Cardiovascular Disease In Asia Research Articles

Erratum to: Prevalence of diabetes and impaired fasting glucose in the Chinese adult population: International Collaborative Study of Cardiovascular Disease in Asia (InterASIA)

Erratum to: Prevalence of diabetes and impaired fasting glucose in the Chinese adult population: International Collaborative Study of Cardiovascular Disease in Asia (InterASIA)

Dietary Intakes of Antioxidant Vitamins and Mortality From Cardiovascular Disease

Only a few reports have dealt with the association of antioxidant vitamin intakes with mortality or morbidity from cardiovascular disease in Asia. We investigated the relation of dietary vitamins A, E, and C intake with mortality from cardiovascular disease for Japanese men and women. The subjects were 23,119 men and 35 611 women aged 40 to 79 years without a history of cardiovascular disease or cancer who responded to the food frequency questionnaire as part of the Japan Collaborative Cohort Study for Cancer Risk (JACC) Study. They were followed up for a median period of 16.5 years. Hazard ratios were calculated per quintile of dietary vitamins A, E, and C intake by using Cox proportional hazard model. During the 859,962 person-year follow-up, there were 2690 deaths (1343 men and 1347 women) from cardiovascular disease, comprising 1227 (607 men and 620 women) from stroke and 557 (311 men and 246 women) from coronary heart disease. The multivariable hazard ratios (95% CI) associated with the highest versus lowest quintiles of vitamin C intake were 0.70 (0.54 to 0.92) for total stroke, 0.63 (0.41 to 0.97) for coronary heart disease, and 0.79 (0.66 to 0.94) for total cardiovascular disease for women, but the inverse associations observed were weak and did not reach statistical significance for men. No significant association was observed between vitamins A or E intake and risk of mortality for either men or women. Vitamin C intake is inversely associated with mortality from cardiovascular disease for Japanese women.

Progress of Ambient Air Pollution and Cardiovascular Disease Research in Asia

Asian countries are with deteriorating air quality accompanying the rapid economic and social development of the past decades, and the potential health impacts of air pollution have been noticed by researchers in the region. We reviewed the scientific literature on air pollution and cardiovascular diseases (CVD) published by Asian researchers in English since the 1980s to determine whether the findings in Europe and North America can be extrapolated to Asia. Epidemiological studies show that short-term particulate matter pollution is a strong predictor for CVD morbidity and mortality and suggestive on cerebrovascular morbidity and mortality in newly developed countries in Asia. Multicountry epidemiological studies are needed to fully appreciate the extent of air pollution on CVD in Asia, especially less developed Asian countries. New cohort studies should be initiated to improve our understanding of particulate matter's toxicological pathways, long-term exposure effects, and gene-environment interaction on CVD among the Asian population.

Identification of multiple constituents in the traditional Chinese medicine formula Sheng-Mai San and rat plasma after oral administration by HPLC–DAD–MS/MS

Sheng-Mai San (SMS), a traditional Chinese medicine formula, has been used for the treatment of cardiovascular disease in Asia over long period of time. While its effectiveness has been confirmed by clinical use, its active chemical constituents remain unclear. In this paper, an HPLC–DAD–MS/MS method is described for the efficient and rapid identification of the chemical constituents in SMS extract. MS/MS fragmentation behavior of authentic compounds was proposed for aiding the structural identification of the components. A total of 53 compounds were identified or tentatively characterized by comparing their retention times, UV and MS spectra with those of authentic compounds or literature data. HPLC/UV and MS techniques were employed to screen for the potential bioactive components in rat plasma after oral administration of SMS. Twenty-five compounds including 14 prototype components and 11 metabolites were detected in dosed rat plasma compared with blank rat plasma. This identification and structural elucidation of the chemical constituents in the medicine formula and rat plasma may provide important experimental data for further pharmacological and clinical research.

The novel antidote Bezoar Bovis prevents the cardiotoxicity of Toad (Bufo bufo gargarizans Canto) Venom in mice

Toad Venom, called chansu (CS) in China, is an anti-inflammatory drug used in small doses for the treatment of various types of inflammation in China. Its use is hampered by the cardiotoxicity of bufadienolides derived from Toad Venom. Bezoar Bovis is another frequently used drug in Toad Venom preparations for the treatment of inflammatory or cardiovascular diseases in Asia. We explored whether Bezoar Bovis could protect against CS-induced acute toxicity in mice. Toxicity was assessed by the general features of poisoning, electrocardiography (ECG), and levels of creatine kinase (CK), lactate dehydrogenase (LDH) and calcium ions (Ca(2+)) in cardiac tissues. Toad Venom (90 mg/kg) caused opisthotonus, ventricular arrhythmias, and increases in cardiac levels of Ca(2+), CK and LDH. Pretreatment with Bezoar Bovis (120, 240 and 480 mg/kg) significantly reduced the prevalence of opisthotonus and mortality, and prevented cardiotoxicity in CS-treated mice as evidenced by decreases in the scores of arrhythmias and cardiac levels of CK, LDH and Ca(2+). Furthermore, the bilirubin, and taurine derived from Bezoar Bovis offered marked protection against the arrhythmias induced by CS or bufalin in vivo and in vitro. An anti-inflammatory study showed that Bezoar Bovis did not compromise the anti-inflammatory activity of Toad Venom on concanavalin-A (ConA)-stimulated proliferation of human peripheral blood mononuclear cells. These results suggested that Bezoar Bovis elicited protective and anti-arrhythmic effects against Toad Venom intoxication in mice, and is a novel antidote in combination with Toad Venom therapy.

Chewing substances with or without tobacco and risk of cardiovascular disease in Asia: a meta-analysis

To assess whether people who ever use any form of chewing substance in Asia are at increased risk of cardiovascular disease (CVD). PubMed and ISI Web of Science were searched for relevant studies, with no limitation on language or study year. Studies were included if they provided quantitative estimate of the association between ever use of chewing substance and the occurrence of CVD. Two authors independently implemented inclusion criteria, abstracted study characteristics, and performed meta-analysis. Summary relative risks were estimated on the basis of a random effect model. We used Q statistic and Egger's test to examine heterogeneity across studies and potential publication bias, respectively. Eight eligible studies were included. The relative risk of CVD for ever using chewing substances with or without tobacco was 1.26 (95% confidence interval (CI) 1.12-1.40), which was unchanged when restricted to cohort studies [1.25 (1.08-1.42)] or cohort studies in Taiwan [1.31 (1.12-1.51)]. The summary relative risk for ischemic heart disease was 1.27 (1.02-1.52), and was lowered to 1.26 (0.85-1.67) after exclusion of a cross-sectional study. The overall relative risk for cerebrovascular disease was 1.32 (1.08-1.56). On the basis of the Taiwan data, the summary relative risk of CVD for betel (Areca catechu) chewing was 1.30 (1.17-1.44). Data on dose-response were limited to betel chewing in Taiwan, suggesting a relationship between risk of CVD and cumulative exposure. Two large cohorts in Taiwan reported a greater risk of CVD with betel chewing than with smoking. An association was detected between betel chewing with or without tobacco and the risk of CVD. Betel chewing may impose a greater CVD risk than smoking. More effort is needed in developing betel chewing cessation programmes. The relationship between betel chewing and subgroups of CVD requires further investigation.

Diabetes in China: The challenge now.

Diabetes in China: The challenge now.

Study on the radical scavengers in the traditional Chinese medicine formula Shengmai San by HPLC–DAD coupled with chemiluminescence (CL) and ESI–MS/MS

Shengmai San (SMS) has been used for the treatment of cardiovascular disease in Asia for long-time. It has been reported that SMS can protect against oxidative stress and tune immune response in patients. In this paper, a high performance liquid chromatography–diode array detection–chemiluminescence (HPLC–DAD–CL) method for on-line detection was successfully applied to screen antioxidants in complex SMS extracts. The H 2O 2 scavenging activity of every fraction of SMS extracts was measured to evaluate each contribution to the total anti-oxidative activities of the prescription, followed by structures identification of the main active components by LC/MS/MS. HPLC–DAD–CL method was also applied for comparing the scavenging rates of main active components between the individual herbs and SMS. Interestingly, we found that the scavenging activities of main components detected in the individual herbs were different from those in SMS. The experimental data indicated that drug interactions during decocting process could result in the changes of the antioxidants’ solubility. This study demonstrated that HPLC–DAD–CL on-line assay was a useful technique for rapidly screening and identifying bioactive components from complex multi-herbal prescription.

Emilin1 gene and essential hypertension: a two-stage association study in northern Han Chinese population

BackgroundElastogenesis of elastic extracellular matrix (ECM) which was recognized as a major component of blood vessels has been believed for a long time to play only a passive role in the dynamic vascular changes of typical hypertension. Emilin1 gene participated in the transcription of ECM's formation and was recognized to modulate links TGF-β maturation to blood pressure homeostasis in animal study. Recently relevant advances urge further researches to investigate the role of Emilin1 gene in regulating TGF-β signals involved in elastogenesis and vascular cell defects of essential hypertension (EH).MethodsWe designed a two-stage case-control study and selected three single nucleotide polymorphisms (SNPs), rs3754734, rs2011616 and rs2304682 from the HapMap database, which covered Emilin1 gene. Totally 2,586 subjects were recruited from the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA). In stage 1, all the three SNPs of the Emilin1 gene were genotyped and tested within a subsample including 503 cases and 490 controls, significant SNPs would enter into stage 2 including 814 cases with hypertension and 779 controls and analyze on the basis of testing total 2,586 subjects.ResultsIn stage 1, single locus analyses showed that SNPs rs3754734 and rs2011616 had significant association with EH (P < 0.05). In stage 2, weak association for dominant model were observed by age stratification and odds ratio (ORs) of TG+GG vs. TT of rs3754734 were 0.768 (0.584-1.009), 0.985 (0.735-1.320) and 1.346 (1.003-1.806) in < 50, 50-59 and ≥ 60 years group and ORs of GA+AA vs. GG of rs2011616 were 0.745 (0.568-0.977), 1.013 (0.758-1.353) and 1.437 (1.072-1.926) in < 50, 50-59 and ≥ 60 years group respectively. Accordingly, significant interactions were detected between genotypes of rs3754734 and rs2011616 and age for EH, and ORs were 1.758 (1.180-2.620), P = 0.006 and 1.903 (1.281-2.825), P = 0.001, respectively. Results of haplotypes analysis showed that there weren't any haplotypes associated with EH directly, but the interaction of hap2 (GA) and age-group found to be significant after being adjusted for the covariates, OR was 1.220 (1.031-1.444), P value was 0.020.ConclusionOur findings don't support positive association of Emilin1 gene with EH, but the interaction of age and genotype variation of rs3754734 and rs2011616 might increase the risk to hypertension.

Burden of Cardiovascular Disease in Asia: Big Challenges and Ample Opportunities for Action and Making a Difference

Cardiovascular disease (CVD)1 is the leading cause of death in the world, accounting for 30% of deaths globally. The major cardiovascular diseases include coronary or ischemic heart disease, cerebrovascular disease or stroke, hypertension, heart failure, and rheumatic heart disease. Although the CVD mortality rate has declined in the US and the rest of the developed world, the rate has increased in the developing world, including most Asian countries. The estimated number of deaths due to CVD worldwide was 17.5 million in 2005 and will increase to 20 million in 2015. Further, Asian countries have disproportionately high morbidity and mortality from stroke compared with Western countries. These unique patterns of CVD deserve more attention, because half of the world’s population lives in Asia. The December themed issue of Circulation highlighted reviews and original studies on risk factors, prevalence, awareness, treatment, control, mortality, and secular trends of CVD in Asia with a specific focus on China, India, Japan, and Korea. As pointed out in the editorial comment in that issue of Circulation , the relationship between traditional risk factors and CVD is different in Asia than in Western societies, and there are some unique features about risk factors and metabolic abnormalities for CVD in Asia (1). For example, hypertension plays a more important role in the development of heart disease and stroke in Asia than in Western countries. The prevalence of obesity and overweight in Asia has been increasing as a consequence of economic development in the past two to three decades. The rate of increase for diabetes has been even more substantial. Mean cholesterol levels are lower for adults in most Asian countries than in Western countries, but an increasing trend has been observed. Genetic predisposition and the interaction between genetic and environmental factors also contribute …

S35-2 Cardiovascular Disease in Asia The Present and the Future

S35-2 Cardiovascular Disease in Asia The Present and the Future

Gender-specific association between the kininogen 1 gene variants and essential hypertension in Chinese Han population

Kininogens serve as the precursors of potent vasoactive kinin peptides and also function as cysteine proteinase inhibitors. Given its potential role in blood pressure homeostasis, a tagging single nucleotide polymorphism (SNP) based case-control study was conducted to explore the association between kininogen 1 gene common variants and essential hypertension in Chinese Han population. Four tagging SNPs were selected on the basis of the HapMap database and further genotyped in 2411 patients with essential hypertension and 2348 controls from the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA in China). A significant gender-specific association between the kininogen 1 gene common variants and essential hypertension was observed. In male, but not female participants, rs2304456 CC genotype and rs4686799 TT genotype were significantly related to hypertension [odds ratio (OR) = 2.20, 95% confidence interval (CI): 1.24-3.90, P = 0.007 and OR = 1.31, 95% CI: 1.04-1.66, P = 0.025, respectively]. The haplotypes G-C-C-T and the A-A-T-T were significantly associated with essential hypertension in the male population with adjusted OR 1.43 (P < 0.001) and OR 1.24 (P = 0.001), respectively. The haplotype G-A-C-T was in significant association with essential hypertension (OR = 1.42, P = 0.003) as well as systolic blood pressure (P = 0.005) and diastolic blood pressure (P = 0.015). This is the first association study of the kininogen 1 gene with essential hypertension. Both single-locus and haplotype analyses indicated the kininogen 1 gene was associated with essential hypertension and blood pressure traits in the Chinese male population.

Combined L-/T-Type Calcium Channel Blockers

Opening of the voltage-dependent Ca2+ channels permits influx of Ca2+ across the plasma membrane, triggering diverse physiological processes. These channels are widely distributed in the cardiovascular system, constituting the main route for Ca2+ entry essential for excitation and contraction. Ten unique α1 subunits, grouped in 3 families (CaV1, CaV2, and CaV3), that encode the low-voltage–activated T-type and the high-voltage–activated L-, N-, P/Q- and R-type Ca2+ channels, have been identified.1,2 L-type Ca2+ channels are predominantly expressed in the hearts and peripheral vasculature and serve as the preferred molecular target of the initial Ca2+ channel antagonists in the treatment of hypertension.3 Recently, a growing body of evidence has accumulated depicting important roles of T-type Ca2+ channels in the regulation of cardiovascular function, such as generation of pacemaker potential and regulation of arterial resistance.3,4 T-type Ca2+ channels are found in various cell types, including neurons, cardiomyocytes, vascular smooth muscle cells, and endocrine cells, where they participate in a variety of physiological processes, such as low-threshold Ca2+ spike generation, action potential firing, pacemaking, impulse conduction, maintenance of myogenic tone, cell proliferation, and hormone secretion.1 In addition to their predominant role in the regulation of vascular function, T-type Ca2+ channels are also involved in cardiomyocyte growth and survival.3 T-type Ca2+ channel blockers are capable of interrupting certain pathological hypertrophic signaling pathways, including calcineurin-mediated nuclear factor of activated T cells–3 activation.1 The importance of voltage-dependent Ca2+ channels is demonstrated by the clinical efficacy of Ca2+ channels blockers in certain disease conditions, as well as the widespread distribution and function of these channels.1 Three classes of chemically distinct L-type Ca2+ channel blockers have been widely used clinically depending on their biophysical and conformation-dependent interactions …

Increasing prevalence and low awareness, treatment and control of diabetes mellitus among Chinese adults: The InterASIA study

Aims To estimate the prevalence rates of impaired fasting glucose (IFG) and diabetes mellitus (DM) and to evaluate the awareness, treatment, and control of DM in the Chinese adult population. Methods The International Collaborative Study of Cardiovascular Disease in ASIA (InterASIA), a cross-sectional study, was conducted in 2000–2001. A nationally representative sample of 15,236 Chinese adults between 35 and 74 years old who had fasting plasma glucose measured were used for the present research. Awareness, treatment, and control of DM were defined by subjects self-reporting a DM diagnosis and the use of a prescription medication or nonpharmacological intervention for DM, and had a fasting plasma glucose <126 mg/dl, respectively. Results The prevalence rates of IFG and DM in Chinese adults aged 35–74 years were 7.33 and 5.49%, respectively, with the age-standardized prevalence also 7.33 and 5.49%, respectively. Among patients with DM, 23.66% were aware of their DM, 20.33% were taking prescribed medication or nonpharmacological interventions, and 8.28% had fasting plasma glucose <126 mg/dl. Among diabetics who reported a prior diagnosis of DM, 85.22% were taking prescription medication or nonpharmacological interventions and 35% had fasting plasma glucose <126 mg/dl. Conclusions The prevalence rate of DM among Chinese adults has been increasing in recent years. The rates of awareness, treatment and control of DM are relatively low. Improving the awareness, treatment, and control is urgently needed for the intervention of DM in the Chinese adult population.

A coding polymorphism of the kallikrein 1 gene is associated with essential hypertension: a tagging SNP-based association study in a Chinese Han population

The aim of this study was to investigate the association between common variants in the human tissue kallikrein 1 (KLK1) gene and susceptibility to essential hypertension in Chinese Han. A tagging single nucleotide polymorphism (tSNP) approach was used for a case-control study in 2411 patients with essential hypertension and 2348 controls. All DNA samples and clinical data were collected from the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA). Based on the HapMap data of Han Chinese in Beijing (CHB) population, two non-synonymous polymorphisms, namely rs5517 (Glu162Lys) and rs5516 (Gln121Glu), were selected as tSNPs which could efficiently tag eight SNPs of the KLK1 gene with R larger than 90% for both haplotypes and single locus. Significant differences were found between groups for frequencies of rs5517 A allele (42.48% in cases versus 39.32% in controls, P=0.0019) and AA genotype [adjusted odds ratio (OR)=1.25 for AA versus AG/GG, P=0.0067]. The haplotype composed of the rs5517 A and rs5516 G allele significantly increased the risk of hypertension, with adjusted OR of 1.12 [95% confidence interval (CI), 1.04-1.28, P=0.0377] when compared with the common haplotype G-C. Diplotype analysis also showed a significant association between the diplotype of AG-AC and essential hypertension (OR=1.34, 95% CI, 1.07-1.68, P=0.0096). The present study suggested that rs5517 in the KLK1 gene was significantly associated with essential hypertension in a Chinese Han population.

Metabolic Syndrome and the Risk of Ischemic Heart Disease and Stroke Among Japanese Men and Women

Limited evidence was available on the metabolic syndrome and risk of cardiovascular disease in Asia. The purpose of this study is to examine the association of the metabolic syndrome and risk of ischemic cardiovascular disease in Japanese men and women. We conducted an 18-year prospective study of 9087 Japanese people aged 40 to 69 years (3595 men and 5492 women), initially free of ischemic heart disease or stroke. During follow-up, there were 116 (74 men and 42 women) cases of ischemic heart disease and 256 (144 men and 112 women) ischemic strokes. Metabolic syndrome was defined by the modified criteria of the National Cholesterol Education Program Adult Treatment Panel III (NCEP/ATPIII), with the presence of >/=3 of the following factors: (1) serum triglycerides >/=1.69 mmol/L (150 mg/dL); (2) HDL-cholesterol <1.03 mmol/L (40 mg/dL) for men and <1.29 mmol/L (50 mg/dL) for women; (3) glucose >/=6.11 mmol/L (110 mg/dL) fasting or >/=7.77 mmol/L (140 mg/dL) nonfasting, or on treatment; (4) blood pressure > or =130/85 mm Hg or medication use, and (5) body mass index >/=25.0 kg/m(2). For both sexes, high blood pressure, high triglycerides and low HDL cholesterol were associated with increased risks of ischemic heart disease or stroke after adjustment for cardiovascular risk factors. A dose-response relationship was found between the number of metabolic risk factors and incidence of these cardiovascular end points. The multivariable hazard ratio (95% CI) associated with metabolic syndrome was 2.4 (1.4 to 4.0) in men and 2.3 (1.2 to 4.3) in women for ischemic heart disease, and 2.0 (1.3 to 3.1) and 1.5 (1.0 to 2.3), respectively, for ischemic stroke. The contribution of metabolic syndrome to the risks was independent of serum total cholesterol levels but stronger among smokers. The metabolic syndrome is a major determinant of ischemic cardiovascular disease among middle-aged Japanese men and women, in particular among smokers.

Renalase gene is a novel susceptibility gene for essential hypertension: a two-stage association study in northern Han Chinese population

Renalase, a novel flavin adenine dinucleotide-dependent amine oxidase, is secreted by the kidney, degrades circulating catecholamines, and modulates cardiac function and systemic blood pressure (BP). Its discovery may provide novel insights into the mechanisms of BP regulation and the pathogenesis of essential hypertension (EH). We designed a two-stage case-control study to investigate whether the renalase gene harbored any genetic variants associated with EH in the northern Han Chinese population. From the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA in China), 1,317 hypertensive cases and 1,269 normotensive controls were recruited. These total 2,586 subjects were taken as the main study population in this study. In stage 1, all the eight selected single nucleotide polymorphisms (SNPs) of the renalase gene were genotyped and tested within a subsample (503 cases and 490 controls) of the main study population. By single locus analyses, three SNPs, rs2576178, rs2296545, and rs2114406, showed significant associations with EH (P < 0.05). In stage 2, these three SNPs were genotyped on the remaining individuals and analyzed using all the individuals. After Bonferroni correction for multiple comparisons, the associations of rs2576178 and rs2296545 with EH were still significant in stage 2. The cases had higher frequencies of rs2576178 G allele and rs2296545 C allele than the controls (0.55 versus 0.49, P < 0.0001; 0.61 versus 0.55, P < 0.0001). Particularly, under the codominant model, the adjusted odds ratios for rs2576178 GG genotype and rs2296545 CC genotype were 1.58 (95% CI, 1.25 to 2.00; P = 0.0002) and 1.61 (95% CI, 1.26 to 2.04; P = 0.0002), respectively. We also found risk-associated haplotypes and diplotypes, which further confirmed the significant association between the renalase gene and EH. These findings may provide novel genetic susceptibility markers for EH and lead to a better understanding of EH pathophysiology. In addition, further replications in other populations and functional studies would be warranted.

Cohort profile: the Asia Pacific Cohort Studies Collaboration

Although less well recognized than in the West, cardiovascular disease (CVD) is the leading cause of disease in Asia. This is despite known differences in the distribution of risk factors for CVD in Asia, compared with Europe and North America, such as lower average total cholesterol and body mass index (BMI). The nature of CVD also tends to be different in Asia, where there are more strokes than coronary heart disease (CHD) events, and strokes are more often haemorrhagic than ischaemic, compared with the West. By 1999 the knowledge gap in Asia was a clear impediment to progress in treating and preventing CVD in the continent. Most of the existing studies from Asia were of small size or short duration and, thus, could not provide reliable information as to the way risk factors, well-researched in the West, act upon CVD in Asia. A notable exception was the Eastern Stroke and CHD Collaborative Project, which had studied the effects of diastolic blood pressure and total cholesterol on the risk of stroke and coronary disease in China and Japan. This was the starting point for the Asia Pacific Cohort Studies Collaboration (APCSC), which extended the scope of the Eastern Project in several important ways. APCSC covers a wider geographical area, including studies from Australia and New Zealand (ANZ), which provide a ‘Western’ comparison group, as well as increasing numbers for certain pooled analyses. It uses individual participant, rather than summary, data, which allows for more flexible analyses. Also, it collects data on several risk factors for CVD, not just blood pressure and total cholesterol, and records all deaths, including those due to non-cardiovascular causes. Initial funding was provided by the New Zealand Health Research Council and the Australian National Health and Medical Research Council (NHMRC). Twin Secretariats for APCSC were established at the Clinical Trials Research Unit at the University of Auckland, New Zealand and The George Institute for International Health at the University of Sydney, Australia. In later years, Pfizer Inc. of New York provided two substantial unrestricted educational grants to APCSC. Current funding is a mixture of pharmaceutical industry funding (Pfizer), peer reviewed research council funding (NHMRC; through a programme grant), and university funding (a University of Sydney cancer research award). The Secretariat and database are now solely housed within The George Institute.

Association study of the endothelial nitric oxide synthase gene polymorphisms with essential hypertension in northern Han Chinese

Nitric oxide (NO) synthesized by endothelial nitric oxide synthase (eNOS) plays an important role in both the regulation of endothelial function and the control of blood pressure. Up to now, there has been conflicting data regarding the association between three clinically relevant polymorphisms (T-786C, intron4b/a and G894T) of the eNOS gene and essential hypertension. To examine the contribution of the three eNOS gene polymorphisms to the development of hypertension in the northern Han Chinese, a case-control study including 503 hypertensive cases and 490 age-, gender-, and area-matched controls recruited from the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA) was conducted. Genotyping was performed by polymerase chain reaction (PCR) or PCR-restriction fragment length polymorphism (RFLP). The T-786C and intron4b/a polymorphisms were observed in significant linkage disequilibrium (D' = 0.87, P < 0.001). The minor allele frequencies of these three polymorphisms in healthy controls were much lower than those of Caucasians (9.3% vs 39.6% - 42.0%, 8.9% vs 15.0% - 16.0% and 10.9% vs 34.5% - 34.9% for -786C, intron4a and 894T, respectively). Genotype distributions and allele frequencies of the three polymorphisms did not differ between cases and controls (all P > 0.05). In addition, none of the eight estimated haplotypes significantly increased or decreased the risk of hypertension before or after adjustment for several known risk factors. The study results suggest that the three eNOS gene polymorphisms are unlikely to be major genetic susceptibility factors for essential hypertension in the northern Han Chinese population.

The metabolic syndrome in China

The metabolic syndrome is a cluster of abnormalities including obesity, dyslipidaemia, abnormal blood glucose and raised blood pressure [1]. Reaven drew attention to this syndrome, which he called syndrome X [2]. Its importance is increasingly recognized in recent years because it predicts cardiovascular disease and the development of diabetes [3–6]. The metabolic syndrome is heterogeneous, so no definition is entirely satisfactory. The World Health Organization (WHO) proposed a definition in 1998 [7]. In 2001, the third report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel) (NCEP-ATPIII) defined it in terms of waist circumference, blood pressure and blood biochemistry [8, 9]. In 2005, the International Diabetes Federation (IDF) made abdominal obesity a prerequisite in the definition [10]. The WHO definition is difficult to embrace because glucose tolerance tests and measurement of insulin sensitivity are seldom performed in clinical practice. In the USA, the revised NCEP and the IDF definitions are quite consistent, with 92.9% agreement [11]. In other ethnic populations, such as Asians, the new ethnic-specific waist circumference criteria may slightly increase the prevalence of the metabolic syndrome [12].