Dietary cholesterol, eggs and coronary heart disease risk in perspective

Summary  The idea that dietary cholesterol increases risk of coronary heart disease (CHD) by turning into blood cholesterol is compelling in much the same way that fish oil improves arthritis by lubricating our joints! Dietary cholesterol, chiefly in the form of eggs, has long been outlawed as a causative agent in CHD through its association with serum cholesterol. However, the scientific evidence to support a role for dietary cholesterol in CHD is relatively insubstantial in comparison with the incontrovertible link between its circulating blood relative in low density lipoprotein (LDL) cholesterol and CHD. Interpretation of the relationship between dietary cholesterol and CHD has been repeatedly confounded by an often inseparable relationship between dietary cholesterol and saturated fat. It has also been exaggerated by the feeding of unphysiologically high intakes of eggs. Nonetheless, numerous studies have shown that dietary cholesterol can increase serum LDL-cholesterol, but the size of this effect is highly variable between individuals and, according to over 30 years of prospective epidemiology, has no clinically significant impact on CHD risk. Variation in response to dietary cholesterol is a real phenomenon and we can now identify nutrient–gene interactions that give rise to this variation through differences in cholesterol homeostasis. More importantly, to view eggs solely in terms of the effects of their dietary cholesterol on serum cholesterol is to ignore the potential benefits of egg consumption on coronary risk factors, including obesity, diabetes and metabolic syndrome. Cardiovascular risk in these conditions is largely independent of LDL-cholesterol. These conditions are also relatively unresponsive to any LDL-cholesterol raising effects of dietary cholesterol. Treatment is focused primarily on weight loss, and it is in this respect that eggs may have a new and emerging role in facilitating weight loss through increased satiety.     

冠心病基因检测与冠心病的关联性

目的观察冠心病基因检测与冠心病是否有关联性,以及关联程度如何。方法选取120例住院患者,其中60例为冠心病人,60例为非冠心病人。年龄40—65岁。冠心病为观察A组,非冠心病为对照B组,记录性别、年龄、冠心病家族史、高血压史、糖尿病史,并均抽血行冠心病基因检测。A组选1人和B组选1人按年龄相近、性别相同配对,共形成60对。开始进行1：1条件Logistic回归分析。结果冠心病家族史、高血压史、糖尿病史、以及冠心病基因检测与冠心病均有关联性。其中冠心病基因检测与冠心病的关联程度低于其他3个因素。结论冠心病基因检测与冠心病有关联性。     

Plasma concentrations of plant sterols: physiology and relationship with coronary heart disease

Recently, it has been questioned whether elevated levels of circulating plant sterols increase the risk of coronary heart disease (CHD). To date, no definitive conclusions regarding such a relationship have been reached, nor have there been any studies summarizing the factors that contribute to the observed elevations in plant sterol concentrations in plasma. Thus, the purpose of this review is to systematically compare the plant sterol levels of subjects from the general population and to describe factors that contribute to the variations observed. The question of whether elevated plasma concentrations of plant sterols are associated with an increased risk of CHD was also assessed. Results indicate that the key factors accounting for variations in circulating plant sterol concentrations include: apolipoprotein E phenotypes, ATP-binding cassette transporter polymorphisms, use of statin drugs, presence of metabolic syndrome, dietary intake of plant sterols, gender, and analytical techniques used in the measurement of plant sterols in the plasma. An analysis of the studies examining the relationship between circulating levels of plant sterols and CHD risk in non-sitosterolemic populations revealed no clear associations. Furthermore, it was shown that the above-mentioned factors play an important role in determining the levels of plant sterols in plasma. Since these factors may act as potential confounders, they must be controlled for before more solid conclusions can be reached.     

Secondary prevention in coronary heart disease

After myocardial infarction, beta-blockers, aspirin and (in selected patients) ACE inhibitors all reduce substantially the risk of further myocardial infarction or coronary death. With regard to life-style changes, giving up cigarette smoking reduces coronary risk by about 50%. Weight reduction and regular exercise are advised, although the effect of these measures on prognosis is uncertain. Recently, two major trials, the Scandinavian Simvastatin and West of Scotland Pravastatin studies, have radically changed ordinary medical practice. In these trials HMG CoA reductase inhibitor (statin) treatment reduced coronary events by 30–40%, reduced all-cause mortality, and proved safe and well-tolerated. The accepted policy now is to treat all patients with coronary heart disease, who have a cholesterol concentration 5.5 mmol/l or higher, with a statin. Where does this leave cholesterol-lowering dietary advice in secondary prevention? The benefits of statin treatment were attained by reducing serum cholesterol by an average of 25%. Diet change rarely attains such a fall in cholesterol and should therefore be used only as an adjunct to drug therapy. When recommending a lipid-lowering diet there is a danger that patients may be denied highly-effective drug treatment because of the «threshold» effect. A decision on the need for cholesterol reduction should be made before diet change is advised. Once the decision is made the target is a 25% cholesterol reduction, which will require drug therapy in addition to diet changes.     

Colesevelam hydrochloride: reducing atherosclerotic coronary heart disease risk factors

Colesevelam HCl is a bile acid sequestrant (BAS) which has been specifically designed with a unique structure for the purpose of improving tolerability and reducing potential drug interactions compared to older BAS, such as cholestyramine and colestipol. As a class, BAS are known to reduce cholesterol and glucose levels, and to reduce atherosclerotic coronary heart disease (CHD) risk as monotherapy, and in combination with other lipid-altering drug therapies. Colesevelam HCl has specifically been shown to reduce total and low-density lipoprotein (LDL) cholesterol levels, and has been approved as a cholesterol-lowering drug since year 2000. It has also been shown to reduce glucose levels. This discussion reviews mechanisms by which BAS lower cholesterol, and potential mechanisms by which BAS lower glucose levels in patients with type 2 diabetes mellitus. Finally this paper specifically reviews colesevelam HCl's pharmacology, lipid and glucose efficacy, safety/tolerability, and clinical use.     

Leg length, insulin resistance, and coronary heart disease risk: The Caerphilly Study

BACKGROUND: Adult height has been inversely associated with coronary heart disease risk in several studies. The mechanism for this association is not well understood, however, and this was investigated by examining components of stature, cardiovascular disease risk factors and subsequent coronary heart disease in a prospective study. METHODS: All men aged 45-59 years living in the town of Caerphilly, South Wales were approached, and 2512 (89%) responded and underwent a detailed examination, which included measurement of height and sitting height (from which an estimate of leg length was derived). Participants were followed up through repeat examinations and the cumulative incidence of coronary heart disease-both fatal and non-fatal-over a 15 year follow up period is the end point in this report. RESULTS: Cross sectional associations between cardiovascular risk factors and components of stature (total height, leg length and trunk length) demonstrated that factors related to the insulin resistance syndrome-the homeostasis model assessment of insulin resistance, fasting triglyceride levels and total to HDL cholesterol ratio-were less favourable in men with shorter legs, while showing reverse or no associations with trunk length. Fibrinogen levels were inversely associated with leg length and showed a weaker association with trunk length. Forced expiratory volume in one second was unrelated to leg length but strongly positively associated to trunk length. Other risk factors showed little association with components of stature. The risk of coronary heart disease was inversely related to leg length but showed little association with trunk length. CONCLUSION: Leg length is the component of stature related to insulin resistance and coronary heart disease risk. As leg length is unrelated to lung function measures it is unlikely that these can explain the association in this cohort. Factors that influence leg length in adulthood-including nutrition, other influences on growth in early life, genetic and epigenetic influences-merit further investigation in this regard. The reported associations suggest that pre-adult influences are important in the aetiology of coronary heart disease and insulin resistance.     

Postprandial lipaemia – the influence of diet and its link to coronary heart disease

Summary  Coronary heart disease (CHD) is the leading cause of death worldwide, and dietary fat intake is one of the major environmental risk factors implicated in its causation. In the drive to prevent CHD, much attention has focused on reducing the amount of energy derived from fat in the diet. However, little attention has been given to the amount of fat consumed in an individual meal and its postprandial effects. Postprandial lipaemia is the term used to describe the series of metabolic events that occur following the consumption of a fatty meal. The extent of postprandial lipaemia is indicated by the size or duration of the increase in plasma triacylglycerol (TAG) concentrations. There is evidence to indicate that exaggerated postprandial lipaemia is linked to an increased risk of CHD. There are several mechanisms by which it may influence the pathological processes that result in CHD, including effects on lipoproteins involved in atherosclerosis and acute effects on haemostatic function . The postprandial response to dietary fat is influenced by non-dietary factors (such as age, gender and activity level) as well as background diet and the amount and type of fat consumed in a meal. This review focuses on the mechanisms linking postprandial lipaemia and CHD risk and the factors affecting the level of postprandial lipaemia.     

Screening for coronary heart disease in elderly men based on current and past cholesterol levels

Efficient use of cholesterol measurements to screen for coronary heart disease in the elderly is not well defined. The purpose of this report is to examine such screening based on national guidelines in a sample of older men. Since relations between cholesterol and coronary heart disease are better established in those who are younger, screening in the elderly will also consider levels of cholesterol that existed earlier in life. Data are from a prospective study of 1,170 men enrolled in the Honolulu Heart Program who were followed over a 12-year period for coronary heart disease. Follow-up began from 1980 to 1982, when cholesterol levels were determined in men who were aged 61 to 81 years. Past cholesterol levels were measured 10 years earlier (1970–1972). During the course of follow-up, coronary heart disease developed in 117 of the men. Risk of disease rose significantly (P = 0.003) with increases in past cholesterol levels (1970–1972) but not with more recent levels (1980–1982). For men with current cholesterol levels that were desirable (<5.2 mmol/L [200 mg/dl], as defined by guidelines from the National Cholesterol Education Program), disease incidence continued to rise with increasing past cholesterol levels (P < 0.001). Accounting for high-density lipoprotein cholesterol and other screening factors did little to alter these findings. We conclude that desirable cholesterol levels in the elderly may not be a marker of a healthy risk profile if past cholesterol levels were high. Screening for coronary heart disease in the elderly could be improved by considering past cholesterol levels, rather than just a single measurement in later life.     

代谢综合征血清超敏C反应蛋白与冠心病关系

目的探讨代谢综合征（MS）患者血清超敏C反应蛋白（hs—CRP）含量对冠心病的预测价值。方法在珠海市湾仔区6个社区中进行慢性病筛查，选择其中符合条件且资料完整的1362人，采集空腹血液样品，检测血清hs—CRP含量及相关生化指标，比较MS、冠心病患者血清hs—CRP浓度的差异。结果1362人中，确诊MS264例（19．4％），检出高血压病患者277例（20．3％），冠心病患者164例（12．0％）；其中MS患者中合并冠心病92例（34．8％）。咀清hs—CRP受年龄、体重、吸烟、血脂及血糖水平影响，差异均有统计学意义。高血压人群、冠心病人群和MS人群的血清hs—CRP含量均高于正常人群，差异均有统计学意义。校正年龄、体质指数、空腹血糖、总胆固醇、甘油三酯等影响因素后，hs—CRP为高血压、冠心病、MS的独立危险因素。代谢指标异常数量越多。合并冠心病可能性越大，hs—CRP含量越高。结论MS患者血清hs—CRP水平是合并冠心病的独立危险因子，可预示冠心病的发生。     

Risk factors for coronary heart disease among firefighters in Cincinnati

Since 1984, coronary heart disease (CHD) risk, factors have been prospectively assessed among Cincinnuti, firefighters, free of CHD at study entry. In total, 806 firemen with a mean age of 37 years at entry have been, followed for 6.4 years on average, contributing 5,173 person-years. CHD risk, factors were measured every 1-4 years and included weight, blood pressure, cigarette use, fasting glucose, and lipid profile. When, in aggregate, these CHD risk, factors were, found to be in a high risk range, suggestions were made serially to reduce CHD risk. A composite high CHD risk factor score led to an exercise electrocardiogram (ECG) with thallium scan, which was repeated every 1-4 yeurs. Myocardial infarction (MI) occurred in 7 men, with 1.35 Mis/1,000 mean-years; 15 others developed CHD, with 4.25 MI + CHD/1,000 mean-years. The firefighters' MI event rate (1.35 MIS/1,000 man-years) was lower (but not significantly, p > 0.1) than that for employed 30- to 39-year-old men free of CHD at entry (2.07/1,000 man years), who had an average follow-up of 5.4 years in the NHANES I study. At study entry, the 22 men who later developed CHD (vs. the 784 who did not develop CHD) were older (p=.0001), smoked more (p=.001), and were more likely to have first degree relatives with CHD before age 60 (p=.017). After covariance adjusting for age, race, and Quetelet index, men with CHD (vs. those CHD free) had higher systolic and diastolic blood pressures (p=.0001,.0001), higher LDL cholesterol (p=.04), higher total cholesterol (p=.014), and higher triglycerides (p=.03). By Poisson regression, significant independent predictors of CHD events were age (p=.0007), cigarette smoking (p=.001), diastolic blood pressure (p=.056), and family history of CHD at ave ≤60 (p=.048). Men who later developmed CHD and those without CHD did not differ by histroy of smoke inhalation (p > 0.3). The calculated ratio of savings to cost attributable to the program per year was 5.9/1 ($258.500/$43,600). In the current study, firefighting as an occupation was not associated with increased CHD event rates. CHD events that did develop were, for the most part, associated with modifiable CHD risk factors.     

冠心病患者血管内皮功能紊乱与血清胆红素水平分析

目的探讨不同程度冠心病患者血管内皮功能紊乱程度与血清胆红素水平。方法选择冠心病患者143例,分为单支病变组(A组)56例、双支病变组(B组)48例、多支病变组(C组)39例。选择同期参与健康体检的40例健康人群为对照组(D组)。分别检测血胆红素及VEGF、ET-1、NO水平。结果 A组IBIL、DBIL、TBIL较D组均有显著性差异(P0.05),B组IBIL较A、D组有显著性差异(P0.05),DBIL、TBIL较D组均有显著性差异(P0.05),C组IBIL、DBIL、TBIL较A、D组均有显著性差异(P0.05)。A组VEGF、ET-1、NO较D组均有显著性差异(P0.05),B组VEGF、ET-1较A、D组有显著性差异(P0.05),NO较D组均有显著性差异(P0.05),C组VEGF、ET-1、NO较A、D组均有显著性差异(P0.05)。IBIL与VEGF、ET-1、NO显著相关(P0.05),DBIL与VEGF、ET-1显著相关(P0.05),TBIL与VEGF、ET-1显著相关(P0.05)。结论胆红素代谢异常与血管内皮功能紊乱密切相关,是导致冠状动脉粥样硬化的重要因素。     

女性冠心病临床及冠状动脉病变特点分析

目的 了解女性冠心病的临床与冠状动脉(冠脉)病变特点,以提高诊断水平。方法 以男性为对照,回顾性分析135例女性冠心病患者的临床资料及冠脉造影结果。结果 年龄<60岁,女性冠心病检出率明显低于男性;年龄≥60岁,女性明显高于男性。年龄<60岁,女性患病平均年龄较男性晚(56.4±3.2岁 vx47.4±6.2岁,P<0.05);有高血压病者显著高于男性,但糖尿病、高脂血症无显著性差异,发病时临床症状不典型,心电图ST-T改变不明显,冠脉病变较轻。年龄≥60岁时,女性冠心病有高脂血症者显著高于男性,两组高血压病、糖尿病无差异,临床症状比较典型,特异性ST-T改变仍不明显,但冠脉病变较严重,单支血管(前降支)病变减少。结论 女性冠心病临床症状多不典型,随着年龄增长,女性冠心病检出率显著增加,冠脉病变逐渐加重,应及早做冠脉造影检查以明确诊断。     

超敏C反应蛋白、脂蛋白(a)、总胆固醇与高密度脂蛋白胆固醇比值在冠心病检测中的意义

目的 分析血清超敏C反应蛋白(hs-CRP)、脂蛋白(a)[Lp(a)]、总胆固醇(TC)与高密度脂蛋白胆固醇(HDL-C)比值在冠心病检测中的临床意义.方法 2010年9月至2011年9月,分别检测176例冠心病患者(冠心病组,其中急性心肌梗死56例,稳定型心绞痛58例,不稳定型心绞痛62例)以及60例健康对照者(对照组)血清hs-CRP、Lp(a)水平和TC/HDL-C.结果 冠心病组血清hs-CRP、Lp (a)和TC/HDL-C分别为(34.51±9.65) mg/L、(295.16±104.57) mg/L和4.23±0.91,而对照组分别为( 1.26±0.69) mg/L、(145.26±42.19) mg/L和2.54±0.57,两组比较差异有统计学意义(P＜ 0.05).急性心肌梗死患者血清hs-CRP、Lp(a)和TC/HDL-C明显高于不稳定型心绞痛患者和稳定型心绞痛患者(P＜ 0.05);不稳定型心绞痛患者血清hs-CRP、Lp(a)和TC/HDL-C明显高于稳定型心绞痛患者(P＜ 0.05).结论血清hs-CRP、Lp(a)和TC/HDL-C在冠心病患者中明显升高,可以反映冠心病的严重程度.     

疾病家族史与冠心病发生风险的关联研究

目的 分析疾病家族史对急性冠心病事件（MCE）及缺血性心脏病（IHD）发病风险的影响。方法 研究对象来自中国慢性病前瞻性研究,剔除基线时患有恶性肿瘤、心脏病及脑卒中的个体,纳入485 784人进行分析。统计分析采用Cox比例风险模型。结果 研究人群随访M=7.2年,随访期间新发MCE 3 934例,IHD 24 537例。与无家族史者相比,有家族史者发生MCE及IHD的风险均较高,HR值（95% CI）分别为1.41（1.19~1.65）和1.25（1.18~1.33）。与双亲型家族史相比,同胞型家族史与早发MCE的关联更强（HR=2.97,95% CI：1.80~4.88）;超重/肥胖者中家族史与MCE、IHD的关联更强;吸烟者中家族史与MCE的关联更强。结论 有家族史者发生MCE及IHD的风险较高。结果提示应鼓励个体根据疾病家族史信息,及早开展生活方式干预和相关基础疾病的治疗管理。     

老年冠心病冠脉支架再狭窄相关因素调查

目的研究老年人冠脉病变的特点及支架植入后再狭窄的发生情况及相关因素。方法随机选择冠脉造影资料较全的老年冠心病患者150例，分析冠脉病变特点．并对其中复查冠脉造影的96例患者再狭窄情况，及再狭窄相关因素（年龄、性别、高血压、糖尿病、高血脂及冠脉病变特点、支架性质）进行分析。结果老年人多支病变多见75．3％，再狭窄率26.3％，其中裸支架再狭窄率36．1％（13／36），紫杉醇23_3％（7／30），雷帕霉素16．7％（5／30）。狭窄及无狭窄组患者的年龄、血脂差异无统计学意义。两组糖尿病病例数、支架长度、支架数量差异具有统计学意义，裸支架组的再狭窄率明显高于药物洗脱支架组。结论糖尿病、支架长度、多个支架、支架性质均为再狭窄的相关因素。     

Implications of the obesity epidemic for lipid-lowering therapy: non-HDL cholesterol should replace LDL cholesterol as the primary therapeutic target

Obesity, metabolic syndrome and diabetes are conditions with increasing prevalence around the world. Cardiovascular risk in diabetics is often so high as to overlap with event rates observed in those with established coronary disease and this has lead to diabetes being classified as a coronary risk equivalent. However, despite the elevated risk of cardiovascular events associated with diabetes and the metabolic syndrome, these patients often have normal low density lipoprotein (LDL) cholesterol despite frequent increases in apolipoprotein B, triglycerides and nonhigh density lipoprotein (HDL) cholesterol. In contrast to LDL cholesterol, non-HDL cholesterol represents cardiovascular risk across all patient populations but is currently only recommended as a secondary target of therapy by the ATP III report for patients with hypertriglyceridemia. This article provides an overview of the studies that shown non-HDL cholesterol to be superior to LDL cholesterol in predicting cardiovascular events and presents the case for non-HDL cholesterol being the more appropriate primary target of therapy in the context of the obesity pandemic. Adopting non-HDL cholesterol as the primary therapeutic target for all patients will conceivably lead to an appropriate intensification of therapy for high risk patients with low LDL cholesterol.     

Family history of ischemic heart disease with respect to mean twin-pair cholesterol and subsequent ischemic heart disease in the NHLBI twin study

This study examines the independent and interactive effects of family history scores (FHxS) for the prevalence of ischemic heart disease with plasma lipids and subsequent morbidity and mortality from ischemic heart disease. FHxS were calculated for 514 sets of middle aged male twins who participated in the entry examination of the NHLBI Veteran twin study in 1969-1973. Comparison of the FHxS with the level of plasma total cholesterol and HDL cholesterol (HDLc) paralleled earlier reported findings in young adults; individuals with high total cholesterol in two exams 8-12 years apart had significantly (P less than .01) higher FHxS. The same relationship was noted when using the mean twin-pair cholesterol level at the initial exam when the twins were in their 40s. Using the pair means over two exams as the cotwins aged into their 50s, the association of FHxS with total cholesterol declined and pairs with HDLc persistently in the highest quintile at both exams had significantly (P less than .01) lower FHxS. The changes in the pattern of association of lipid fractions with FHxS with age parallel the reported age decline of total cholesterol as a risk factor for heart disease. Assessment of ischemic heart disease events up to January 1988 revealed a highly significant association (P less than .0001) of later ischemic heart disease events with FHxS. At each level of lipid categorization pairs who later had events had higher FHxS than those without any subsequent heart disease; these differences were significant in all but the low risk lipid groups (low total cholesterol, high HDLc, and low total cholesterol/HDLc ratio). We conclude that FHxS is related to total cholesterol and HDLc but also is an independent predictor of subsequent ischemic heart disease after 14-18 years of follow-up.     

Explaining the social gradient in coronary heart disease: comparing relative and absolute risk approaches

STUDY OBJECTIVES: There are contradictory perspectives on the importance of conventional coronary heart disease (CHD) risk factors in explaining population levels and social gradients in CHD. This study examined the contribution of conventional CHD risk factors (smoking, hypertension, dyslipidaemia, and diabetes) to explaining population levels and to absolute and relative social inequalities in CHD. This was investigated in an entire population and by creating a low risk sub-population with no smoking, dyslipidaemia, diabetes, and hypertension to simulate what would happen to relative and social inequalities in CHD if conventional risk factors were removed. DESIGN, SETTING, AND PARTICIPANTS: Population based study of 2682 eastern Finnish men aged 42, 48, 54, 60 at baseline with 10.5 years average follow up of fatal (ICD9 codes 410-414) and non-fatal (MONICA criteria) CHD events. MAIN RESULTS: In the whole population, 94.6% of events occurred among men exposed to at least one conventional risk factor, with a PAR of 68%. Adjustment for conventional risk factors reduced relative social inequality by 24%. However, in a low risk population free from conventional risk factors, absolute social inequality reduced by 72%. CONCLUSIONS: Conventional risk factors explain the majority of absolute social inequality in CHD because conventional risk factors explain the vast majority of CHD cases in the population. However, the role of conventional risk factors in explaining relative social inequality was modest. This apparent paradox may arise in populations where inequalities in conventional risk factors between social groups are low, relative to the high levels of conventional risk factors within every social group. If the concern is to reduce the overall population health burden of CHD and the disproportionate population health burden associated with the social inequalities in CHD, then reducing conventional risk factors will do the job.     

老年冠心病患者血清中5种微量元素含量及其临床意义

对３８例老年冠心病患者及２９例老年健康者进行了血清５种微量元素检测，结果表明：老年冠心病患者血清锌、铜、锰、铬、硒５种微量元素均显著低于健康组，适量增加以上几种微量元素摄入量有利于冠心病的预防和治疗。     

Low-fat diets, triglycerides and coronary heart disease risk

Nutritionists are currently debating whether low‐fat high‐carbohydrate diets protect against coronary heart disease (CHD). Traditionally, low‐fat diets were prescribed because they reduce plasma and low density lipoprotein (LDL) cholesterol concentrations. However, there is considerable concern because low‐fat diets also increase plasma triglyceride (TG) and reduce high density lipoprotein (HDL) cholesterol concentrations. Recent prospective epidemiological studies have shown that these are independent risk factors for future CHD risk. It has been proposed that the adverse effects of low‐fat, high‐carbohydrate diets on TG and HDL may counteract or negate the beneficial effect of reducing LDL cholesterol concentrations. Although there is also strong epidemiological evidence that reduced total fat intake is not protective against CHD, high‐fat diets predispose to obesity and insulin resistance, both of which adversely affect TG metabolism. This review presents the evidence in relation to the importance of TG as a risk factor for CHD, and explains the pathophysiology that may underlie the aetiological role of TG metabolism in the pathogenesis and progression of CHD. It also addresses the physiological consequences of advocating low‐fat high‐carbohydrate diets, with particular reference to the effects on lipoprotein metabolism and CHD risk.