Effects of long-term vegetarian diets on cardiovascular autonomic functions in healthy postmenopausal women

The incidence of cardiovascular disease is higher in postmenopausal women than in premenopausal women. We hypothesized that long-term vegetarian diets might modulate cardiovascular autonomic functions measured by frequency-domain techniques in healthy postmenopausal women. A total of 35 healthy vegetarians (mean age +/- SEM 55.0 +/- 1.3 years) who had been vegetarians for > or =2 years and 35 omnivores (55.1 +/- 1.4 years) participated in this study. These subjects were all postmenopausal without hormone replacement therapy. Fluctuations in arterial blood pressure and heart rate variability were diffracted into low-frequency (0.04 to 0.15 Hz) and high-frequency (0.15 to 0.4 Hz) segments. Cardiovascular autonomic functions and baroreflex sensitivity were evaluated by specific frequency-domain measures. The vegetarians had statistically lower systolic and diastolic blood pressure, and lower serum total cholesterol, low-density lipoprotein cholesterol, triglycerides, fasting blood sugar, and hemoglobin levels compared with the nonvegetarians. They also exhibited a significantly higher high-frequency power of heart rate variability and increased baroreflex sensitivity than did omnivores. No statistical differences were found in the low-frequency/high-frequency ratio or percentage of low frequency of heart rate variability between the 2 groups. In conclusion, in addition to the lower blood pressure and lipid concentrations in vegetarians, long-term vegetarian diets may facilitate vagal regulation of the heart and increase baroreflex sensitivity in healthy postmenopausal women, without increasing the sympathetic modulations of the cardiovascular system.     

Apolipoprotein E levels in vegetarians

Vegetarians are known to have low lipoprotein lipid and apolipoprotein AI and B levels. Since dietary cholesterol has recently been shown to have important effects on apolipoprotein E (apo E) metabolism, we measured plasma apo E levels in three groups of vegetarians. Group I (n = 36) consumed < 10 mg cholesterol daily and 42% of calories as fat (P:S ratio 2.6). Group II (n = 10) and Group III (n = 18) consumed 97 and 179 mg cholesterol daily, and 35% of calories as fat (P:S ratios 0.7 and 0.9) respectively. Compared to control values, vegetarian plasma cholesterol and triglyceride levels were decreased by 10%–30% and 30%–55%. Plasma apo E levels were decreased equally in all groups by 35% (2.4 ± 0.1 mg/dl versus 3.6 ± 0.1 mg/dl, p < .001). Plasma apo E levels were increased in parallel with lipid levels in pregnant vegetarians but were not different from non-lactating vegetarians in postpartum lactating women. Decreased apo E levels did not correlate with relative body weight, P:S ratio or intake of fat, carbohydrates or protein. Since all vegetarian diets studied were low cholesterol diets, decreased cholesterol intake may contribute to the low apo E levels. The apparent modification of apo E metabolism by vegetarian diets may be important in mediating effects of lipid lowering diets on atherogenesis.     

Lipoprotein risk factors in vegetarian women of Indian descent are unrelated to dietary intake.

Dietary intakes, anthropometric indices and plasma lipoprotein and alpha-tocopherol concentrations were measured in premenopausal vegetarian women of Indian descent (n = 22) and in white women of European descent consuming either mixed (n = 22) or vegetarian diets (n = 18). The Indian women were shorter in height than the white women and had a higher proportion of body fat. Energy intakes were lower in the Indian women, both in absolute terms and per kg body weight. The proportion of energy derived from saturated fatty acids was lower and that from polyunsaturated fatty acids was greater in both Indian and white vegetarians compared with the subjects on mixed diets. Intakes of dietary fibre and vitamins C and E were higher in the white vegetarians compared with the other groups. Plasma concentrations of total and LDL cholesterol and apolipoprotein B and the ratio of apolipoprotein B/apolipoprotein AI were lower and HDL and HDL2 cholesterol, alpha-tocopherol concentrations and the ratio of alpha-tocopherol/cholesterol were greater in the white vegetarian group than in the other groups. Total plasma cholesterol was associated with measures of truncal obesity, especially subscapular skinfold thickness and the percentage energy derived from saturated fatty acids. Plasma concentrations of apo(a) were higher and those of HDL and HDL2 cholesterol and sex hormone binding globulin (SHBG) were lower in the Indian vegetarian women compared with both groups of white women. No relationship could be found between apo(a), HDL and HDL2 cholesterol concentration and nutrient intake but HDL and HDL2 were negatively associated with the proportion of body fat and apo(a) weakly with subscapular skinfold thickness.(ABSTRACT TRUNCATED AT 250 WORDS)     

Importance of HDL cholesterol levels and the total/ HDL cholesterol ratio as a risk factor for coronary heart disease in molecularly defined heterozygous familial hypercholesterolaemia.

AIMS: To assess the relationship of the lipid profile to coronary heart disease in a group of heterozygous familial hypercholesterolaemic subjects with similar age, sex, body mass index, prevalence of angiotensin converting enzyme DD genotype and type of low density lipoprotein receptor mutation. METHODS AND RESULTS: A total of 66 molecularly defined heterozygous familial hypercholesterolaemic subjects, 33 of whom had coronary heart disease, were studied. Clinical features, cardiovascular risk factors and lipid parameters were compared in both groups. Familial hypercholesterolaemic patients with coronary heart disease showed significantly lower values of mean plasma HDL cholesterol and a higher total/HDL cholesterol ratio as compared with familial hypercholesterolaemic subjects free of coronary heart disease. Total and LDL cholesterol concentrations were higher in patients with coronary heart disease, without reaching statistical significance. No differences in plasma lipoprotein(a) levels on absolute and log-transformed values were observed between the two groups. In the whole familial hypercholesterolaemia group, plasma HDL cholesterol levels were related to plasma triglyceride values and to LDL receptor gene 'null mutations'. CONCLUSIONS: In familial hypercholesterolaemic subjects of similar age, gender, body mass index, systolic and diastolic blood pressure, and genetic factors that could influence coronary heart disease risk, plasma HDL cholesterol values and total/HDL cholesterol ratios are two important coronary risk factors. Hence, treatment of familial hypercholesterolaemia should focus not only on lowering total and LDL cholesterol levels, but also on increasing HDL cholesterol values for coronary heart disease prevention. More prospective and intervention trials should be conducted to establish the relationship of HDL cholesterol levels and coronary heart disease in familial hypercholesterolaemia.     

ApoA-I/ApoA-II ratios in plasmas of vegetarians

Diets low in fat and cholesterol and high in P/S ratio are accompanied by low HDL-cholesterol levels. Short-term experimental feeding of such diets demonstrates that the HDL2 fraction is reduced preferentially. In order to ascertain whether the HDL2 lowering effects persist over the long-term, apolipoprotein A-I/A-II ratios, which are indices of the HDL2 relative to HDL3 in plasma, were measured in three groups of vegetarians (n = 35) who had been eating vegetarian diets for 1 to more than 5 years varying in cholesterol contents from less than 10 to 300 mg/d, fat between 30% to 50% of calories, and P/S ratio between 0.7-2.5. Concentrations of apoA-I were lower in those eating the least cholesterol and the highest P/S ratio, ie, apoA-I correlated positively with dietary cholesterol (r = 0.38, P less than 0.05), and both apoA-I and the A-I and the A-I/A-II ratio correlated negatively with the ratio of polyunsaturated-to-saturated (P/S) fatty acids (r = -0.39, P less than 0.05, and r = -0.41, P less than 0.02, respectively). There was no significant correlation between apoA-I, apoA-II, the A-I/A-II ratio or the high-density lipoprotein cholesterol/apoA-I ratio and consumption of total calories, fat, protein, or carbohydrate. Since the A-I/A-II ratio is much higher in HDL2 than in HDL3, these data suggest that cholesterol intake and the P/S ratio are important long-term dietary determinants of plasma HDL2 levels. Thus, in vegetarians, despite a reduced risk of coronary heart disease, the high-density lipoprotein cholesterol (HDL-C) and especially HDL2 concentrations were low. More work is needed to elucidate this interesting paradox.     

Consistently high plasma high-density lipoprotein-cholesterol levels in children in Spain, a country with low cardiovascular mortality

Coronary heart disease (CHD) mortality is relatively low in Spain compared with other developed countries and has remained low despite an apparent increase in mean plasma cholesterol concentration in adults over the last several years. It is accepted that pathologic processes related to arteriosclerosis development begin in childhood and seem to be related to the presence of cardiovascular risk factors at this age. High-density lipoprotein-cholesterol (HDL-C) levels in children have been inversely correlated with the incidence of coronary heart disease in the different countries studied. Childhood plasma lipoprotein profile might contribute to the low coronary heart disease mortality in Spain. Thus, we analyzed data on lipid levels over time in schoolchildren in Spain in the last decade. Plasma lipid levels were analyzed in prepuberal children (6 to 8 years) in 3 school-based surveys performed by our group in Madrid in 1987, 1993, and 1999. A significant increase in plasma total cholesterol (P < .05) and low-density lipoprotein-cholesterol (LDL-C) (P < .01) levels in prepuberal children was observed over the last decade. However, the mean concentration of plasma HDL-C remained stable and very high. These high levels of plasma HDL-C in Spanish school children may help to explain why the coronary heart disease mortality rate in Spain is low compared with that in other developed countries.     

微量元素与冠心病及其血脂的关系探讨

目的探讨微量元素与冠心病及其高血脂的关系.方法 用电感耦合等离子体原子发射光谱法测定了82例冠心病患者的6种微量元素变化,并与血脂做相关分析.结果示血清铁、锌、锌、铜比和铅在冠心病组较正常组明显增高,铬明显降低(P<0.01或0.001),铜和镉两组间无统计学差异.总胆固醇和低密度脂蛋白胆固醇分别与铁、锌、铅呈显著正相关,与铬呈显著负相关,高密度脂蛋白胆固醇与锌呈显著负相关(P<0.05或0.01).结论 提示部分微量元素的不平衡可能影响脂质代谢,并在冠心病中有重要发病学意义.     

Accumulation of apoE-enriched triglyceride-rich lipoproteins in patients with coronary artery disease

Triglycerides (TGs) are vehicled by multiple particles with different abilities to promote atherosclerosis. Among plasma TG-rich lipoproteins (TRLs), subspecies may or may not contain apolipoprotein E (apoE) molecules: in this study, we evaluated the relative contribution of apoE-rich and apoE-poor TRLs to coronary atherosclerosis. We selected a group of males with premature coronary artery disease (CAD) without any of the classical nonlipid risk factors and/or high plasma lipid levels and evaluated the plasma concentration of TRL subspecies in comparison with healthy controls. Patients with CAD and controls had total cholesterol and TG levels within the normal range (despite slightly, even if significantly, higher TG levels in patients with CAD) and low-density lipoprotein cholesterol levels near optimal values. Nevertheless, patients with CAD had significantly lower high-density lipoprotein cholesterol, smaller low-density lipoprotein peak particle size, and a reduced HDL2b subfraction than controls. In addition, we observed higher concentrations of total TRL in patients with CAD together with a selective increase in apoE-rich particles. All these data were confirmed after correction for TG levels. We also investigated which parameters were associated with the spread of coronary atherosclerosis. Subjects with a single-vessel disease had selectively lower levels of apoE-rich fractions than patients with a multivessel disease. This was confirmed by multivariate analysis. Patients with a premature CAD free of nonlipid conventional risk factors, despite not having elevated lipid levels, show several lipoprotein abnormalities. Besides known atherogenic alterations, the accumulation of apoE-rich TRL subfractions may represent an additive factor that can potentially promote and initiate the atherosclerotic process.     

Fish intake, independent of apo(a) size, accounts for lower plasma lipoprotein(a) levels in Bantu fishermen of Tanzania: The Lugalawa Study.

Plasma lipoprotein(a) [Lp(a)] levels are largely genetically determined by sequences linked to the gene encoding apolipoprotein(a) [apo(a)], the distinct protein component of Lp(a). Apo(a) is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. In 2 racially homogeneous Bantu populations from Tanzania differing in their dietary habits, we found that median plasma levels of Lp(a) were 48% lower in those living on a fish diet than in those living on a vegetarian diet. Considering the relationship between apo(a) size and Lp(a) plasma concentration, we have extensively evaluated apo(a) isoform distribution in the 2 populations to determine the impact of apo(a) size in the determination of Lp(a) values. The majority of individuals (82% of the fishermen and 80% of the vegetarians) had 2 expressed apo(a) alleles. Additionally, the fishermen had a high frequency of large apo(a) isoforms, whereas a higher frequency of small isoforms was found in the vegetarians. When subjects from the 2 groups were matched for apo(a) phenotype, the median Lp(a) value was 40% lower in Bantus on the fish diet than in those on the vegetarian diet. A significant inverse relationship was also found between plasma n-3 polyunsaturated fatty acids and Lp(a) levels (r=-0.24, P=0.01). The results of this study are consistent with the concept that a diet rich in n-3 polyunsaturated fatty acids, and not genetic differences, is responsible for the lower plasma levels of Lp(a) in the fish-eating Bantus and strongly suggest that a sustained fish-based diet is able to lower plasma levels of Lp(a).     

Platelet fatty acids and function in two distinct regions of Belgium: relationship to age and dietary habits

We compared the dietary habits, fatty acid composition of plasma and platelet phospholipids, and platelet function in two groups of healthy Belgian male subjects, known to differ in their mortality rate from coronary heart disease (CHD). In the Walloon subjects, there was a larger intake of saturated and a lower intake of (n-6) polyunsaturated fats, confirmed by the fatty acid composition of plasma and platelet phospholipids. While plasma HDL and total cholesterol were similar in the present samples of the two communities, platelet aggregation to epinephrine was significantly higher in the Walloon subjects. When the two populations were divided into younger (28-54 years) and older (55-73 years) age groups, the older Walloon subjects exhibited platelet hyper-aggregability to most of the agonists, compared to the other three groups. In addition to dietary fats, alcohol and smoking habits, age was an important determinant of platelet phospholipid fatty acids and platelet reactivity. The present results reinforce those of previous studies, indicating that platelet behaviour is significantly affected by the main risk factors for CHD.     

European lipid guidelines: therapeutic recommendations. European Atherosclerosis Society

The European Consensus Conference has classified persons with hyperlipidemia into 5 groups on the basis of cholesterol and triglyceride levels. Plasma cholesterol concentration alone is not sufficient for the assessment of myocardial infarction risk; other risk factors must be considered for a more sensitive prediction. Guidelines for risk assessment of coronary heart disease and treatment regimens for each of the 5 hyperlipidemia groups, as outlined in the Policy Statement on coronary heart disease of the European Atherosclerosis Society, are described. It is emphasized that therapeutic goals for patients with hyperlipidemia depend to some extent on the presence or absence of other risk factors; plasma cholesterol and low-density lipoprotein cholesterol target levels may be lower in those with associated risk factors.     

脂源性激素促酰化蛋白在冠心病患者中的变化及意义

为探讨冠心病患者血浆中脂源性激素促酰化蛋白浓度的变化,并进一步研究促酰化蛋白与冠心病患者血脂变化的相关性,收集冠心病患者62例,正常健康者47例,记录临床资料,包括身高、体重、性别、年龄和血压,采用酶联免疫吸附法检测血浆促酰化蛋白浓度,并用酶法检测总胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白、载脂蛋白A1和载脂蛋白B100水平.结果发现,冠心病患者促酰化蛋白浓度明显高于正常对照组,差异有显著性(P＜0.05).冠心病组体重指数、血压及血浆总胆固醇、甘油三酯、低密度脂蛋白、高密度脂蛋白及载脂蛋白B100水平与正常对照组相比均存在显著性差异(P＜0.05).冠心病患者血浆促酰化蛋白与体重指数、总胆固醇、甘油三酯、低密度脂蛋白、载脂蛋白B100呈显著正相关(分别为r=0.42,P＜0.01;r=0.36,P＜0.01;r=0.20,P＜0.05;r=0.31,P＜0.05;r=0.45,P＜0.01).结果提示,促酰化蛋白参与了冠心痛患者脂质代谢紊乱的发生,血浆促酰化蛋白水平可作为评估冠心病发病危险因素的一项新指标.     

早发冠心病心肌梗死型与非心肌梗死型危险因素差异分析

目的探讨早发冠心病中心肌梗死型与非心肌梗死型的危险因素差异。方法回顾性分析2004年1月至2009年12月在沈阳医学院附属奉天医院心血管内科住院并确诊的45岁及以下冠心病患者165例,分为急性心肌梗死(AMI)组和非AMI组。对两组患者的相关临床资料及危险因素进行统计分析。结果 AMI组吸烟史比例、男性比率、血浆纤维蛋白原及D-二聚体均高于非AMI组,差异有统计学意义(P<0.05),两组的血脂异常率、血小板计数(PLT)、血小板压积、凝血酶原时间(PT)、国际标准化比值(INR)和活化部分凝血活酶时间(APTT)的差异无统计学意义。结论吸烟、男性性别、血脂水平异常是早发冠心病重要危险因素;血浆纤维蛋白原水平增高对于预测早发冠心病心肌梗死可能具有一定的临床意义。     

Platelet fatty acids in coronary heart disease, dyslipidemia, hypertension and healthy controls

A cross-sectional study was performed to investigate 250 volunteers from Pramongkutklao Hospital, Samphanthawong district, Wat Chaiyapreukmala and Wat Pradoo in Taling Chan district. They were divided into groups of 35 apparently healthy males, 16 males with coronary heart disease, 37 males with dyslipidemia and 9 males with hypertension with age ranges of 24-62, 56-69, 25-69 and 26-75 years, respectively. The female groups were composed of 55 apparently healthy females, 10 females with coronary heart disease, 73 females with dyslipidemia and 15 females with hypertension with age ranges of 27-65, 33-67, 22-73 and 38-70 years, respectively. Platelet fatty acids levels were found to have no significant difference between the different male groups. In the female groups, the alpha-linolenic acid (ALA) level in hypertension was significantly higher than in coronary heart disease (CHD) (p<0.05), whereas the arachidonic acid (AA) level in hypertension was significantly higher than in the apparently healthy females (p<0.05). No correlation was found between platelet fatty acids and age or anthropometric parameters, which indicate that platelet fatty acids may not depend on either age or anthropometric parameters. Positive correlations were shown between ALA and eicosapentaenoic acid (EPA), AA and docosahexaenoic acid (DHA), ALA and the diastolic blood pressure, DHA and total cholesterol (TC), and between low density lipoprotein choleoterol (LDL-C) and plasma glucose. Negative correlations were shown between LA and EPA, AA and EPA, EPA and DHA, EPA and the systolic blood pressure, and AA and the diastolic blood pressure.     

Plasma lipoprotein concentrations in ethnic populations

There is a complex interplay between genetic and environmental factors that influences the expression of plasma lipoprotein levels. It is therefore not surprising that differences in lipid levels have been reported between ethnic groups. There are conflicting data on racial and ethnic variations in lipids, and also limited data on the relationship between lipoprotein levels and coronary heart disease risk in specific populations. This review summarizes available data on ethnic variations in plasma lipoproteins and the potential impact on coronary morbidity and mortality.     

Age-dependence of lipid parameters in the general population and vegetarians

Age-dependent changes of lipid metabolism may arise both as a result of mechanisms of biological ageing and factors influencing age-dependent changes. To study possible influences of nutrition and life-style of vegetarians on age-dependence of lipid parameters, subjects of general population were compared with vegetarians. In the frame of population-based lipid screening projects in the city of Leipzig/Germany (Lipid Study Leipzig, LSL) 10 550 subjects (3,816 men and 6,734 women, age 18-99 years) of general population were compared with 417 vegetarians (vegans, lacto-vegetarians, lacto-ovo-vegetarians, 148 men and 269 women, age 18-93 years). Most of the vegetarians included in the study were members of the German Society of Vegetarians. The study program included capillary blood cholesterol measurements and the determination of high-density lipoprotein (HDL)-cholesterol, the measurement of other cardiovascular risk factors and the evaluation of dietary and life-style factors. Evaluation of cardiovascular risk profile within LSL was connected with individual consultation.The mean total cholesterol and non-HDL-cholesterol level and the total: HDL-cholesterol ratio showed the expected age-dependence, with maximum values within the decade 60-70 years. Vegetarians showed lower total and non-HDL-cholesterol levels in comparison with the general population. Furthermore, the age-dependent increase of these parameters is less pronounced under the conditions of vegetarian nutrition and life-style. Especially in young adulthood a significant difference is observed. Thus, the results of the present study reveal the role of nutritional and life-style factors that determine the lipid profile on a population basis and suggest that the known age-dependent rise of the level of atherogenic plasma lipoproteins is partly preventable.     

High-density lipoprotein and coronary heart disease: lessons from recent intervention trials

Epidemiologic studies have consistently implicated low plasma high-density lipoprotein cholesterol as an important, independent risk factor for the development of coronary heart disease. However, clinical trials specifically designed to evaluate the role of lipid therapy in patients with low high-density lipoprotein cholesterol have only been recently reported. They include two trials with angiographic end points, the Lopid Coronary Angiography Trial and the Bezafibrate Coronary Atherosclerosis Intervention Trial, and three clinical end points trials, the Air Force/Texas Coronary Atherosclerosis Prevention study, the Department of Veterans Affairs High-Density Lipoprotein Intervention Trial, and the Bezafibrate Infarction Prevention study. These and other trials clearly indicate that persons with coronary heart disease and high low-density lipoprotein cholesterol (>130 mg/dL [3.36 mmol/L]), with or without low high-density lipoprotein cholesterol, benefit from statin therapy. The Air Force/Texas Coronary Atherosclerosis Prevention study showed that persons at high risk of coronary heart disease but without known disease, who have moderate levels of low-density lipoprotein cholesterol as well as low levels of high-density lipoprotein cholesterol, also appear to benefit from statin therapy although the cost effectiveness of this approach is unclear. The results from the Department of Veterans Affairs High Density Lipoprotein Intervention Trial provide convincing evidence that patients without high low-density lipoprotein cholesterol and with established coronary heart disease and low high-density lipoprotein cholesterol benefit from gemfibrozil. This drug may be particularly beneficial for patients who, in addition to low high-density lipoprotein cholesterol, present with other features of the metabolic syndrome, such as obesity, glucose intolerance, and high triglycerides. Whether other fibrates, niacin, or statins lower coronary heart disease risk in persons with low high-density lipoprotein cholesterol in the absence of high or moderately high low-density lipoprotein cholesterol is unknown. (c)2000 by CHF, Inc.     

Plasma apoprotein and lipoprotein lipid levels in vegetarians.

Low-fat, low-cholesterol, high-P:S-ratio diets greatly affect plasma lipid levels. There is no information as to whether such diets affect only lipoprotein levels or also levels of apoproteins and lipoprotein compositions. It is important to have information on the latter to understand diet-induced changes in the metabolism of lipoproteins. Since vegetarians regularly eat an extremely low-cholesterol, low-fat, and-high-P:S ratio diet, they represent an ideal group to study. Fifty-eight vegetarians who eat no animal products and live on a farm commune were examined. Venous bloods were drawn after 12–14 hr fasts and analyzed for lipoprotein-lipids by Lipid Research Clinic procedures and for apoA-I and apoB by radioimmunoassay. Their normal dietary intake was evaluated with 24-hr food diaries. They averaged 2200 kcal/day with 17% protein, 32% fat, and 51% carbohydrate. Negligible amounts of cholesterol (<10 mg/day) was consumed and the P:S ratio was 1.9. Average lipoprotein-cholesterol levels were depressed to about 60% of age- and sex-specific normal levels compared to a group of normolipemic free-living non-vegetarians of a like age and sex distribution. ApoA-I and apoB values were also decreased, but while LDL-cholesterol:apoB ratios did not change, HDL-cholesterol: apoA-I ratios appeared higher in the vegetarians. HDL-cholesterol:LDL-cholesterol ratios of vegetarians were also elevated. The data suggest that the vegetarian diet depressed VLDL and LDL levels without producing major changes in their compositions, whereas both the levels and compositions of HDL were altered. The changes in LDL levels, in HDL-cholesterol:LDL-cholesterol ratios, and in HDL-cholesterol:apoA-I ratios would each place vegetarians in a lower risk category for the development of clinically manifest atherosclerosis.     

Plasma total homocysteine and cysteine levels as cardiovascular risk factors in coronary heart disease

OBJECTIVES: As an important risk factor for coronary atherosclerosis, elevated plasma total homocysteine (t-hcy) concentration has recently received greater attention than have conventional risk factors. Though less reactive than homocysteine, cysteine (cys) is the most abundant plasma thiol and may function as an extracellular regulating factor of thiol/disulfide exchange in order to maintain an adequate redox status. An increase in the total amount of this compound may be noxious depending on environmental conditions. In the present study, the aim was to investigate changes of plasma total cysteine, homocysteine and other determinants in different types of coronary heart disease. DESIGN AND METHODS: Plasma total homocysteine (t-hcy), cysteine (t-cys), cysteinylglycine (t-cysgly), folic acid, vitamin B(12), lipid parameters, total protein, albumin and creatinine levels were studied in plasma from 68 patients with coronary heart disease and 42 healthy controls. After reduction of disulfide bonds with tri-n-buthylphosphine, plasma total thiols were assayed using high performance liquid chromatography (HPLC) and fluorescence detection following derivatization of sulfhydryl groups with 7-fluoro-benzo-2-oxa-1,3-diazole-4-sulfonate (SBD-F). Other parameters were determined by using commercial kits. RESULTS: Plasma t-hcy and t-cys levels were higher in patients (P<0.0001) than in controls, but t-cysgly was unchanged. Hcy and cys levels were correlated with age in the whole study population (r=0.49, r=0.46, P<0.01). Plasma t-hcy positively correlated with plasma t-cys (r=0.53, P<0.01) and t-cysgly (r=0.49, P<0.01) in patients, and with plasma t-cys (r=0.57, P<0.01) in controls. Postmenopausal women had higher t-cys and t-hcy levels than premenopausal women among the controls (P<0.01). Folate and vitamin B(12) levels were similar in both patients and controls. Patients with vitamin B(12) levels below normal had higher plasma t-cys and t-cysgly levels (P<0.05). Interestingly, control subjects with lower vitamin B(12) levels had lower plasma t-hcy levels (P<0.05). Plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, total protein, albumin and creatinine levels in patients and controls were within the normal range, but only HDL-cholesterol levels in patients were lower than in controls (P<0.0001). Triglyceride and VLDL levels of patients were also higher than those of controls (P<0.0001). CONCLUSIONS: Higher plasma total cysteine levels are as important as higher plasma total homocysteine levels. Both parameters are intercorrelated and may act synergistically. To discern their respective roles in atherosclerotic disease, these aminothiol levels have to be considered together.     

Occupation and risk of nonfatal myocardial infarction.

BACKGROUND--While some analytic studies have suggested that individuals in occupations representing higher compared with lower socioeconomic status have a decreased risk of coronary heart disease, it is unclear whether occupation itself has an etiologic role in the development of coronary heart disease or whether differences in as yet uncontrolled coronary risk factors may account for these differences in risk. METHODS--White-collar vs blue-collar occupation and risk of coronary heart disease was evaluated among 230 male patients hospitalized for a first myocardial infarction and 222 control subjects of the same age, sex, and neighborhood of residence. Information on coronary risk factors was obtained from home interviews, and blood specimens were drawn to test lipid and lipoprotein levels. Usual occupation was dichotomized into white-collar and blue-collar occupation according to the Edwards' classification. RESULTS--The relative risk of myocardial infarction of white-collar compared with blue-collar workers was 0.74 (95% confidence interval, 0.46 to 1.19) after controlling for age, cigarette smoking, family history of premature myocardial infarction, history of treatment for high blood pressure, body mass index, history of diabetes, alcohol consumption, type A personality, leisure-time physical activity, total calories, and percentage of calories consumed as saturated fat. However, there was no residual association after control for high-density lipoprotein cholesterol yielding a relative risk of 0.98 (95% confidence interval, 0.59 to 1.63). CONCLUSIONS--These results suggest that white-collar occupation per se does not appear to protect from coronary heart disease. Any apparent protective effect on myocardial infarction that has been previously observed in white-collar compared with blue-collar workers may be attributable to differences in high-density lipoprotein cholesterol levels.