnosed in 144 subjects (30.6%). Of these subjects, 115 (63 females and 52 males) (24.5%) were diagnosed as having metabolic syndrome. Patients with hyperuricemia had increased body mass index, waist-to-hip ratio, and triglyceride (Tg) level. The subjects also had lower high-density lipoprotein and greater hypertension. Hormone assays showed an elevation of leptin, immunoreactive insulin (IRI), and HOMA-IR in the hyperuricemia group. Uric acid appeared to be better correlated with Tg, blood pressure (both systolic and diastolic), obesity, immunoreactive insulin, and HOMA-IR. Uric acid did not correlate with leptin or blood glucose levels. Metabolic syndrome and Tg/high-density lipoprotein ratio showed a statistically significant difference in HOMA-IR using 3.8 as a cutoff value. Otherwise, there was no difference in leptin value. In conclusion, serum UA is significantly related to risk factors of metabolic syndrome except for blood glucose. Waist-to-hip ratio and HOMA-IR were statistically different in subjects with and without metabolic syndrome.     

Dissociation between urinary albumin excretion and variables associated with insulin resistance in a healthy population

Objectives. To see if the cluster of metabolic and haemodynamic variables defined as comprising Syndrome X varied as a function of urinary albumin excretion (UAE) rate in a healthy population.
Design. A cross-sectional, population-based study.
Setting. A factory in Italy.
Subjects. Two hundred and twenty-five healthy volunteers, 115 men and 110 women.
Outcome measures. Measurements were made of the plasma glucose and insulin responses to oral glucose, fasting triglyceride (TG) and high density lipoprotein (HDL)-cholesterol concentrations, blood pressure, and UAE rates.
Results. Only five of the 225 volunteers had microalbuminuria, defined as a UAE rate >2 μg min^-1, and the UAE rate was <5 μg min^-1 in 80% of the volunteers. Significant variations in the metabolic and haemodynamic variables measured were not associated with any differences in UAE. Finally, significant relationships were found between various measures of plasma insulin concentration and plasma glucose response to oral glucose, plasma TG and HDL-cholesterol concentrations, and mean arterial blood pressure, independent of variations in age, body mass index, ratio of waist-to-hip girth, and UAE rates.
Conclusion. The widespread variability in plasma glucose and insulin responses, plasma TG and HDL-cholesterol concentrations, and blood pressure that are seen in the population at large cannot be attributed to variations in UAE rate.     

Independent and opposite associations of waist and hip circumferences with diabetes, hypertension and dyslipidemia: the AusDiab Study

OBJECTIVE: Fat distribution as measured by waist-to-hip ratio has been shown to be an important independent predictor of glucose intolerance. Few studies, however, have considered the contributions of the waist and hip circumferences independently. The aim of this study was to investigate the independent associations of waist and hip circumference with diabetes in a large population-based study, and to investigate whether they also apply to other major components of the metabolic syndrome (hypertension and dyslipidemia). In addition, as previous studies were performed in older persons, we investigated whether these associations were present across adult age groups. METHODS: Weight, height, waist and hip circumferences were measured in 11 247 participants of the nationally representative Australian Diabetes, Obesity and Lifestyle (AusDiab) Study. HDL-cholesterol, triglycerides, fasting and 2-h postload glucose were determined, and diastolic and systolic blood pressure was measured. After exclusion of persons already known to have diabetes, hypertension or dyslipidemia, logistic and linear regression were used to study cross-sectional associations of anthropometric variables with newly diagnosed diabetes, hypertension and dyslipidemia, and with continuous metabolic measures, all separately for men (n=3818) and women (n=4582). Analyses were repeated in the same population stratified for age. RESULTS: After adjustment for age, body mass index and waist, a larger hip circumference was associated with a lower prevalence of undiagnosed diabetes (odds ratio (OR) per one s.d. increase in hip circumference 0.55 (95% CI 0.41-0.73) in men and 0.42 (0.27-0.65) in women) and undiagnosed dyslipidemia (OR 0.58 (0.50-0.67) in men and 0.37 (0.30-0.45) in women). Associations with undiagnosed hypertension were weaker (OR 0.80 (0.69-0.93) in men and 0.88 (0.70-1.11) in women). As expected, larger waist circumference was associated with higher prevalence of these conditions. Similar associations were found using continuous metabolic variables as outcomes in linear regression analyses. Height partly explained the negative associations with hip circumference. When these analyses were performed stratified for age, associations became weaker or disappeared in the oldest age groups (age > or =75 y in particular), except for HDL-cholesterol. CONCLUSION: We found independent and opposite associations of waist and hip circumference with diabetes, dyslipidemia and less strongly with hypertension in a large population-based survey. These results emphasize that waist and hip circumference are important predictors for the metabolic syndrome and should both be considered in epidemiological studies. The associations were consistent in all age groups, except in age > or =75 y. Further research should be aimed at verifying hypotheses explaining the 'protective' effect of larger hips.     

2030例急性脑梗死患者合并代谢综合征临床特点分析

目的 观察急性脑梗死患者血脂、血压、腰围和空腹血糖水平,并探讨其代谢综合征的临床特点.方法 回顾性分析2030例急性脑梗死患者的血脂、血压(收缩压、舒张压)、腰围和空腹血糖水平.结果 2030例急性脑梗死住院患者的代谢综合征患病率为67.73%,男性为71.80%,显著高于女性的62.00%(P＜0.001).男性患者高血压、腰围异常、血脂异常和窄腹血糖受损比例均显著高于女性(P＜0.005).代谢综合征以及高血压、腰围异常、血脂异常和空腹血糖受损比例随年龄增大而增高(P＜0.05).结论 脑梗死患者的代谢综合征患病率很高.对脑梗死患者进行代谢综合征评价非常重要,控制血脂异常、高血压、高血糖和肥胖在缺血性卒中的一级和二级预防中均不可忽视.     

Association of white blood cell count and clustered components of metabolic syndrome in Japanese men.

BACKGROUND: The role of inflammation in the genesis of cardiovascular disease has attracted attention and in the present study the association among metabolic syndrome (MS), white blood cell (WBC) count, and insulin concentration was investigated. METHODS AND RESULTS: A cross-sectional study of 3,594 Japanese men aged 34-69 years evaluated the MS components (high blood pressure, hypo-high density lipoprotein (HDL)-cholesterolemia, hypertriglyceridemia, hyperglycemia), as defined by the criteria given in the Third Report of the National Cholesterol Education Program Expert Panel on Detection Evaluation, and Treatment of High Blood Cholesterol in Adults, except for obesity [body mass index (BMI) >/=25 kg/m(2)]. WBC count had a positive correlation with BMI, blood pressure, triglyceride, glucose and insulin, and a negative correlation with HDL-cholesterol. The multi-adjusted means of WBC count and insulin concentration were significantly higher in MS subjects defined as having 3 or more of the components than in non-MS subjects with no more than 2 components. Both means also increased with the number of MS components (p<0.001 for trend). In the multiple linear regression analysis, BMI, HDL-cholesterol, systolic blood pressure, glucose and triglyceride had a significant and independent association with WBC count, but the insulin concentration did not. CONCLUSIONS: The cluster of MS components based on insulin resistance may cause low-grade inflammation.     

Overweight Japanese with body mass indexes of 23.0-24.9 have higher risks for obesity-associated disorders: a comparison of Japanese and Mongolians

OBJECTIVE: The degree of obesity of Asians is less than that of Caucasians. It has been suggested that Japanese, categorized as having normal weight (BMI<25.0), as defined by WHO (2000), have a tendency toward increased incidences of dyslipidemia and diabetes. Our objective was to analyze parameters constituting obesity-associated disorders in overweight Japanese and Mongolians with a body mass index (BMI) of 23.0-24.9, and to assess the suitability for Asians of the Regional Office for Western Pacific Region of WHO criteria pertaining to obesity (WPRO criteria, 2000). DESIGN: Cross-sectional study in a workplace setting. SUBJECTS: A total of 386 Japanese men and 363 Japanese women, and 102 Mongolian men and 155 Mongolian women. MEASUREMENTS: Anthropometric measurements (weight, height, waist circumference, hip circumference and blood pressure) and metabolic measurements (plasma levels of total cholesterol, HDL cholesterol, triglyceride, glucose and insulin). RESULTS: Graded increases in BMI of Japanese and Mongolians were positively associated with body fat percent, waist circumference, hip circumference and waist/hip ratio. The Japanese were categorized as 22% overweight, 22% obese I, 3% obese II; the Mongolians rated as 18% overweight, 34% obese I, 19% obese II, based on the WPRO BMI criteria. The Mongolians had a higher prevalence of obesity and a higher body fat percent, but a lesser gradation of dyslipidemia, than did the BMI-matched Japanese groups. Overweight Japanese (BMI 23.0-24.9), in comparison to normal Japanese (BMI 18.5-22.9), had significant differences in systolic blood pressure, HDL-cholesterol and triglyceride in men, and in systolic and diastolic blood pressure, HDL-cholesterol, triglyceride, insulin and Homoeostasis model assessment-insulin resistance in women. In contrast, the Mongolians showed no significant differences in metabolic parameters between overweight and normal subjects, except for diastolic blood pressure. CONCLUSION: Since the relationship between abdominal fat mass and BMI is ethnic-specific, a universal BMI cutoff point is inappropriate for Asian populations such as the Japanese and Mongolians. The present investigation suggests that, while the WPRO criteria are suitable for Japanese, the WHO criteria are more appropriate for Mongolians.     

Prevalence and risk factors associated with the metabolic syndrome and dyslipidemia in White, Black, Amerindian and Mixed Hispanics in Zulia State, Venezuela

Studies have highlighted the association between insulin resistance (IR) and several cardiovascular (CV) risk factors, including hypertension (HTN), obesity, dyslipidemia (i.e. high triglyceride and low HDL-cholesterol) and glucose intolerance, in a cluster known as the metabolic syndrome (MS). There are few data on the frequency of the MS and dyslipidemia in developing countries, and none in South America. To estimate the prevalence of the MS and its components in Zulia State, Venezuela, and to establish associated demographic and clinical factors, we evaluated 3108 Hispanic men and women aged 20 years or older from a cross-sectional survey of a random representative sample from each health district in Zulia State, Venezuela (1999-2001). Prevalence of the MS and dyslipidemia was defined according to the National Cholesterol Education Program (NCEP)/Adult Treatment Panel III (ATP III) criteria. The age-adjusted prevalence of MS and dyslipidemia was 31.2% and 24.1%, respectively, with higher rates in men than in women. Prevalence rates increased with age and with the degree of obesity. MS prevalence was lower in Amerindian (17.%) compared to Black (27.2%), White (33.3%) and Mixed (37.4%) men, but no differences were found among women. Overall, low HDL-cholesterol (65.3%), abdominal obesity (42.9%) and HTN (38.1%) were the most frequent MS components. After adjusting for age, sex and race groups, family history of diabetes, obesity and HTN were associated with the MS. Sedentary lifestyle also increased the risk of MS, event after adjusting for the same covariates, obesity and the degree of IR. These results suggest that MS is found in approximately one-third of the Venezuelan adult population in Zulia State, with higher prevalence in men related to the presence of dyslipidemia. Lifestyle interventions in MS subjects are needed in Venezuela to halt the burden of CV disease and diabetes.     

Association between fasting glucose and C-reactive protein in a Japanese population: the Minoh study

To investigate the association between fasting glucose and C-reactive protein (CRP), we examined 1715 Japanese individuals (723 men and 992 women) aged 40-69 years who did not have medication for hypertension, diabetes, or dyslipidemia, a history of cardiovascular disease or CRP levels>10mg/l. There was a statistically significant unadjusted correlation between CRP and each component of the metabolic syndrome, including fasting glucose, fasting insulin, body mass index, systolic blood pressure, diastolic blood pressure, high-density lipoprotein cholesterol (negative), and triglycerides in both men and women. With adjustment for age, cigarette smoking, alcohol intake, and other components of the metabolic syndrome, the CRP increments (as back-transformed) compared with the lowest tertile of normal fasting glucose were 0.99, 1.05, 1.21, and 1.34mg/l (P for trend=0.008) with the second lowest and highest tertiles of normal fasting glucose, impaired fasting glucose, and type-2 diabetes, respectively in men. The respective adjusted CRP increments were 1.12, 1.23, 1.33, and 1.93mg/l (P for trend<0.001) in women. In the stratified analyses of CRP levels by sex, obesity status, and fasting glucose category or the number of components of the metabolic syndrome, an increase in CRP levels was greater in women than men with obesity and higher fasting glucose category (gender interaction: P<0.001) or an increased number of components of the metabolic syndrome (gender interaction: P=0.003). These results indicate that CRP levels increase continuously across the spectrum of fasting glucose in both sexes. This association is more pronounced in women.     

The incidence and persistence of the NCEP (National Cholesterol Education Program) metabolic syndrome. The French D.E.S.I.R. study

CONTEXT: In 2001 the "National Cholesterol and Education Program Expert Panel" gave a clinical definition of the metabolic syndrome. The frequency of this syndrome at baseline and its incidence and persistence at three years is studied in a French population. SUBJECTS: 2109 men and 2184 women from the D.E.S.I.R. longitudinal cohort study (Data from an Epidemiological Study on the Insulin Resistance syndrome) in central-western France, aged 30 to 64 years, were examined at inclusion and three years later. METHODS: Evaluation of the frequencies, incidences and persistence of the metabolic syndrome and its abnormalities. This syndrome is defined by the presence of three or more of five abnormalities: waist circumference > 102/88 cm (men/women); triglycerides > o r=1.69 mmol/l, HDL-cholesterol<1.04/1.29 mmol/l (men/women); systolic/diastolic blood pressure > or =130 and/or 85 mmHg; fasting plasma glucose > or =6.1 mmol/l. RESULTS: At baseline, 10% of men and 7% of women had the metabolic syndrome. If the syndrome was defined to include a treatment in the abnormalities (for diabetes, hypertension, dyslipidemia), the syndrome frequencies increased to 16% and 11%. However only 12% and 8% respectively, had this syndrome both at inclusion and at three years. High blood pressure was the most frequent abnormality: 70% and 47% in men and women respectively, at inclusion. The most stable abnormality was high waist circumference (80% persisted), hyperglycaemia the least stable (60% persisted). Hyperinsulinaemia did not cluster closely with this syndrome. CONCLUSIONS: The age-specific frequency of the syndrome is more than 2.5 times higher in the US than in this French cohort and this ratio increased with age. The higher frequencies of abdominal obesity and low HDL-cholesterol in women than in men suggest that these gender-specific thresholds may need to be refined.     

The impact of 3-year changes in lifestyle habits on metabolic syndrome parameters: the D.E.S.I.R study.

BACKGROUND: The effect of lifestyle changes in cohorts of free-living populations has been surprisingly little evaluated. DESIGN: A longitudinal study. METHODS: In the French Data from an Epidemiological Study on the Insulin Resistance (D.E.S.I.R) study of 1958 men and 2028 women, aged 30-65 years, the impact of 3-year changes in lifestyle habits (sporting activity, physical activity at home and at work, alcohol drinking, smoking) on metabolic syndrome parameters [insulin, glucose, high-density lipoprotein (HDL) cholesterol, triglycerides, systolic blood pressure, waist circumference] and on body mass index (BMI) were investigated. RESULTS: In men, 3-year increases in sporting activity were associated with a lowering of insulin, glucose, systolic blood pressure and waist circumference (all P < 0.05). For women, the only effect was on lowering waist circumference (P < 0.03). Increases in physical activity at home were beneficially associated with HDL-cholesterol, triglycerides, waist circumference and BMI changes (all P < 0.05) in men, but had no apparent effect in women. Decreases in alcohol intake only had an effect in men, with decreases in HDL-cholesterol and systolic blood pressure (P < 0.05), whereas decreasing cigarette smoking in men was associated with significant increases in insulin, glucose, triglycerides, waist and BMI (P < 0.001), and in women HDL-cholesterol, waist circumference and BMI increased (P < 0.02). These results were mainly caused by those who had stopped smoking. CONCLUSIONS: Increases in physical activity over the 3-year period were associated with beneficial effects on syndrome parameters, particularly in men. Smoking cessation and alcohol moderation produced mixed effects on these parameters.     

Leptin and other components of the Metabolic Syndrome in Mauritius--a factor analysis

OBJECTIVE: To use factor analysis to examine the putative role of leptin in the Metabolic Syndrome, and to define better the associations among observed variables and the identified factors. DESIGN: Factor analysis of cross-sectional data from a 1987 survey. SUBJECTS: Non-diabetic residents of Mauritius who participated in population-based surveys in 1987 and 1992 (1414 men and 1654 women). MEASUREMENTS: Fasting and 2 h plasma glucose and insulin following a 75 g oral glucose load; seated blood pressure; body mass index (BMI); waist-to-hip ratio (WHR); and fasting serum triglycerides, HDL-cholesterol, leptin and uric acid concentrations. RESULTS: Principal components factor analysis revealed three factors for men and women that explained between 54 and 55% of the observed variance of the 12 measured variables. General features of these factors were as follows: factor 1, WHR, BMI, leptin, fasting and 2 h insulin, triglycerides, and HDL-cholesterol; factor 2, systolic and diastolic blood pressure, uric acid (men only), and fasting glucose (women only); and factor 3, fasting and 2 h glucose and insulin. Only three variables loaded on more than one factor with a loading > or = 0.4 (fasting and 2 h insulin, fasting glucose in women only). Leptin loaded on one factor only in both men and women. CONCLUSIONS: Since multiple factors underlie the Metabolic Syndrome, and since no observed variable loads on all three factors, more than one mechanism might account for the observed clustering of risk characteristics. Leptin does not unite features of this syndrome due to its loading on one factor only. Uric acid is related to a different factor in men and women. The absence of gender differences in factor loadings argues for similar mechanisms for the Metabolic Syndrome in men and women in Mauritius. International Journal of Obesity (2001) 25, 126-131     

Oxidative stress in the metabolic syndrome

The metabolic syndrome represents a cluster of several risk factors for atherosclerosis that increases the risk of future cardiovascular events. In this study, we evaluated whether oxidative stress is increased in subjects with the metabolic syndrome. We studied 100 subjects (50 men and 50 women) with the metabolic syndrome, as defined by the Adult Treatment Panel III, and 50 (25 men and 25 women) matched subjects without the syndrome. Insulin sensitivity was assessed with the homeostasis model assessment (HOMA) methods; endothelium-dependent flow-mediated vasodilation (FMD) was evaluated in the right brachial artery with a high-resolution ultrasound machine; oxidative stress was assessed by measuring the circulating levels of nitrotyrosine (NT), considered a good marker for the formation of endogenous peroxynitrite. Compared with control subjects, patients with the metabolic syndrome had greater waist circumference, higher HOMA and systolic pressure values, higher triglyceride and lower HDL-cholesterol levels. NT levels were higher (0.44+/-0.12 micromol/l, mean+/-SD) while FMD was lower [7.3 (4.4/9.6), median and interquartile range] in subjects with the metabolic syndrome as compared with control subjects [0.27+/-0.08 and 11.8 (8.6/14.9), respectively, p<0.001]. There was an increase in NT levels and HOMA score as the number of components of the metabolic syndrome increased. NT levels were associated with waist circumference (r=0.38, p=0.01), triglycerides (r=0.32, p<0.02), systolic blood pressure (r=0.21, p<0.05) and fasting glucose (r=0.24, p<0.05). The oxidative stress that accompanies the metabolic syndrome is associated with both insulin resistance and endothelial dysfunction, providing a connection which is highly deleterious for vascular functions.     

Genetic versus environmental aetiology of the metabolic syndrome among male and female twins

Aims/hypothesis. The aetiology of the metabolic syndrome including hyperinsulinaemia, glucose intolerance, dyslipidaemia, hypertension and obesity is not known. We studied the relative impact of genetic versus environmental factors for the development of the components in the syndrome among male and female twins. Methods. A total of 303 elderly twin pairs participated in the study. We report concordances and heritability estimates of the components by classic twin analysis to assess the proportion of variation attributed to genetic factors. Results. All components correlated significantly. The concordance rates for glucose intolerance, overall obesity and low HDL-cholesterol were significantly higher among monozygotic than dizygotic twins indicating a genetic influence on the development of these phenotypes. The heritability estimates for glucose concentration, BMI and HDL-cholesterol among monozygotic twins confirmed these findings. The heritability estimates for waist-to-hip ratio, fasting insulin and triglycerides, however, were low, indicating a major environmental influence. We found a higher genetic influence on glucose intolerance and systolic blood pressure and a lower genetic influence on low HDL-cholesterol and diastolic blood pressure among male twins compared to female twins. Conclusion/interpretation. Based on the correlations between the components in the syndrome, we propose a core complex including hyperinsulinaemia, obesity, hypertriglyceridaemia and low HDL-cholesterol with only weak associations to glucose concentrations and blood pressure levels. The study confirms the notion of a multifactorial aetiology of the components including genetic and non-genetic factors. The differences in aetiology between male and female twins indicate an influence of sex on several of the components in the metabolic syndrome. [Diabetologia (2001) 44: 537–543] Received: 2 October 2000 and in revised form: 2 January 2001     

Microalbuminuria is associated with the insulin resistance syndrome independent of hypertension and type 2 diabetes in the Korean population

To investigate whether microalbuminuria is associated with the insulin resistance syndrome independent of hypertension and type 2 diabetes, we studied the association between microalbuminuria and features of insulin resistance syndrome in Korean general population. We selected 1006 subjects by a random cluster sampling among residents aged >40 years living in the Chung-Up district, a rural area of South Korea. Subjects were stratified by oral glucose tolerance status [normal glucose tolerance (NGT), impaired glucose tolerance (IGT), and diabetes mellitus], and by the presence or absence of hypertension. Urinary albumin excretion rate (UAER) was determined using timed overnight urine collection. Various cardiovascular risk factors including anthropometric indices, serum lipid, true insulin and proinsulin concentrations were also measured. The prevalence of microalbuminuria (UAER between 20 and 200 microg/min) increased as the glucose tolerance worsened (6.0% in NGT, 11.8% in IGT, and 21.8% in diabetes; chi(2) trend=25.9, P<0.001). Subjects with microalbuminuria had a higher body mass index (BMI), waist-to-hip circumference ratio (WHR), systolic and diastolic blood pressure (BP), fasting and 2 h plasma glucose, fasting plasma insulin and proinsulin levels, and lower HDL-cholesterol level than subjects without microalbuminuria. In multiple regression analysis, BMI, diastolic BP, 2 h plasma glucose, and fasting plasma insulin levels were found to be independent factors associated with UAER. Multiple logistic regression analysis showed that not only diabetes mellitus and hypertension, but also fasting hyperinsulinemia and waist-to-hip ratio were independent factors associated with the presence of microalbuminuria. When the normotensive, non-diabetic subjects were analyzed separately, fasting hyperinsulinemia and impaired glucose tolerance remained independent variables associated with the presence of microalbuminuria. These results show that microalbuminuria in the Korean general population is associated with hyperinsulinemia and central obesity, and suggest that microalbuminuria is a feature of the insulin resistance syndrome independent of hypertension or type 2 diabetes.     

Body fat and C-reactive protein levels in healthy non-obese men

BACKGROUND AND AIM: The relationships between C-reactive protein (CRP) levels, adipose tissue and metabolic alterations have not been clearly established in healthy non-obese subjects. We investigated the relationships between body fat, CRP levels and metabolic variables in healthy, non-obese sons of patients affected by metabolic syndrome (MS). METHODS AND RESULTS: Age, CRP and interleukin 6 (IL-6) levels, anthropometric measures (body mass index, BMI; waist circumference and waist-to-hip ratio, WHR), total and regional fat content (as determined by means of dual X-ray absorptiometry, DXA), total and LDL cholesterol, and the metabolic variables related to MS (HDL-cholesterol, triglyceride, glucose and insulin levels; the fasting insulin resistance index, FIRI; blood pressure) were evaluated in 85 healthy non-obese sons of MS patients. Linear and multiple regression analyses were used to evaluate the relationships between body fat, metabolic variables and CRP levels, and to investigate whether the association between body fat content and metabolic variables persists after adjustment for CRP levels. Body fat was associated with all of the investigated variables. CRP levels were associated with total and regional body fat, the anthropometric index of weight, age, and with some metabolic alterations (HDL-cholesterol and triglyceride levels, systolic blood pressure, and fasting insulin and LDL-cholesterol levels). The associations between total body fat and the metabolic variables did not change after adjustment for CRP levels. Total body fat was the best predictor of CRP levels (p<0.0001). CONCLUSIONS: In healthy, non-obese sons of MS patients, total body fat is the best predictor of CRP levels, and remains closely associated with metabolic abnormalities after adjustment for CRP levels. These findings strongly support the hypothesis that body fat is the main determinant of metabolic abnormalities and a low inflammatory state, at least in healthy subjects.     

Effect of aging on the relationship between multiple risk factors and waist circumference

OBJECTIVE: To examine the relationship between various coronary risk factors and the different levels of fat distribution in younger (<65 years) and older (> or = 65 years) men and women, using the classifications proposed by the National Heart, Lung and Blood Institute (NHLBI) and the World Health Organization (WHO). DESIGN: Cross-sectional study of subjects enrolled in the Baltimore Longitudinal Study of Aging. MEASUREMENTS: Systolic blood pressure, diastolic blood pressure, fasting glucose, 2-hour glucose, fasting insulin, homeostasis model assessment insulin resistance (HOMAIR), triglyceride, total cholesterol, high-density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol were measured as risk factors. The proportion of subjects with abnormal risk factor levels by waist circumference classifications was determined in the age and gender subgroups. RESULTS: There were significant adverse effects of age per se on all risk factors with the exception of fasting insulin and HOMAIR in both men and women, total cholesterol in men, and diastolic blood pressure in women. HDL-cholesterol was higher in older subjects. There were significant correlations between waist circumference and all of the risk factors in the younger group. Waist circumference did not have a significant correlation with total cholesterol in older men, or with total cholesterol and LDL-cholesterol in older women. The proportion of subjects with an abnormal risk factor level increased with increasing waist circumference for most risk factors in both younger and older subjects, but proportions of subjects in each individual waist group were higher in older than in younger groups for systolic blood pressure, diastolic blood pressure, fasting glucose, and 2-hour glucose in men, and for systolic blood pressure, fasting glucose, 2-hour glucose, total and LDL-cholesterol, and triglyceride in women. CONCLUSIONS: Our data indicate that the waist circumference cutpoints proposed by NHLBI and WHO standards are useful for the prediction of cardiovascular disease risk factors in older as well as in younger men and women.