Prevalence of metabolic syndrome in the general Japanese population in 2000

The metabolic syndrome in East Asians

The metabolic syndrome is an emerging epidemic in developing nations, including East Asian countries such as China, Japan, and Korea. Studies examining the metabolic syndrome have used different definitions, with prevalence often highly dependent on the cut points for abdominal obesity utilized, which have been recommended by the International Diabetes Federation to be lower than standards used in Caucasians and other ethnic groups. Prevalence rates have generally varied from 8% to 13% in men and 2% to 18% in women, depending on ethnic group and definition used, and are consistently lower than most Western Caucasian populations. While recent dramatic changes in lifestyle from Westernization of dietary habits and reduced physical activity present challenges, an emphasis on healthful lifestyle changes remains the cornerstone for metabolic syndrome management. In addition, clinical management focusing on control of obesity, elevated blood pressure, dyslipidemia, and hyperglycemia, with consideration of pharmacologic therapy issues unique to certain Asian populations, remains important for reducing associated cardiometabolic risks.

Eating fast leads to insulin resistance: findings in middle-aged Japanese men and women

OBJECTIVE

To examine relationships between speed of eating and insulin resistance.

METHODS

Cross-sectional study of 2704 male (mean age and BMI: 48.2 y and 23.3 kg/m(2)) and 761 female (46.3 y and 21.8 kg/m(2)) non-diabetic Japanese civil servants, 75% clerical, and 25% manual laborers, using a two-part questionnaire on life-style factors and diet history with self-assessment of categorical speed of eating and energy intake over a 1-month period. We measured BMI, blood glucose and insulin concentrations and calculated insulin resistance using the homeostasis model assessment of insulin resistance: (HOMA-IR).

RESULTS

BMI correlated with eating rate in both sexes, and with daily energy intake in men. Multiple regression analysis of log HOMA-IR by categorical speed of eating, adjusting for age, energy intake and lifestyle factors showed a statistically significant gradual increase in HOMA-IR with increases in relative eating rate in men (p<0.001, for trend) and in women (p<0.01). Adjusting for BMI, this positive relationship appeared only in men (p=0.03).

CONCLUSIONS

Our results suggest that eating fast is independently associated with insulin resistance in middle-aged Japanese men and women.

Metabolic syndrome mortality in a population-based cohort study: Jichi Medical School (JMS) Cohort Study

BACKGROUND

Metabolic syndrome is known to increase morbidity and mortality of cardiovascular disease. The National Cholesterol Education Program Adult Treatment Expert Panel III in 2001 (revised in 2005) and the Japanese definition of metabolic syndrome were launched in 2005. No study regarding the association between metabolic syndrome by Japanese definition and mortality has been performed. The aim of this study was to clarify the prevalence of metabolic syndrome and its effects to mortality in a population-based cohort study.

METHODS

A total of 2176 subjects who satisfied the necessary criteria for metabolic syndrome were examined between 1992 and 1995 as a part of Jichi Medical School Cohort Study by Japanese definition. Cox's proportional hazard models were used to analyze the association of metabolic syndrome with mortality.

RESULTS

The prevalence of metabolic syndrome was 9.0% in males and 1.7% in females. There were 17 deaths (14 males), including 6 cardiovascular deaths (5 males), during a 12.5-year follow-up period among metabolic syndrome subjects. After adjusting for age, smoking status, and alcohol drinking status, the hazard ratio (95% confidence interval) for all-cause mortality was 1.13 (0.64-1.98) in males and 1.31 (0.41-4.18) in females, and HR for cardiovascular mortality was 1.84 (0.68-4.96) in males, and 1.31 (0.17-9.96) in females.

CONCLUSION

No statistical significant relationship between metabolic syndrome by Japanese definition and all-cause mortality was observed in a population-based cohort study.

Metabolic syndrome pandemic

The metabolic syndrome is a multiplex risk factor that consists of several risk correlates of metabolic origin. In addition, to dyslipidemia, hypertension, and hyperglycermia, the syndrome carries a prothrombotic state and a proinflammatory state. Persons with the metabolic syndrome are at essentially twice the risk for cardiovascular disease compared with those without the syndrome. It further raises the risk for type 2 diabetes by about 5-fold. Although some investigators favor keeping risk factors separate for purposes of clinical management, others believe that identifying individuals with an aggregation of risk factors provides additional useful information to guide clinical management. In particular it focuses attention on obesity and sedentary life habits that are the root of the syndrome. This review addresses the prevalence of this clustering phenomenon throughout the world. Such seems appropriate because of the increasing prevalence of obesity in almost all countries. The available evidence indicates that in most countries between 20% and 30% of the adult population can be characterized as having the metabolic syndrome. In some populations or segments of the population, the prevalence is even higher. On the other hand, in parts of developing world in which young adults predominate, the prevalence is lower; but with increasing affluence and aging of the population, the prevalence undoubtedly with rise.

Appropriate waist circumference cutoff values for persons with multiple cardiovascular risk factors in Japan: a large cross-sectional study

BACKGROUND

In Japan, the current standard waist circumference cutoff value for persons with multiple cardiovascular risk factors remains controversial. In this study we aimed to analyze the health-check examination data from a large Japanese population and propose a revised waist circumference cutoff value.

METHODS

Subjects of this study were 12,725 adults who underwent a health-check by thorough medical examination between April 2006 and March 2007. Medical examinations included measurement of waist circumference, fasting blood triglycerides, HDL cholesterol, glucose concentrations, blood pressure and collection of demographic characteristics. Receiver operating characteristic (ROC) curve analysis was utilized to find appropriate waist circumference cutoff values in relation to multiple cardiovascular risk factors with two or more of the following: dyslipidemia (hypertriglyceridemia or low HDL cholesterol), hypertension, and hyperglycemia defined by the Japanese criteria of metabolic syndrome.

RESULTS

The average age of the subjects was 50.7 years (standard deviation [SD]: 8.8) for men and 49.7 years (SD: 8.6) for women. ROC curve analysis showed maximum sensitivity plus specificity at a waist circumference of 87 cm in men (0.66 and 0.62, respectively) and 83 cm in women (0.73 and 0.70). When analyzed by ten-year age groups, the ROC curves for younger age groups were shifted up and to the left compared to older age groups, but associations between cutoff values and age were not clear.

CONCLUSION

In Japan, the appropriate cutoff value of waist circumference for persons with multiple cardiovascular risk factors is 87 cm for men and 83 cm for women.

Is metabolic syndrome a condition independent of prediabetes and type 2 diabetes mellitus? A report from Turkey

It has been suggested that metabolic syndrome (MetS) overlaps prediabetes and type 2 diabetes and that it is not necessary to consider it as a separate clinical entity. In the present study, patients with normoglycemia and dysglycemia were compared in terms of MetS frequency and MetS criteria characteristics, in order to test the appropriateness of considering MetS as a condition independent of prediabetes and type 2 diabetes. A total of 1222 (801 females, 401 males, mean age: 51.50 11.73 y) consecutive patients attending Internal Medicine outpatient clinics were included. Cases were assigned into two groups: patients with normoglycemia (fasting plasma glucose <100 mg/dl, n = 555) or dysglycemia (fasting plasma glucose >/=100 mg/dl and/or receiving antidiabetic treatment, n = 667). Groups were compared in terms of MetS frequency and MetS criteria characteristics. A 2-hour oral glucose tolerance test was administered to the normoglycemia group. In addition, patients with MetS were assigned into two groups: patients with normoglycemia and dysglycemia. These two groups were also compared in terms of MetS criteria characteristics. Adult Treatment Panel III criteria were used for the diagnosis of MetS. The overall frequency of MetS was 52.2%. MetS was found in 72.7% of patients with dysglycemia and 27.6% of patients with normoglycemia (p = 0.001). Mean systolic and diastolic blood pressure, waist circumference and triglyceride levels were similar between normoglycemic and dysglycemic MetS patients (p>0.05). Impaired glucose tolerance was higher among normoglycemic MetS patients compared to normoglycemic patients without MetS (13.7% vs. 6.5%, p = 0.006). In conclusion, although MetS is a well known risk factor for type 2 diabetes, our results support that it is a separate entity independent of prediabetes and type 2 diabetes mellitus.

Relationship between A-3826G polymorphism in the promoter of the uncoupling protein-1 gene and high-density lipoprotein cholesterol in Japanese individuals: a cross-sectional study

BACKGROUND

A-3826G polymorphism within the promoter region of the uncoupling protein-1 (UCP-1) gene is possibly involved in the pathophysiology of obesity and metabolic disorders. However, the effects of UCP-1 A-3826G polymorphism on high-density lipoprotein cholesterol (HDL-C), a major contributor to atherosclerotic disease, still have not been established.

METHODS

A total of 298 healthy Japanese subjects (144 males and 154 females, mean age: 45.2 years) with a body mass index (BMI) of 20.0-30.0 kg/m(2), regular lifestyles, and receiving no medication were enrolled in the cross-sectional study to estimate the relationship of serum HDL-C levels with UCP-1 A-3826G polymorphism by genomic PCR and Bcl1-restriction fragment length polymorphism analysis. We used 1.04 mmol/L of HDL-C in Japanese males and 1.29 mmol/L in Japanese females as cut-off values of low HDL-cholesterolemia.

RESULTS

The genotype and allele frequencies of UCP-1 A-3826G polymorphism were similar to those previously reported in the Japanese population. In males, HDL-C levels of the GG genotype (1.75+/-0.49 mmol/L) were significantly higher than those found in the AA genotype (1.45+/-0.34 mmol/L, p=0.015). In females, the occurrence rate of low HDL-cholesterolemia was significantly different by genotype: a low prevalence in the GG genotype (15.4% in the AA, 4.8% in the AG, 15.4% in the GG genotype, p=0.022). Logistic regression analysis was used to identify risk factors for low HDL-cholesterolemia, with adjustments for age, gender, smoking, alcohol intake, BMI, hypertriglyceridemia, and genotype. The GG genotype was detected as being a significant associated factor (odds ratio =0.11 [95% confidence interval =0.01-0.90], p=0.01), in addition to BMI and the presence of hypertriglyceridemia.

CONCLUSIONS

These results suggest that the GG genotype may be an independent protective factor associated with low HDL-cholesterolemia in this population, although the role of the UCP-1 A-3826G polymorphism in HDL-C is complex and remains controversial. This hypothesis needs further investigation.

Small dense low-density lipoprotein cholesterol is a useful marker of metabolic syndrome in patients with coronary artery disease

AIM

An evaluation of the relation between small dense low-density lipoprotein cholesterol (sd-LDL-C) levels measured by the heparin-magnesium precipitation method and metabolic syndrome (MetS).

METHODS

We have prospectively measured sd-LDL-C levels by the heparin-magnesium precipitation method in 112 Japanese patients (male/female=80/32) with coronary artery disease (CAD) who received percutaneous coronary intervention (PCI). Patients were diagnosed with MetS according to modified Japanese criteria.

RESULTS

A total of 36 patients (32%) met the criteria for MetS. Sd-LDL-C levels were significantly higher in the MetS group than non-MetS group (20.7 +/- 1.5 mg/dL vs. 17.1 +/- 1.0 mg/dL, p=0.042), especially among patients without lipid-lowering therapy (26.4 +/- 2.6 mg/dL vs. 17.5 +/- 1.5 mg/dL, p= 0.0034). Sd-LDL-C levels gradually increased with the number of components used to define MetS (0; 14.5 +/- 1.8 mg/dL, 1; 16.5 +/- 1.8 mg/dL, 2; 16.7 +/- 1.3 mg/dL, 3; 19.3 +/- 1.7 mg/dL, 4; 23.1 +/- 2.1 mg/dL, 5; 40.0 mg/dL, p=0.0071). High-sensitivity C-reactive protein (hs-CRP) levels were significantly higher in the patients with MetS (1.09 +/- 0.17 mg/L vs. 0.67 +/- 0.09 mg/L, p=0.0204).

CONCLUSION

The sd-LDL-C level measured by the heparin-magnesium precipitation method is a useful marker of MetS in Japanese patients with CAD.

Anesthetic management of laparoscopic adjustable gastric banding in Japanese patients with morbid obesity

Laparoscopic adjustable gastric banding (LAGB) is a common type of bariatric surgery worldwide, though not so in Japan. Here we report the anesthetic management of LAGB in ten Japanese patients with morbid obesity. General anesthesia was induced with propofol, fentanyl, and vecuronium bromide and maintained with sevoflurane in oxygen and air (or nitrous oxide in some cases). In a limited number of patients, perioperative epidural analgesia was performed, with fentanyl injected intravenously for analgesia in the remaining patients. Although some special considerations were needed, in perioperative management, including thromboprophylaxis, there were no severe complications in any of the patients.

Prevalence of metabolic syndrome in young men in Japan

AIM

The prevalence of metabolic syndrome, as defined by the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (ATPIII) modified for age (>or=3 of the following abnormalities): waist circumference of at least 80 cm; serum glucose level of at least 110 mg/dL; triglyceride level of at least 110 mg/dL; high density lipoprotein (HDL) cholesterol level of 40 mg/dL or less; and blood pressure (BP) of at least 130/75 mmHg, was estimated in male high school students who attended an annual school health examination.

METHODS

The subjects were divided into three body mass index (BMI) categories (obese: >or=25; mildly obese: 23-24.9: and normal weight: <23 kg/m2). Of the 1446 students (mean age 15 years), 96 (6.6%) were obese and 158 (10.9%) were mildly obese.

RESULTS

The overall prevalence of metabolic syndrome was 1.4%, being present in; 15.6% of obese subjects. Overall, elevated systolic BP was most common (19.9%). In obese subjects, 51% had an elevated systolic BP.

CONCLUSION

Our study suggests that metabolic syndrome is present in more than 1% of male adolescents and 15% of obese male adolescents in Japan.

Is metabolic syndrome a risk factor for carotid atherosclerosis in normotensive and prehypertensive individuals?

AIM

We have investigated whether metabolic syndrome is a risk factor for carotid atherosclerosis also in normotensive or prehypertensive individuals.

METHODS

We analyzed the data from 851 subjects who had a blood pressure of less than 140/90 mmHg and were not taking antihypertensive medication. Metabolic syndrome was defined according to three different criteria: Japan criteria (Japan-MetS); those of the National Cholesterol Education Program (NCEP)-Adult Treatment Panel III (ATP III) (NCEP-MetS); and modified NCEP-ATP III criteria in which body mass index was used as a surrogate for waist circumference (modified NCEP-MetS).

RESULTS

Japan-MetS, NCEP-MetS, and modified NCEP-MetS were found, respectively, in 1%, 4%, and 4%, of women, and in 10%, 5%, and 9%, of men. After the adjustment for gender and age, the association between MetS and carotid atherosclerosis did not reach statistical significance.

CONCLUSION

Although the number of enrolled subjects was relatively small, these data may further support the importance of controlling blood pressure within the optimal range for the purpose of preventing atherosclerosis in individuals with metabolic syndrome.

Regular alcohol consumption improves insulin resistance in healthy Japanese men independent of obesity

BACKGROUND

There is a great deal of controversy surrounding the relationship between alcohol consumption and insulin resistance. This association may be further confounded by the presence of obesity. We aimed to clarify whether regular alcohol consumption improves insulin resistance in healthy Japanese men and whether obesity affects this relationship.

METHODS

We examined 1029 men (ages 24 to 87 y) who had undergone medical checkups. They were divided into non-obese (body mass index (BMI) <25 kg/m(2)) or obese subjects (BMI > or =25 kg/m(2)) and further classified into non-regular drinkers (NRD), moderate drinkers (MD; 1-6 days/week), and daily drinkers (DD; 7 days/week). The homeostasis model assessment of insulin resistance (HOMA-IR) and other cardiac risk factors were compared between the groups.

RESULTS

In both non-obese and obese men, alcohol consumption decreased HOMA-IR in a dose-dependent manner, although HOMA-IR was about 2 times greater in obese men compared to non-obese men in any category (p<0.001). Stepwise logistic regression analysis revealed that alcohol consumption was the independent negative risk factor for HOMA-IR [OR, 0.576 (95% C.I. 0.402-0.824), p=0.003] after adjusting for age, BMI, systolic blood pressure, smoking status, LDL-cholesterol, HDL-cholesterol, and liver dysfunction.

CONCLUSIONS

Regular alcohol consumption improves insulin resistance in healthy Japanese men independent of obesity.

Metabolic syndrome: clinical concept and molecular basis

The metabolic syndrome is a cluster of insulin resistance, elevated blood pressure, and atherogenic dyslipidemia and is a common basis of cardiovascular diseases (CVD). Although the precise mechanism remains to be elucidated, a practical definition is needed. A worldwide definition that considers increased waist circumference as an essential component has been settled. Visceral fat locates upstream of the liver. Free fatty acids and glycerol derived from visceral fat reach the liver and stimulate lipoprotein synthesis and gluconeogenesis, respectively. The adipose tissue produces a variety of bioactive substances conceptualized as 'adipocytokines'. Overproduction of plasminogen activator inhibitor-1 and tumor necrosis factor- seems to relate to the thrombotic and inflammatory tendency. On the other hand, adiponectin, which has antiatherogenic and antidiabetic activities, is reduced in subjects with metabolic syndrome. In Japan, the waist circumference criterion based on visceral fat accumulation has been adopted. The concept of this syndrome has been widely publicized, and health promotion programs based on the concept have commenced in various areas of the country. Such 'Adipo-Do-It' movement is an incentive to encourage physical exercise to reduce visceral fat and is a big challenge to prevent life-style-related diseases and CVD.

Carotid atherosclerosis in normal-weight metabolic syndrome

OBJECTIVE

To examine whether or not individuals with a normal body mass index (BMI) (18.5 kg/m(2)-24.9 kg/m(2)), but who also fulfill the criteria for the metabolic syndrome (MetS) class, can be associated with carotid atherosclerosis.

METHODS

The subjects were consecutive in-patients with a normal BMI (18.5 kg/m(2)-24.9 kg/m(2)) in the Medical Department of Seiyo Municipal Nomura Hospital enrolled between September 1996 and February 2006. The subjects were 452 men aged 69+/-15 (mean+/-standard deviation) years and 542 women aged 74+/-13 years. Carotid atherosclerosis was assessed by carotid intima-media thickness (IMT) on B-mode ultrasonography.

RESULTS

Compared with men with BMI 18.5 kg/m(2) to 20.9 kg/m(2), the odds ratios of the MetS were 2.83 (95% confidence interval [CI], 1.69-4.76) for men with BMI 21 kg/m(2) to 22.9 kg/m(2) and 6.13 (95% CI, 3.57-10.5) for men with BMI 23.0 kg/m(2) to 24.9 kg/m(2) after controlling for age, smoking status, high low-density lipoprotein cholesterol, and uric acid. Using the same regression model and BMI categories in women, the odds ratios were 2.52 (95% CI, 1.42-2.83) and 4.38 (95% CI, 2.42-7.92), respectively. Multivariate-adjusted carotid IMT was significantly greater in men with than without MetS, especially in patients with BMI 23.0 kg/m(2) to 24.9 kg/m(2). Although in women, there were no inter-group differences in categories of normal BMI and MetS.

CONCLUSION

Individuals in the upper normal BMI range have a relatively high prevalence and are at increased risk of having metabolic syndrome. Therefore, screening of individuals with normal or slightly elevated BMI is important in preventing atherosclerosis.