Estrogen receptor alpha gene variation is associated with risk of myocardial infarction in more than seven thousand men from five cohorts.

Understanding the mechanisms by which estrogens affect cardiovascular disease risk, including the role of variation in the gene for estrogen receptor alpha (ESR1), may be key to new treatment strategies. We investigated whether the CC genotype at ESR1 c.454-397T>C is associated with increased risk among men. Study of more than 7000 whites in 5 cohorts from 4 countries provided evidence that genotype CC, present in roughly 20% of individuals, is a risk factor for nonfatal acute myocardial infarction (odds ratio=1.44; P<0.0001), after adjustment for established cardiovascular risk factors. After exclusion of younger subjects from 2 cohorts, because of age interaction, the odds ratio increased (to 1.63).

Variation in the UCP2-UCP3 gene cluster predicts the development of type 2 diabetes in healthy middle-aged men.

The impact of the UCP2 -866G>A and UCP3 -55C>T variants on prospective risk of type 2 diabetes was examined over 15 years in 2,936 healthy middle-aged men (mean age 56 years). Conversion to diabetes (n = 169) was associated with higher BMI, blood pressure, cholesterol, triglycerides and C-reactive protein. The hazard ratio (HR) for diabetes of a BMI >30 kg/m(2) was 3.96 (95% CI 2.87-5.47). Homozygosity for the UCP2A or UCP3T alleles accelerated the onset of diabetes, with significant differences in risk of diabetes at 10 years (HR [95% CI] UCP2AA vs. GA+GG 1.94 [1.18-3.19], P = 0.009; UCP3TT vs. CC+ CT 2.06 [1.06-3.99], P = 0.03) but less so at 15 years (UCP2AA 1.42 [0.92-2.19], P = 0.1; UCP3TT 1.57 [0.87-2.04], P = 0.13). Men who were homozygous for both UCP2AA and UCP3TT (1.5% of men) had a risk for diabetes at 10 years of 4.20 (1.70-10.37), P = 0.002. These genotype effects were additive with obesity, and men with a BMI >30 kg/m(2) and this genotype combination had a 10-year risk of diabetes of 19.23 [5.63-63.69], P < 0.0001. Functional promoter variants UCP2 and UCP3 increase the prospective risk of diabetes. Although the mechanism of the UCP2 effect is likely to be caused by increased expression in the pancreas and subsequent reduced insulin secretion, the mechanism of the UCP3 effect is currently unknown. Both effects are exacerbated by obesity.

IL6 gene promoter polymorphisms and type 2 diabetes: joint analysis of individual participants' data from 21 studies.

Several lines of evidence indicate a causal role of the cytokine interleukin (IL)-6 in the development of type 2 diabetes in humans. Two common polymorphisms in the promoter of the IL-6 encoding gene IL6, -174G>C (rs1800795) and -573G>C (rs1800796), have been investigated for association with type 2 diabetes in numerous studies but with results that have been largely equivocal. To clarify the relationship between the two IL6 variants and type 2 diabetes, we analyzed individual data on >20,000 participants from 21 published and unpublished studies. Collected data represent eight different countries, making this the largest association analysis for type 2 diabetes reported to date. The GC and CC genotypes of IL6 -174G>C were associated with a decreased risk of type 2 diabetes (odds ratio 0.91, P = 0.037), corresponding to a risk modification of nearly 9%. No evidence for association was found between IL6 -573G>C and type 2 diabetes. The observed association of the IL6 -174 C-allele with a reduced risk of type 2 diabetes provides further evidence for the hypothesis that immune mediators are causally related to type 2 diabetes; however, because the association is borderline significant, additional data are still needed to confirm this finding.

The solid fat content of stearic acid-rich fats determines their postprandial effects.

BACKGROUND: The process of randomization is used commercially to harden fats as an alternative to partial hydrogenation, but its effects on cardiovascular disease risk factors are uncertain. OBJECTIVE: The objective was to compare the chronic and acute effects of randomization of a fat rich in 1,3-distearyl, 2-oleyl glycerol on fasting and postprandial lipids, glucose, insulin, and activated clotting factor VII (FVIIa) concentrations. DESIGN: A crossover design study in 16 men compared fasting and postprandial lipid, glucose, insulin, and FVIIa concentrations at baseline and after a 3-wk diet providing 30 g unrandomized or randomized shea butter and sunflower oil blends (SSOBs), both of which contained approximately 50% stearic acid. Fecal fat excretion was measured during each dietary period. Postprandial changes were assessed after the consumption of meals providing 50 g test fat. A subsequent study compared postprandial changes after the consumption of an oleic acid-rich sunflower oil meal and an unrandomized SSOB meal. RESULTS: Both SSOBs were well digested and absorbed. Randomization did not affect fasting or postprandial lipid, glucose, insulin, or FVIIa concentrations. Compared with the oleic acid-rich meal, the unrandomized SSOB resulted in 53% lower postprandial lipemia, 23% higher hepatic lipase activity, and a 25% lower postprandial increase in FVIIa concentration. The solid fat contents at 37 degrees C were 22%, 41%, and 0% with the unrandomized SSOB, randomized SSOB, and oleic acid-rich meals, respectively. CONCLUSIONS: Stearic acid-rich triacylglycerol in both unrandomized and randomized forms does not adversely affect lipid risk factors for cardiovascular disease. The high proportion of solid fat at 37 degrees C may explain the decreased postprandial lipemic response.

Is the influence of variation in the ACE gene on the prospective risk of Type 2 diabetes in middle-aged men modified by obesity?

There is strong evidence for the presence of a functional renin-angiotensin system in diabetogenic tissues, and ACE (angiotensin-converting enzyme) inhibitors may improve glucose metabolism in those individuals at high risk of developing T2DM (Type 2 diabetes). In the present study, we tested the hypothesis that subjects with genetically lower plasma and tissue ACE activity, because of their ACE [I/D (insertion/deletion)] genotype, would have a lower risk of T2DM in 2642 healthy middle-aged Caucasian men (mean age, 56 years) followed-up for 15 years. Obesity was the strongest predictor of T2DM, with an HR (95% CI) [hazard ratio (95% confidence interval)] of 3.74 (2.66-5.26) (P<0.0001). Overall there was no association between ACE genotype (II homozygotes, n=623; and D allele carriers, n=2019) and risk of T2DM, and although in lean men there was no genotype difference in risk in D allele carriers compared with II homozygotes [adjusted HR=0.75 (95% CI, 0.46-1.22)], in obese (body mass index >30 kg/m(2)) men the risk of T2DM was higher [adjusted HR=4.26 (95% CI, 1.30-13.93)] with a genotype-obesity interaction of P=0.01. A similar pattern of risk was seen by re-analysis of a previously published case-control study, where D allele carriers had a non-significant 1.30 (0.97-1.74)-fold higher risk of developing T2DM than II homozygotes when non-obese, but a 1.79 (1.17-2.72) (P=0.007)-fold higher risk when obese. Further prospective studies are needed to confirm these findings. The ACE D allele may worsen glucose metabolism, which could raise the prospective T2DM risk in obese men, but not in lean men. In obesity, adipose tissue undergoes inflammatory infiltration and the subsequent higher levels of pro-inflammatory angiotensin II may explain this association.

A common interleukin 18 haplotype is associated with higher body mass index in subjects with diabetes and coronary heart disease.

The pleiotropic proinflammatory cytokine, interleukin 18, plays a role in innate immunity and, based on mouse models, influences obesity. We investigated variation within the IL18 gene and its effect on markers of the metabolic syndrome. A tagging single nucleotide polymorphism set of 5 SNPs for the gene encoding interleukin 18 was selected and genotype was determined in 3 separate studies. In 2775 healthy middle-aged men, 6 common haplotypes were seen, but none was associated with body mass index (BMI). In 439 patients who underwent coronary artery bypass graft surgery, Hap2 (frequency, 22%) was present at a lower frequency than in healthy subjects and was associated with higher mean BMI compared with Hap1 (P = .011). In 483 men with type 2 diabetes mellitus, Hap2 was again associated with a higher haplotypic mean BMI (P = .002). Those homozygous for Hap2 had a BMI of 31.2 (1.3) kg/m(2), mean (SE), compared with 28.3 (1.0) kg/m(2) in those not carrying a copy of Hap2. No single SNP could fully explain the effects seen. Therefore, variation within IL18, previously shown to be associated with lower IL18 levels, is influencing measures of obesity both in men with type 2 diabetes mellitus and those with advanced coronary heart disease.

Common variants in the TCF7L2 gene and predisposition to type 2 diabetes in UK European Whites, Indian Asians and Afro-Caribbean men and women.

Common variants of TCF7L2, encoding a beta-cell-expressed transcription factor, are strongly associated with increased risk of type 2 diabetes (T2D). We examined this association using both prospective and case-control designs. A total of 2,676 healthy European white middle-aged men from the prospective NPHSII (158 developed T2D over 15 years surveillance) were genotyped for two intronic SNPs [rs 7903146 (IVS3C>T) and rs12255372 (IVS4G>T)] which showed strong linkage disequilibrium (D' = 0.88, p<0.001; R(2)=0.76, p<0.001). The IVS5T allele frequency was 0.28 (95% CI 0.27-0.29) and 0.33 (0.28-0.39) in healthy and T2D, respectively (p=0.04). Compared to CC men, CT and TT men had an adjusted [for age, body mass index, systolic blood pressure, triglyceride and C-reactive protein levels] hazard ratio for T2D of 1.65 (1.13-2.41) and 1.87 (0.99-3.53), respectively, p<0.01. The population attributable fraction for diabetes risk was 17%. In 1459, European white T2D men and women (60% male), T allele frequency was 0.36 (0.34-0.38), and compared to NPHSII healthy men the OR for T2D for the CT and TT subjects was 1.43 (1.24-1.65) and 2.11 (1.69-2.63), respectively p=<0.0001. A similar effect was observed in 919 T2D Indian Asians [OR=1.50 (1.14-1.99) and 1.64 (1.03-2.63) p=0.003] and 385 Afro-Caribbean subjects [OR=1.25 (0.90-1.75) and 1.32 (0.74-2.33) p=0.17] compared to non-diabetic ethnically matched subjects from South London. Weaker associations were found for the IVS4G>T in all studies. Linkage disequilibrium between the two SNPs was high in Indian Asians (D'=0.94), but much weaker in Afro-Caribbeans (D'=0.17) and haplotype frequencies differed markedly in this group. These results extend previous observations to other ethnic groups, and strongly confirm that TCF7L2 genotype is a major risk factor for development of T2D.

Effect of interesterification of palmitic acid-rich triacylglycerol on postprandial lipid and factor VII response.

The process of interesterification results in changes in triacylglycerol (TAG) structure and is used to increase the melting point of dietary fats. The acute health effects of this process on palmitic acid-rich fats are uncertain with regard to postprandial lipemia, insulin and factor VII activated (FVIIa) concentrations. Two randomized crossover trials in healthy male subjects compared the effects of meals containing 50 g fat [interesterified palm oil (IPO) versus native palm oil (NPO); n=20, and IPO versus high-oleic sunflower oil (HOS); n=18], on postprandial changes in lipids, glucose, insulin, chylomicron composition and FVIIa. Compared with NPO, IPO decreased postprandial TAG and insulin concentrations. Both NPO and IPO increased FVIIa concentrations postprandially; mean increases at 6 h were 21 and 19%, respectively. Compared with HOS, IPO decreased postprandial TAG (47% lower incremental area under the curve) and reduced the postprandial increase in FVIIa concentration by 64% at 6 h; no significant differences in hepatic and total lipase activities or insulin concentrations were noted. All three test meals increased postprandial leukocyte counts (average 26% at 6 h). The fatty acid composition of the chylomicron TAG was similar to the test fats following all test meals. It is concluded that interesterification of palm oil does not result in adverse changes in postprandial lipids, insulin or FVIIa compared to high oleate and native palm oils.

Effect of varying the ratio of n-6 to n-3 fatty acids by increasing the dietary intake of alpha-linolenic acid, eicosapentaenoic and docosahexaenoic acid, or both on fibrinogen and clotting factors VII and XII in persons aged 45-70 y: the OPTILIP study.

BACKGROUND: Elevated fibrinogen, activated factor XII (FXIIa), and factor VII coagulant activity (FVIIc) are associated with higher risk of fatal ischemic heart disease. This study tested the hypothesis that lowering the dietary ratio of n-6 to n-3 polyunsaturated fatty acids (n-6:n-3) would modify these risk factors in older men and women. OBJECTIVE: The objective of the study was to measure fasting hemostatic risk factors and postprandial changes in activated FVII (FVIIa) concentrations after a 6-mo alteration in dietary n-6:n-3. DESIGN: In a randomized, parallel design in 258 subjects aged 45-70 y, we compared 4 diets providing 6% of energy as polyunsaturated fatty acids at an n-6:n-3 between 5:1 and 3:1 with a control diet that had an n-6:n-3 of 10:1. The diets were enriched in alpha-linolenic acid, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid, or both. RESULTS: Fasting and 3-h plasma triacylglycerol concentrations were 11.1% and 7.2% lower with the diet that had an n-6:n-3 of approximately 3:1 and that was enriched with EPA and DHA than with the other diets. Fasting fibrinogen, FXIIa, FVIIc, FVIIa, and FVII antigen and postprandial FVIIa were not influenced by the diets. Avoiding foods high in fat the day before measurement decreased FVIIc and FVIIa by 8% and 19.2%, respectively. A test meal containing 50 g fat resulted in a mean 47% (95% CI: 42%, 52%) increase in FVIIa 6 h later, but the response did not differ by n-6:n-3. CONCLUSION: Decreasing the n-6:n-3 to approximately 3:1 by increasing the intake of EPA and DHA lowers fasting and postprandial plasma triacylglycerol concentrations in older persons but does not influence hemostatic risk factors.

Effects of altering the ratio of dietary n-6 to n-3 fatty acids on insulin sensitivity, lipoprotein size, and postprandial lipemia in men and postmenopausal women aged 45-70 y: the OPTILIP Study.

BACKGROUND: Insulin resistance is associated with elevated plasma triacylglycerol, low HDL concentrations, elevated postprandial lipemia, and a predominance of small, dense LDLs (sdLDLs). It has been hypothesized that the dietary ratio of n-6 to n-3 (n-6:n-3) polyunsaturated fatty acids (PUFAs) may have favorable effects on these risk factors by increasing insulin sensitivity. OBJECTIVE: The objective was to measure changes in insulin sensitivity, lipoprotein size, and postprandial lipemia after a 6-mo alteration in n-6:n-3. DESIGN: In a randomized, parallel design in 258 subjects aged 45-70 y, we compared 4 diets providing 6% of energy as PUFAs with an n-6:n-3 between 5:1 and 3:1 with a control diet that had an n-6:n-3 of 10:1. The diets were enriched in alpha-linolenic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), or both. Insulin sensitivity was assessed with the homeostatic model assessment of insulin resistance and the revised quantitative insulin sensitivity test. RESULTS: Dietary intervention did not influence insulin sensitivity or postprandial lipase activities. Fasting and postprandial triacylglycerol concentrations were lower, and the proportion of sdLDLs decreased (by 12.7%; 95% CI: -22.9%, 2.4%), with an n-6:n-3 of approximately 3:1, which was achieved by the addition of long-chain n-3 PUFAs (EPA and DHA). CONCLUSIONS: Decreasing the n-6:n-3 does not influence insulin sensitivity or lipase activities in older subjects. The reduction in plasma triacylglycerol after an increased intake of n-3 long-chain PUFAs results in favorable changes in LDL size.

A common variant in the glutathione S transferase gene is associated with elevated markers of inflammation and lipid peroxidation in subjects with diabetes mellitus.

INTRODUCTION: Glutathione S transferases (GST) are enzymes responsible for the metabolism of numerous xenobiotics and play a major cellular antioxidant role. Our aim was firstly, to examine the association between the GST M1/GST mu-1 (GSTM1) and GST T1/GST theta-1 (GSTT1) gene variants with markers of oxidative stress and inflammation in diabetic patients, and secondly to examine the association and potential interaction between these variants and cigarette smoking. METHODS: Seven hundred and seventy-three Caucasian subjects with diabetes and 2592 Caucasian non-diabetic subjects were successfully genotyped. Plasma total antioxidant status, C-reactive protein (CRP), oxidized-LDL (Ox-LDL) and LDL-mean/peak particle diameter were recorded in the diabetes sample. RESULTS: No association was seen between genotype and cardiovascular disease (CVD) risk. In the diabetic subjects, GSTT1-1 compared to GSTT1-0 subjects had significantly higher CRP (p=0.001), Ox-LDL (p=0.004) and smaller LDL particles (p=0.01). In subjects without CVD, there was a significant interaction between the GSTT1-1 variant and smoking in determining Ox-LDL (p=0.04). Furthermore, CVD risk was higher in smokers compared to non-smokers with GSTT1-1. No significant associations were observed by GSTM1. Within the non-diabetic sample, no association was observed between genotype and prospective coronary heart disease (CHD) risk. Of note, the frequency of the GSTT1-1 variant was significantly lower in the diabetes subjects compared to the non-diabetic sample (p=0.01). CONCLUSIONS: This study demonstrates an association between the GSTT1-1 variant and markers of inflammation and lipid peroxidation. Furthermore this variant interacts with smoking to increase lipid peroxidation.

Insight into the nature of the CRP-coronary event association using Mendelian randomization.

BACKGROUND: It is unclear wheather the association between C-reactive protein (CRP) and incident coronary events is free from bias and confounding. Individuals homozygous for a +1444C>T polymorphism in the CRP gene have higher circulating concentrations of CRP. Since the distribution of this polymorphism occurs at random during gamete formation, its association with coronary events should not be biased or confounded. METHODS: We calculated the weighted mean difference in CRP between individuals with variants of the +1444C>T polymorphism in the CRP gene among 4,659 European men from six studies (genotype-intermediate phenotype studies). We used this difference together with data from previous observational studies to compute an expected odds ratio (OR) for non-fatal myocardial infarction (MI) among individuals homozygous for the T allele. We then performed four new genetic association studies (6,201 European men) to obtain a summary OR for the association between the +1444C>T polymorphism and non-fatal MI (genotype-disease studies). RESULTS: CRP was 0.68 mg/l [95% confidence interval (95% CI) 0.31-1.10; P = 0.0001] higher among subjects homozygous for the +1444-T allele, with no confounding by a range of covariates. The expected ORs among TT subjects for non-fatal MI corresponding to this difference in CRP was 1.20 (95% CI 1.07-1.38) using the Reykjavik Heart study data and 1.25 (1.09-1.43) for all observational studies to 2004. The estimate for the observed adjusted-OR for non-fatal MI among TT subjects was 1.01 (95% CI 0.74-1.38), lower than both expected ORs. CONCLUSIONS: A common CRP gene polymorphism is associated with important differences in CRP concentrations, free from confounding. The null association of this variant with coronary events suggests possible residual confounding (or reverse causation) in the CRP-coronary event association in observational studies, though the confidence limits are still compatible with a modest causal effect. Additional studies of genotype (or haplotype) and coronary events would help clarify whether or not the link between CRP and coronary events in observational studies is causal.

Apolipoprotein AIV gene variant S347 is associated with increased risk of coronary heart disease and lower plasma apolipoprotein AIV levels.

The impact of common variants in the apolipoprotein gene cluster (APOC3-A4-A5) on prospective coronary heart disease (CHD) risk was examined in healthy UK men. Of the 2808 men followed over 9 years, 187 had a clinically defined CHD event. Examination of 9 single nucleotide polymorphisms (SNPs) in this group revealed that homozygotes for APOA4 S347 had significantly increased risk of CHD [hazard ratio (HR) of 2.07 (95%CI 1.04 to 4.12)], whereas men homozygous for APOC3 1100T were protected [HR 0.28 (95%CI 0.09 to 0.87)]. In stepwise multiple regression analysis, after entering all the variants and adjusting for established risk factors APOA4 T347S alone remained in the model. Using all nine SNPs, the highest risk-estimate haplotypes carried APOA4 S347 and rare alleles of the two flanking intergenic markers. The protective effect of APOC3 1100T could be explained by negative linkage disequilibrium with these alleles. To determine the association of APOA4 T347S with apoAIV levels, the relationship was examined in 1600 healthy young European men and women. S347 homozygotes had significantly lower apoAIV plasma levels (13.64+/-0.59 mg/dL) compared with carriers of the T347 allele (14.90+/-0.12 mg/dL) (P=0.035). These results demonstrate that genetic variation in and around APOA4, independent of the effects of triglyceride, is associated with risk of CHD and apoAIV levels, supporting an antiatherogenic role for apoAIV.

Oily fish reduces plasma triacylglycerols: a primary prevention study in overweight men and women.

OBJECTIVE: Previous studies have demonstrated benefits of high-dose long-chain omega-3 polyunsaturated fatty acid (LC omega-3 PUFA) supplements on metabolic risk. Effects of increased dietary omega-3 PUFA, via oily fish and/or plant-derived omega-3 PUFAs, are less clear and may be modulated by the omega-6:omega-3 PUFA of the habitual diet. This study examined the effect on cardiovascular disease risk markers of reducing dietary omega-6:omega-3 PUFA by changes in linoleic acid:alpha-linolenic acid (LA:LNA) and/or increasing LC omega-3 PUFA. It tested whether decreases in LA:LNA modulate effects of LC omega-3 PUFA. METHODS: One hundred forty-two subjects, recruited to a 24-wk randomized study, were assigned to a control group or one of four interventions. Intervention groups received two portions of oily fish (4.5 g eicosapentaenoic acid + docosahexanoic acid) or white fish (0.7 g eicosapentaenoic acid + docosahexanoic acid) per week, and replaced habitual household fats with ones high in sunflower (high LA:LNA) or rapeseed (low LA:LNA) oil. RESULTS: Modest dietary manipulations of omega-6 and omega-3 PUFAs resulted in significant group x time interactions for serum triacylglycerols (TAGs; P = 0.05); at 24 wk the control and two oily fish groups showed lower TAG than did the white fish/sunflower group (P = 0.05). Reductions in TAG, associated with increased oily fish intakes, were maximized when combined with lower dietary LA:LNA. There were no significant changes in several other cardiovascular disease risk markers. CONCLUSIONS: Two portions of oily fish per week led to significant reductions in TAG relative to consumption of two portions of white fish per week. Changes in TAG were maximized when combined with lower LA:LNA.

Human paraoxonase gene cluster polymorphisms as predictors of coronary heart disease risk in the prospective Northwick Park Heart Study II.

The anti-atherogenic effect of HDL has been suggested to be partly due to the action of HDL-associated paraoxonase (PON). Three distinct enzymes have been identified, encoded by PON1, PON2 and PON3, clustered on chromosome 7q21-q22. Two cSNPs in PON1 (L55M and Q192R) and one in PON2 (S311C) have been implicated as independent risk factors for coronary heart disease (CHD) in some, but not all, studies. A PON3 SNP (A99A) was identified and the effect of these four PON SNPs on HDL levels and CHD risk was examined in the prospective Northwick Park Heart Study II (NPHSII). Genotype frequencies did not differ between cases and controls but the CHD risk associated with smoking was significantly modified by PON1 L55M genotype. Compared to LL non-smokers, LL smokers had a hazard ratio (HR) of 1.30 (95% CI 0.81-2.06) while M-allele carriers had a HR of 1.76 (1.17-2.67). When genotypes were analysed in combination, men with the genotype PON1 55 LM/MM+PON2 311 CC, had HR of 3.54 (1.81-6.93) compared to PON1 LL+PON2 SS/SC men (interaction P=0.004). These effects were independent of classical risk factors. These data demonstrate the importance of stratifying by environmental factors and the use of multiple SNPs for genetic analysis.

Estrogen receptor alpha gene variation and the risk of stroke.

BACKGROUND AND PURPOSE: Estrogen receptor alpha (ESR1) gene variation is associated with a range of important estrogen-dependent characteristics, including responses of lipid profile and atherosclerotic severity to hormone replacement therapy, coronary heart disease risk, and migraine. The roles that reproductive steroids play in cerebrovascular pathophysiology and ischemia are an important area of investigation. Given that there is a significantly higher risk of myocardial infarction among men with the CC genotype (PP of PvuII) of c.454-397T>C (rs2234693), we asked whether this genotype is associated with a higher risk of stroke. METHODS: Relative risk of stroke by genotype was determined in 2709 participants of the Second Northwick Park Heart Study, white males with a mean baseline age 56 years and follow up 10.5 years. RESULTS: Compared with participants with the ESR1 c.454-397CT or TT genotype, those with the CC genotype had a relative risk of stroke of 1.92 (95% confidence interval, 1.06 to 3.48, P=0.03) after adjustment for age, primary care practice; additional adjustment for body mass index, serum cholesterol and triglyceride levels, hypertension, diabetes, and smoking status. Exclusion of stroke cases with coronary heart disease gave results that were essentially unchanged. CONCLUSIONS: In this study, subjects with the common ESR1 c.454-397CC genotype have a substantial increase in risk of stroke. In another publication, other ESR1 variation was associated with migraine. We thus hypothesize that estrogen receptor variation may provide a basis for the established relationship among estrogens, migraine, and stroke.

Dietary fatty acids and the haemostatic system.

Studies of the effects of dietary fatty acids on the haemostatic system, and their potential relevance for the thrombotic component of coronary heart disease (CHD), have a pedigree as long as those linking dietary fat, plasma lipoprotein metabolism and atheroma. Achievements have not been as impressive, however, partly owing to the relatively slow evolution of our understanding of the complicated physiology, biochemistry and pathology of haemostasis and fibrinolysis, which remains incomplete. Progress was also retarded up to 1980 by a general reluctance to acknowledge the pathogenic importance of thrombosis for myocardial infarction. Interest in dietary fat and the haemostatic mechanism re-emerged with reports of associations of haemostatic variables with plasma triacylglycerol levels and risk of CHD. This review summarises the history, focuses on evidence for dietary C18-unsaturated fatty acids as important determinants of factor VII (FVII) activation and plasminogen activator inhibitor type 1 (PAI-1) levels, and discusses possible underlying mechanisms involving ATP binding cassette (ABC) transporters and peroxisome proliferator-activated receptors. The potential relevance of these effects for CHD is discussed. In the presence of unstable atheromatous plaques, increased levels of activated FVII and PAI-1 induced by diets rich in mixtures of saturated and unsaturated fats may raise the risk of occlusive thrombosis in the event of plaque rupture.

A comparison of the PROCAM and Framingham point-scoring systems for estimation of individual risk of coronary heart disease in the Second Northwick Park Heart Study.

We have compared the predictive value of the PROCAM and Framingham risk algorithms in healthy UK men from the Second Northwick Park Heart Study (NPHS-II) (50-64 years at entry), followed for a median of 10.8 years for coronary heart disease (CHD) events. For PROCAM, the area under the receiver operating characteristic (ROC) curve was 0.63 (95% CI, 0.59-0.67), and not significantly different (p = 0.46) from the Framingham score, 0.62 (0.58-0.66). Sensitivities for a 5% false-positive rate (DR(5)) were 13.8 and 12.4%, respectively. Calibration analysis for PROCAM gave a ratio of observed to expected events of 0.46 (Hosmer-Lemeshow test, p < 0.0001) and 0.47 for Framingham (p < 0.0001). Using measures taken at 5 years of high-density lipoprotein cholesterol and (estimated) low-density lipoprotein cholesterol levels increased the ROC by only 1%. An NPHS-II risk algorithm, developed using a 50% random subset, and including age, triglyceride, total cholesterol, smoking status, and systolic blood pressure at recruitment, gave an ROC of 0.64 (0.58-0.70) with a DR(5) of 10.7% when applied to the second half of the data. Adding family history and diabetes increased the DR(5) to 18.4% (p = 0.28). Adding lipoprotein(a) >26.3 mg/dL (relative risk 1.6, 1.1-2.4) gave a DR(5) of 15.5% (p = 0.55), while adding fibrinogen levels (relative risk for 1S.D. increase = 1.5, 1.1-2.0) had essentially no additional impact (DR(5) = 16.9%, p = 0.95). Thus, the PROCAM algorithm is marginally better as a risk predictor in UK men than the Framingham score, but both significantly overestimate risk in UK men. The algorithm based on NPHS-II data performs similarly to those for PROCAM and Framingham with respect to discrimination, but gave an improved ratio of observed to expected events of 0.80 (p = 0.01), although no score had a high sensitivity. Any novel factors added to these algorithms will need to have a major impact on risk to increase sensitivity above that given by classical risk factors.

Genetic variation in alcohol dehydrogenase 1C and the beneficial effect of alcohol intake on coronary heart disease risk in the Second Northwick Park Heart Study.

Alcohol dehydrogenase 1C (ADH1C or ADH3) genotype reportedly modifies the association between alcohol consumption and coronary heart disease (CHD) risk, as well as influencing plasma high-density lipoprotein (HDL) levels [Hines LM, Stampfer MJ, Ma J, et al. Genetic variation in alcohol dehydrogenase and the beneficial effect of moderate alcohol consumption on myocardial infarction. N Engl J Med 2001;344:549-55]. This relationship has been examined in a sample of middle-aged (50-61 years) men (total of 2773 with 220 CHD events), participating in the prospective Second Northwick Park Heart Study (NPHS II). Alcohol consumption was assessed by questionnaire as the number of units consumed in the previous week. Drinkers experienced lower CHD risk than abstainers [hazard ratio (HR) 0.73 (95% confidence intervals (CI) 0.53, 0.99; p=0.04)] and had significantly higher HDL and apolipoprotein (apo)AI concentrations (both p<0.0001) and a lower fibrinogen (p=0.02). Overall, there was no effect of ADHC1 gamma1>gamma2 genotype on plasma levels of HDL, apoAI or fibrinogen or on CHD risk. To consider whether the effect of alcohol consumption on risk was modulated by genotype, the men were divided into abstainers, modest drinkers (1-3 units/week) and those who consumed more than 3 units/week. Significant alcohol:genotype interaction on CHD risk was observed (p=0.02), with gamma2 homozygotes, who were modest drinkers, displaying 78% CHD risk reduction compared to gamma1 homozygotes (HR=0.22, 95% CI 0.05-0.94). There was, however, no association between genotype and apoAI, HDL or fibrinogen and this was not altered when alcohol intake was considered. These findings confirm that the cardiovascular benefit of modest alcohol consumption. ADH1C genotype modifies the relationship between alcohol consumption and CHD risk but at lower levels than previously reported.

Influence of alpha-linolenic acid and fish-oil on markers of cardiovascular risk in subjects with an atherogenic lipoprotein phenotype.

We tested the hypothesis that dietary alpha-linolenic acid (ALA) can exert effects on markers of cardiovascular risk similar to that produced by its longer chain counterparts in fish-oil. A dietary intervention study was undertaken to examine the effects of an ALA-enriched diet in 57 men expressing an atherogenic lipoprotein phenotype (ALP). Subjects were randomly assigned to one of three diets enriched either with flaxseed oil (FXO: high ALA, n = 21), sunflower oil (SO: high linoleic acid, n = 17), or SO with fish-oil (SOF n = 19) for 12 weeks, resulting in dietary intake ratios of n-6:n-3 PUFA of 0.5, 27.9 and 5.2, respectively. The relative abundance of ALA and EPA in erythrocyte membranes increased on the FXO diet (p < 0.001), whereas both EPA and DHA increased after fish-oil (p < 0.001). There were significant decreases in total plasma cholesterol within (FXO -12.3%, p = 0.001; SOF -7.6%, p = 0.014; SO -7.3%, p = 0.033) and between diets (p = 0.019), and decreases within diets after 12 weeks for HDL cholesterol on flaxseed oil (FXO -10%, p=0.009), plasma TG (-23%, p < 0.001) and small, dense LDL (-22% p = 0.003) in fish-oil. Membrane DHA levels were inversely associated with the changes in plasma TG ( p= 0.001) and small, dense LDL (p<0.05) after fish-oil. In conclusion, fish-oil produced predictable changes in plasma lipids and small, dense LDL (sdLDL) that were not reproduced by the ALA-enriched diet. Membrane DHA levels appeared to be an important determinant of these fish-oil-induced effects.