Plasma total homocysteine concentration and the risk of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study

Homocysteine level and coronary heart disease incidence: a systematic review and meta-analysis

OBJECTIVE

To determine whether an elevated homocysteine level is an independent risk factor for the development of coronary heart disease (CHD) to aid the US Preventive Services Task Force in its evaluation of novel risk factors for incident CHD.

METHODS

Studies of homocysteine and CHD were identified by searching MEDLINE (1966 through March 2006). We obtained additional articles by reviewing reference lists from prior reviews, original studies, editorials, and Web sites and by consulting experts. We included prospective cohort studies that measured homocysteine and Framingham risk factors and the incidence of CHD in the general adult population without known CHD. Each study was quality rated using criteria developed by the US Preventive Services Task Force. We conducted a meta-analysis using a random-effects model to determine summary estimates of the risk of major CHD associated with each 5-micromol/L increase in homocysteine level. The systematic review and meta-analysis were conducted between January 25, 2005, and September 17, 2007.

RESULTS

We identified 26 articles of good or fair quality. Most studies found elevations of 20% to 50% in CHD risk for each increase of 5 micromol/L in homocysteine level. Meta-analysis yielded a combined risk ratio for coronary events of 1.18 (95% confidence interval, 1.10-1.26) for each increase of 5 micromol/L in homocysteine level. The association between homocysteine and CHD was similar when analyzed by sex, length of follow-up, outcome, study quality, and study design.

CONCLUSION

Each increase of 5 micromol/L in homocysteine level increases the risk of CHD events by approximately 20%, independently of traditional CHD risk factors.

Functional COMT Val158Met polymorphism, risk of acute coronary events and serum homocysteine: the Kuopio ischaemic heart disease risk factor study

Background

The role of circulating levels of total homocysteine tHcy in the development of coronary heart disease (CHD) is still under debate. One reason for conflicting results between previous studies on homocysteine and heart diseases could be consequence of different interactions between homocysteine and genes in different study populations. Many genetic factors play a role in folate-homocysteine metabolism, like functional polymorphism (Val108Met) in the Catechol-O-methyltransferase (COMT) gene.

Methodology and Findings

Our aim was to examine the role of COMT Val158Met polymorphism and interaction of this polymorphism with serum tHcy and folate concentration on the risk of acute coronary and events in middle-aged men from eastern Finland. A population-based prospective cohort of 792 men aged 46–64 years was examined as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. During an average follow-up of 9.3 years, there were 69 acute coronary events in men with no previous history of CHD. When comparing the COMT low activity genotype with the others, we found an age and examination year adjusted hazard rate ratio (HRR) of 1.73 (95% confidence interval (CI), 1.07–2.79), and an age, examination year, serum LDL and HDL cholesterol, and triglyceride concentration, systolic blood pressure and smoking adjusted HRR of 1.77 (95% CI, 1.05–2.77). Although serum tHcy concentration was not statistically significantly associated with acute coronary events (HRR for the highest third versus others 1.52, 95% CI, 0.93–2.49), subjects with both high serum tHcy and the COMT low activity genotype had an additionally increased adjusted risk of HRR 2.94 (95% CI 1.50–5.76) as compared with other men.

Conclusions

This prospective cohort study suggests that the functional COMT Val158Met polymorphism is associated with increased risk of acute coronary events and it may interact with high serum tHcy levels.

Serum homocysteine, folate and risk of stroke: Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study

BACKGROUND

Homocysteine and folate have been suggested to have opposite effects on the risk of stroke, although the results are controversial.

DESIGN AND METHODS

The purpose of this study was to assess the effects of serum total homocysteine (tHcy) and serum folate levels on the risk of stroke in a prospective cohort study. The subjects were 1015 men aged 46-64 years and free of prior stroke, examined in 1991-1993 in the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study.

RESULTS

At baseline the mean serum tHcy concentration was 10.9 micromol/l (SD 3.4). During an average follow-up time of 9.6 years, 49 men experienced a stroke, of which 34 were ischaemic. In Cox proportional hazards models, men in the highest tHcy third had a risk factor-adjusted hazard rate ratio (RR) of 2.77 [95% confidence interval (CI): 1.23-6.24] for any stroke and 2.61 (95% CI: 1.02-6.71) for ischaemic stroke, compared with men in the lowest third. The mean baseline serum folate concentration was 10.4 nmol/l (SD 4.1). Men in the highest third of serum folate (>11.2 nmol/l) had an adjusted RR for any stroke of 0.35 (95% CI: 0.14-0.87) and for ischaemic stroke of 0.40 (95% CI: 0.15-1.09), compared with men in the lowest third.

CONCLUSION

Elevated serum tHcy is associated with increased risk of all strokes and ischaemic strokes in middle-aged eastern Finnish men free of prior stroke. On the other hand, high serum folate concentration may protect against stroke.

Serum Homocysteine and Long-Term Risk of Myocardial Infarction and Sudden Death in Patients with Coronary Heart Disease

We have prospectively evaluated the risk of incident coronary events in association with serum total homocysteine in patients with preexisting chronic coronary heart disease. A nested case-control design was used. Total homocysteine concentration was measured in baseline fasting serum samples from patients with chronic coronary heart disease enrolled in the Bezafibrate Infarction Prevention Study (n = 3,090) who developed coronary events during 6.2 years of follow-up (n = 69). They were matched for age and gender with controls without subsequent cardiovascular events. Elevated homocysteine levels were associated with 2.5 times higher risk of subsequent coronary events and each 5 mumol/l increment was associated with a 25% higher risk.

Homocysteine metabolism, hyperhomocysteinaemia and vascular disease: an overview

Hyperhomocysteinaemia has been regarded as a new modifiable risk factor for atherosclerosis and vascular disease. Homocysteine is a branch-point intermediate of methionine metabolism, which can be further metabolised via two alternative pathways: degraded irreversibly through the transsulphuration pathway or remethylated to methionine by the remethylation pathway. Both pathways are B-vitamin-dependent. Plasma homocysteine concentrations are determined by nongenetic and genetic factors. The metabolism of homocysteine, the role of B vitamins and the contribution of nongenetic and genetic determinants of homocysteine concentrations are reviewed. The mechanisms whereby homocysteine causes endothelial damage and vascular disease are not fully understood. Recently, a link has been postulated between homocysteine, or its intermediates, and an alterated DNA methylation pattern. The involvement of epigenetic mechanisms in the context of homocysteine and atherosclerosis, due to inhibition of transmethylation reactions, is briefly overviewed.

Venous Thromboembolism in the ICU and Reversal of Bleeding on Anticoagulants

Venous thromboembolic disease is a very common complication in the ICU. This article reviews incidence, prevention, and therapy related to venous thromboembolism, including both deep venous thrombosis and pulmonary embolism. Special diagnostic and treatment considerations in the ICU setting are highlighted. The increased use of antithrombotic agents has led to an increased number of patients who experience bleeding complications on anticoagulant therapy. This review also addresses the methods of reversing various anticoagulants.

Homocysteine as a risk factor for CVD mortality in men with other CVD risk factors: the Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study

OBJECTIVE

Based on case-control and prospective studies elevated blood total homocysteine (tHcy) has been suggested to be an independent risk factor for cardiovascular diseases (CVD). The purpose of the study was to explore the joint effect of increased serum tHcy concentration and other risk factors on the risk of CVD mortality in middle-aged men without a history of heart disease or stroke.

DESIGN

A prospective, population-based Kuopio Ischaemic Heart Disease Risk Factor (KIHD) Study.

SETTING

Eastern Finland. Subjects. A total of 802 men aged 46-64 years, examined in 1991-93.

MAIN OUTCOME MEASURES

CVD mortality event.

RESULTS

The mean serum tHcy concentration was 10.8 micromol L(-1) (SD 3.3). During the average follow-up time of 10.8 years 50 men experienced a CVD death. The hazard rate ratio for CVD mortality was 1.80 (95% confidence interval: 1.02-3.19) in men in the highest serum tHcy third versus lower thirds after adjustment for cardiovascular risk factors. Furthermore, elevated serum tHcy concentration appeared to increase the risk of CVD death in men who smoke or who have high circulating concentrations of serum total or LDL cholesterol, apo-B apolipoprotein or plasma fibrinogen.

CONCLUSION

We conclude that homocysteine may increase the risk of CVD mortality in middle-aged men from Eastern Finland, and it may especially increase the risk when present with other risk factors for CVD.

Plasma and aqueous humour levels of homocysteine in exfoliation syndrome

BACKGROUND

Recent studies have suggested that the relationship between elevated plasma homocysteine (Hcy) and increased risk of vascular disease holds also for certain diseases of the eye with vascular aetiology. Elevated plasma Hcy levels have been noted among patients with exfoliation syndrome (XFS). The purpose of this study was to establish whether subjects with XFS have higher plasma and aqueous humour Hcy levels values than non-XFS subjects, particularly in relation to vitamin B status.

METHODS

Using a cross-sectional study design, 36 subjects with XFS and 36 non-XFS subjects with intraocular pressure (IOP) lower than 23 mmHg, matched by age and gender, were first selected. The participant exclusion criteria included parameters known to alter Hcy metabolism. In the XFS group, 11 subjects had a concurrent diagnosis of exfoliative glaucoma (XFG). Fasting plasma and aqueous humour Hcy samples were collected, along with erythrocyte folate (E-Fol) and serum vitamin B6 and B12 samples. The Hcy samples were analysed using a fluorescence polarization immunoassay method.

RESULTS

Plasma Hcy level was significantly higher (P=0.020, after Bonferroni correction for multiple testing) in the XFS group than in the controls. The Hcy concentrations in the aqueous humour did not differ statistically between the two groups. Plasma and aqueous humour Hcy concentrations were not statistically significantly correlated within the groups of exfoliation-positive and -negative subjects. E-Fol, and serum vitamin B6 and B 12 levels did not differ statistically between the XFS group and the control group.

CONCLUSIONS

The finding that subjects with XFS are more prone to elevated plasma Hcy emphasizes exfoliation as a clinical sign and a marker of thromboembolic vasculopathies induced by hyperhomocysteinaemia.

Coffee drinking is dose-dependently related to the risk of acute coronary events in middle-aged men

Heavy coffee consumption has been associated with increased coronary heart disease (CHD) risk although many studies have not observed any relation. We studied the effect of coffee consumption, assessed with a 4-d food record, on the incidence of nonfatal acute myocardial infarction or coronary death in a cohort of 1971 men who were 42 to 60 y old and free of symptomatic CHD at baseline in 1984-1989. During a mean follow-up of 14 y, 269 participants experienced an acute coronary event. After adjustment for age, smoking, exercise ischemia, diabetes, income, and serum insulin concentration, the rate ratios (95% CIs) in daily nondrinkers and light (375 mL or less), moderate (reference level), and heavy (814 mL or more) drinkers were 0.84 (0.41-1.72), 1.22 (0.90-1.64), 1.00, and 1.43 (1.06-1.94). To address time dependence of the effect, the analysis was repeated for 75 CHD events that occurred during the first 5 y; the respective rate ratios were 0.42 (0.06-3.10), 2.00 (1.16-3.44), 1.00, and 2.07 (1.17-3.65). Further adjustment for serum HDL and LDL cholesterol concentration, diastolic blood pressure, maximal oxygen uptake, and waist-hip ratio slightly increased the rate ratio for heavy coffee intake. Neither the brewing method (boiling vs. filtering) nor the serum LDL cholesterol concentration had any impact on the risk estimates for coffee intake. In conclusion, heavy coffee consumption increases the short-term risk of acute myocardial infarction or coronary death, independent of the brewing method or currently recognized risk factors for CHD.

Serum folate and homocysteine and the incidence of acute coronary events: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

Several, but not all, prospective studies have shown that low folate intakes, low circulating folate concentrations, or high plasma total homocysteine (tHcy) concentrations are associated with an increased risk of coronary artery disease (CAD).

OBJECTIVE

We examined the relations of both serum folate and serum tHcy concentrations with acute coronary events in middle-aged men from eastern Finland who had no CAD at baseline.

DESIGN

In a population-based prospective cohort study, 1027 men aged 46-64 y were examined in 1991-1993 as part of the Kuopio Ischaemic Heart Disease Risk Factor Study. During an average follow-up of 7.7 y (7900 person-years of follow-up), 114 acute coronary events were observed in 61 men who had no previous history of CAD (n = 810).

RESULTS

In a Cox model, compared with men whose serum folate concentrations were in the lowest tertile, those whose concentrations were in the highest tertile had a risk factor-adjusted relative risk of acute coronary events of 0.35 (95% CI: 0.17, 0.73; P = 0.005). Serum tHcy concentrations were not significantly associated with the risk of acute coronary events (for the highest tertile compared with the lowest, adjusted relative risk = 1.03; 95% CI: 0.57, 1.87; P = 0.932).

CONCLUSIONS

The results of this prospective cohort study do not support the hypothesis that a high circulating tHcy concentration is a risk factor for acute coronary events in a male population free of prior heart disease. However, they do suggest that moderate-to-high serum folate concentrations are associated with a greatly reduced incidence of acute coronary events.

Homocysteine and cardiovascular disease: biological mechanisms, observational epidemiology, and the need for randomized trials

Basic research indicates that homocysteine causes endothelial dysfunction and damage, accelerates thrombin formation, inhibits native thrombolysis, promotes lipid peroxidation through free radical formation, and induces vascular smooth muscle proliferation and monocyte chemotaxis. Most, but not all, observational epidemiological studies indicate that individuals with higher homocysteine levels have increased risks of cardiovascular disease. The magnitude ranges from approximately 20% in prospective studies to approximately 80% in retrospective case-control studies. In all observational epidemiological studies, however, the amount of uncontrolled and uncontrollable confounding is as large as the postulated small to moderate effect size. Thus, the totality of evidence should include randomized trials of sufficient sample size and duration with clinical end points. Folic acid reduces levels of homocysteine, but at present, despite several plausible biological mechanisms and a large body of observational epidemiological data, it is unclear whether supplementation will reduce risks of cardiovascular disease. It is also unclear whether any benefit of folic acid is attributable to lowering homocysteine levels. The current evidence is necessary, but not sufficient to judge causality. Such judgments await the availability of data from large-scale randomized trials. The availability of such data would permit rational clinical decision-making for individual patients and policy decisions for the health of the general public.

The nested case-control study in cardiology

BACKGROUND

The nested case-control study is an efficient epidemiological design whereby a case-control approach is employed within an established cohort. The large number of recent prospective studies and randomized trials conducted in cardiology provide cohorts within which the nested case-control approach is increasingly used.

METHODS

This paper describes the design of the nested case-control study, and evaluates its role in cardiology by reviewing all such studies indexed in Medline from 1966 to 2000. The example of homocysteine is used to illustrate how discrepancies between results of nested case-control and case-control studies played an important role in the decisions and recommendations of national and international organizations.

RESULTS

Seventy-seven nested case-control studies in cardiology were reviewed. The number of studies per year has been increasing since the first publication in 1987. The majority (96%) of studies evaluated potential risk factors for cardiovascular disease while the remainder evaluated drugs with cardiac adverse effects. In studies of homocysteine and coronary artery disease, nested case-control studies did not confirm the strong association suggested by early case-control studies that may have been influenced by bias (eg, selection, publication, or reverse causality). This led national and international organizations to advise against routine screening.

CONCLUSIONS

The nested case-control study is increasingly used to study causal relationships in cardiology. The large cohorts of cardiac patients created by prospective studies, clinical trials, and administrative databases should be exploited using this methodology to assess potential cardiac risk factors and other causal relationships that cannot be studied in randomized trials.

The effects of tobacco smoke on the homocysteine level--a risk factor of atherosclerosis

Homocysteine may promote atherogenesis and thrombogenesis. There is evidence from case - control and cross-sectional cohort studies that there is a positive association between plasma homocysteine levels and coronary artery disease, cerebrovascular disease and peripheral vascular disease. There is also some evidence that certain life-style factors such as cigarette smoking may affect homocysteine levels. In this work is presented a review of recent opinion about the influence of tobacco smoking on homocysteine levels.

[Hyperhomocysteinemia: an independent risk factor or a simple marker of vascular disease? 2. Epidemiological data]

Elevated plasma total homocysteine (tHcy) is considered as a risk factor for occlusive cardiovascular disease (CVD). This concept is based on the observations of premature vascular disease in patients with homocystinuria and on the association between tHcy and increased risk of CVD in prospective studies. However, some observations have raised questions about tHcy as a risk factor. First, low risk population based prospective studies tend to indicate a weak association or no association between tHcy and CVD. Second, several traditional risk factors for CVD are associated with tHcy and may confound the relation between tHcy and CVD. Third, the C667T transition of the methylenetetrahydrofolate reductase causes a moderate increase in tHcy but no or only minor increased CVD risk. Thus, only placebo-controlled intervention studies with tHcy-lowering B-vitamins and clinical endpoints can provide additional valid arguments for the debate over whether tHcy is a causal CVD risk factor.

Coronary heart disease mortality, plasma homocysteine, and B-vitamins: a prospective study

The results of prospective studies on the relations between the plasma concentration of total homocysteine (tHcy) and B-vitamins, on the one hand, and coronary heart disease (CHD) mortality, on the other hand, are inconclusive and scarce considering the relation with B-vitamins. We prospectively determined these relations in a case-cohort study. The full-cohort existed in approximately 36,000 Dutch adults aged 20-59 years at baseline. The statistical analyses were done with a random sample from the cohort (n=630) complemented with all subjects who died of CHD (n=102) during a mean follow-up of 10.3 years. All subjects reported the absence of cardiovascular diseases (CVDs) at baseline. The plasma concentrations of tHcy, folate, PLP, and vitamin B12 were determined in samples obtained at baseline. Men with a tHcy concentration in the highest tertile (T3) compared with men in the lowest tertile (T1) had a relative risk (RR) of 1.14 for CHD (95% confidence interval (CI): 0.50, 2.61) after adjusting for age, study center, hypertension, HDL and total cholesterol, smoking, and creatinine. For women, this RR was 2.04 (95% CI: 0.48, 8.62). For each 5 micromol/l increase in tHcy, the RR of CHD was 1.03 (95% CI: 0.83-1.29) for men and women combined. In women only, high folate levels were associated with a statistically significant protection of fatal CHD (T3 versus T1; RR: 0.22, 95% CI: 0.06, 0.87). Plasma PLP (B6) and vitamin B12 concentrations were not associated with CHD risk. We conclude that elevated tHcy concentrations do not seem to be a risk factor for CHD mortality in these relatively young healthy Dutch subjects free of baseline CVD. Higher folate concentrations may be protective of CHD, but this needs confirmation.

Folate intake, plasma folate and homocysteine status in a random Finnish population

OBJECTIVE

To assess the folate status of Finnish adults using plasma folate and homocysteine as biomarkers and to evaluate dietary and supplementary folate intakes.

MATERIALS AND METHODS

Plasma folate, vitamin B(12) and total homocysteine (tHcy) were determined in a random sample of 643 subjects aged 25-74 y living in the Helsinki area. The methylenetetrahydrofolate reductase (MTHFR)-genotypes were analyzed from a subsample (n=394). Dietary intake data by 24 h recall and use of vitamin supplements were collected.

RESULTS

Plasma folate was normal (>/=5 nmol/l) in 99% of subjects and optimal (>/=8 nmol/l) in terms of a minimum tHcy in 90%. Mean plasma folate of non-supplement users was 13.7 and 12.9 nmol/l and tHcy 11.3 and 9.2 micro mol/l for men and women, respectively. Elevated tHcy (>14 micro mol/l) was found in 11% of subjects. Homozygote frequency for MTHFR genotype TT was 5.0% and their plasma tHcy was 14.8 micro mol/l compared to the mean of the other subjects, 10.5 micro mol/l, P<0.05. The mean dietary folate intake was 241 micro g/day (29 micro g/MJ of energy) for men and 205 micro g/day (33 micro g/MJ) for women, respectively. The main dietary sources of folate were vegetables 12%, wholemeal ryebread 11%, fruits 10%, and potato 10%. Regular supplement users (n=97) received on average 207 micro g folic acid per day from supplements.

CONCLUSIONS

The folate status of Finnish adults seems to be adequate according to energy adjusted folate intake, plasma folate and homocysteine. The MTHFR homozygote frequency was low compared to other countries. Regular use of supplementary folic acid less than 300 micro g increased plasma folate, but supplemental folic acid over 300 micro g was required to lower tHcy values significantly.

Relation of plasma total homocysteine to cardiovascular mortality in a French population

Although there is considerable epidemiologic evidence for a relation between plasma homocysteine (HCY) and cardiovascular (CV) disease, the role of HCY as a causal CV risk factor remains controversial, mainly because of the intercorrelation between HCY and other CV risk factors. The goal of the present nested case-control prospective study is to determine the multiadjusted relation between HCY and CV mortality in a large and low CV risk population after a mean follow-up of 14 years. In 1980 and 1981, plasma was saved from 5,000 patients who underwent a systematic health checkup, including clinical and biologic examinations. In 1999, HCY concentration was measured in 110 subjects who died of CV disease (cases) and in 154 randomly matched survivors (control subjects). Statistical analysis was adjusted for CV risk factors. Based on Cox analyses, 3 factors emerged as independent predictors of CV mortality: C-reactive protein, systolic blood pressure, and HCY. The adjusted hazard ratio for CV mortality was 1.22 (95% confidence interval 1.04 to 1.41) per 1 SD (3.9 micromol/L) increment of HCY. Thus, HCY is an independent risk predictor for CV mortality. Because of extensive adjustment procedures, the present study provides additional epidemiologic evidence for a causal relation between HCY and CV disease.

The Hordaland Homocysteine Studies

The Hordaland Homocysteine Study is a population-based screening of total plasma homocysteine (tHcy) in approximately 18,000 men and women aged 40-67 yr that took place in 1992-1993 in the county of Hordaland in Western Norway. In this cohort, tHcy was associated with several physiologic and life-style factors, including age and gender, blood pressure, serum cholesterol, smoking, alcohol and coffee consumption, physical activity, diet, and vitamin status. All associations with established cardiovascular risk factors were in the direction expected to confer increased risk. In a subset of 5,883 women aged 40-42 yr, tHcy was associated with previous pregnancy outcomes, including preeclampsia, placental abruption, and neural tube defects. This article reviews the published results from the Hordaland Homocysteine Study in the light of relevant literature. The Hordaland Homocysteine cohort will be used for future investigations of the stability of tHcy and vitamin status over time, and to investigate associations with mortality and morbidity including cancer incidence.

Serum homocysteine, creatinine, and glucose as predictors of the severity and extent of coronary artery disease in asymptomatic members of high-risk families

BACKGROUND

There has been no previous study to determine the severity and extent of coronary artery disease (CAD) in subjects with no diagnosis or symptoms of CAD at the time of the angiography.

METHODS

Fifty-three subjects, who were siblings of patients with early onset CAD, underwent coronary angiography. Indices to describe per-patient characteristics of CAD were calculated, based on computer-aided quantitative coronary angiography. Clinical and laboratory characteristics were correlated to the angiographic parameters.

RESULTS

Serum total homocysteine (rho = 0.29, P < 0.05) and creatinine (rho = 0.47, P = 0.001) levels were related to the global atheroma burden index. The median of the atheroma burden index was two times higher in the top homocysteine quartile compared to the lowest quartile. The overall atheroma burden index correlated significantly with the fasting blood glucose level in all subjects. Diabetes, especially when albuminuria was present, was a powerful risk factor. In a multivariate analysis, only age and sex were independent predictors of atheroma burden.

CONCLUSIONS

Serum homocysteine and creatinine concentrations, and diabetes with albuminuria were found to be markers of the severity and extent of CAD in subjects of high-risk families without symptoms of CAD.

Homocysteine and methylenetetrahydrofolate reductase genotype: association with risk of coronary heart disease and relation to inflammatory, hemostatic, and lipid parameters

AIM

It has been suggested that homocysteine (tHcy) levels and methylenetetrahydrofolate reductase (MTHFR) genotype are primary risk factors for coronary heart disease (CHD). We performed a case-control study to investigate whether tHcy levels and MTHFR genotype (677 C-->T mutation and 1298 A-->C mutation) are associated with CHD under special consideration of the possibility for confounding.

METHODS

German speaking patients aged 40-68 years who underwent coronary angiography at the University of Ulm between April 1996 and November 1997 and who had at least one coronary stenosis greater than 50% were included in the study. Controls were sampled from voluntary blood donors and were matched for sex and age. tHcy levels were measured by high performance liquid chromatography and MTHFR genotype by means of polymerase chain reaction. In addition, C-reactive protein, fibrinogen, plasma viscosity, leukocytes, HDL-cholesterol and Lp(a) were determined.

RESULTS

Overall, 312 patients and 479 controls were enrolled in the study (response in patients 78%, in controls 84%). Mean tHcy value was 9.43 micromol/l in CHD patients and 8.91 micromol/l in controls (P=0.145). Prevalence of 677TT-polymorphism was 9.9% in patients and 10.4% in controls (P=0.295). Prevalence of 1298CC-polymorphism was 9.7% in patients and 13.8% in controls (P=0.346). There was a clear association of tHcy-values, but not of 677TT- or 1298CC-genotype with conventional CHD risk factors. After adjustment for these risk factors no increased risk for CHD could be associated with increased tHcy-values, with 677TT or 1298CC-genotype, or with their combination. Also no statistically significant relationships of these parameters to inflammatory, rheologic or hemostatic parameters or lipids were detectable.

CONCLUSION

These results do not confirm an independent relationship of tHcy values and MTHFR genotype with risk of CHD in the population studied.

Homocysteine and major coronary events: a prospective population study amongst women

OBJECTIVES

To study serum homocysteine concentration for its prediction of major coronary heart disease events amongst women.

DESIGN

A case-control study nested within a follow-up study. Subjects. A total of 74 and 75 major coronary events (coronary deaths or nonfatal myocardial infarction) which occurred in women with and without known heart disease, respectively, during a 13-year follow-up and two individually matched controls per case. Main outcome measure. Major coronary event.

RESULTS

Amongst women with baseline heart disease, the relative risk (95% CI) of such events, adjusted for age, smoking, hypertension, diabetes, serum cholesterol and body mass index, was 3.32 (1.05-10.5) in the highest homocysteine quintile compared with the lowest quintile. Amongst women free of heart disease at baseline, the corresponding relative risk value was 0.77 (0.24-2.45).

CONCLUSIONS

This prospective study support the hypothesis that homocysteine is a risk factor for coronary events in women with heart disease.