Linoleic acid content in adipose tissue and coronary heart disease

The possibility of an inverse relation between essential fatty acids in adipose tissue, in particular linoleic acid, and mortality from coronary heart disease was studied by a cross sectional survey of random population samples of apparently healthy men aged 40-49 from four European regions with differing mortality from coronary heart disease. The proportion of linoleic acid in adipose tissue was lowest in men from north Karelia, Finland, where mortality from coronary heart disease is highest, and highest in men from Italy, where mortality is lowest, with intermediate proportions in men from Scotland and south west Finland. Similar gradients were observed for the desaturation and elongation products dihomo-gamma-linolenic and arachidonic acid. The proportion of saturated fatty acids in adipose tissue was highest in Finland, intermediate in Scotland, and lowest in Italy. Italian men also had the highest proportion of oleate in their adipose tissue and the lowest proportion of myristoleate and palmitoleate. Finnish men were more obese and had a higher blood pressure. Serum cholesterol concentration was higher in north Karelia and south west Finland than in Scotland or Italy. High density lipoprotein (HDL) cholesterol concentrations reflected the regional differences in serum cholesterol, being higher in Finland and lower in Italy. The ratios of HDL cholesterol to total cholesterol, however, did not differ. The regional differences in linoleic acid in adipose tissue remained highly significant when the observed differences in other known risk factors for coronary heart disease among the four areas were taken into account by multivariate analysis. The gradients in proportions of polyunsaturated fatty acids probably reflect differences in dietary intake of linoleic acid.     

Predicting coronary heart disease in middle-aged and older persons. The Framington study

Of 1,025 men and 1,445 women, aged 49 to 82 years, who were free of coronary heart disease (CHD), 79 men and 63 women subsequently had CHD. Using a risk function based on cholesterol in the high density and low density lipoproteins, systolic blood pressure, left ventricular hypertrophy, and diabetes, less than 2% of the subsequent CHD cases were found in the lowest decile of risk, whereas 25% of the cases for men and 37% for women were found in the highest decile. Predictability held for each specific age group. This predictability was at least as good as that obtained by the usual CHD risk profile at younger ages.     

Incubation period of coronary heart disease

Serum cholesterol concentrations and blood pressure were measured during 1958-64 among men aged 40-59 who took part in the Seven Countries Study. In the present study these measurements were related to the national mortality from coronary heart disease in the periods 1959-61, 1964-6, 1969-71, and 1974-6. The correlations increased with time (r = +0.86, 0.90, 0.93, and 0.96 respectively for serum cholesterol concentration and r = +0.48, 0.56, 0.57, and 0.64 for systolic blood pressure), suggesting that the "incubation period" between exposure to major coronary risk factors and the maximum effects on mortality may be 10 years or more.     

Total and high density lipoprotein cholesterol in the serum and risk of mortality: evidence of a threshold effect

The association of serum total and high density lipoprotein cholesterol values with 15 year mortality was examined in a cohort of 10 059 Israeli male civil servants and municipal employees aged 40 and above. In 618 of 1664 deaths in the cohort (37%) coronary heart disease was documented as the cause of death. Risk of mortality was analysed by quintiles. Neither total mortality nor coronary heart disease mortality rose with serum cholesterol concentrations up to 5.6 mmol/1 (216 mg/100 ml), representing 60% of the sample. Rates rose appreciably only in the highest quintile (cholesterol concentration greater than 6.2 mmol/1; greater than 241 mg/100 ml). High density lipoprotein cholesterol was similarly, although inversely, associated with total mortality when expressed as a percentage of total cholesterol. The inverse association of high density lipoprotein cholesterol with coronary heart disease mortality was, in contrast, continuous. These data support the hypothesis that over most of the range of cholesterol values coronary mortality risk and total mortality risk are nearly independent of total cholesterol and most probably independent of low density lipoprotein cholesterol values. In multivariate analysis a low concentration of high density lipoprotein cholesterol appeared to be more predictive of mortality than a high concentration of total cholesterol. The latter was very weakly related to mortality from all causes after multivariate adjustment. It is concluded that the findings of this and other major epidemiological studies support the notion of a "threshold effect." Success in reducing mortality through the pharmacological reduction of serum cholesterol in hypercholesterolaemic patients does not warrant a similar approach in people with average or slightly above average values. These findings appear to provide support for a "high risk strategy" in reducing the risk of coronary heart disease.     

Serum cholesterol levels and cancer mortality in 361,662 men screened for the Multiple Risk Factor Intervention Trial

Several prospective studies have demonstrated an association between low serum cholesterol level and subsequent mortality from cancer. This finding was explored in the large cohort (361,662) of men aged 35 to 57 years who were screened for possible randomization to the Multiple Risk Factor Intervention Trial. Mortality follow-up revealed a significant excess of cancer in the lowest decile of serum cholesterol level during the early years of follow-up, which attenuated over time. In contrast, the association between high serum cholesterol and coronary heart disease did not diminish during the average of seven years of follow-up. These findings are consistent with the inference that the association between low serum cholesterol level and cancer is at least in part due to an effect of preclinical cancer on serum cholesterol level. A subset of the cohort (12,866 men) participated in the randomized Multiple Risk Factor Intervention Trial protocol, which called for annual measurements of serum cholesterol level. Among the 150 of these men who died of cancer during the trial, cholesterol level fell 22.7 mg/dL (0.59 mmol/L) more than in the survivors over an equivalent period. These data are consistent with the foregoing inference.     

High density lipoprotein cholesterol is not a major risk factor for ischaemic heart disease in British men

The concentration of high density lipoprotein cholesterol (HDL cholesterol) in serum was measured at initial examination in a large prospective study of men aged 40-59 drawn from general practices in 24 British towns. After an average follow up of 4.2 years 193 cases of major ischaemic heart disease had been registered in 7415 men in whom both HDL cholesterol and total cholesterol values had been measured. The mean HDL cholesterol concentration was lower in the men with ischaemic heart disease ("cases") compared with other men, but the difference became small and non-significant after adjustment for age, body mass index, blood pressure, cigarette smoking, and concentration of non-HDL cholesterol. The higher mean concentration of non-HDL cholesterol in "cases" remained highly significant after adjustment for other factors. Men in the highest fifth of non-HDL cholesterol values had over three times the risk of major ischaemic heart disease compared with men in the lowest fifth. Multivariate analysis showed that non-HDL cholesterol was a more powerful predictor of risk than the HDL to total cholesterol ratio. These British findings were compared with six other prospective studies. All the larger studies showed similar results, suggesting that HDL cholesterol is not a major risk factor in the aetiology of ischaemic heart disease.     

Is elevated serum cholesterol level a risk factor for coronary heart disease in the elderly?

Since serum cholesterol is a major component in the causal pathway of atherosclerosis, a pathological process that usually progresses with age, we have evaluated reported findings of a diminished association between serum cholesterol level and coronary heart disease in the elderly. In the Honolulu (Hawaii) Heart Program, 1480 men aged 65 years and older and free of coronary heart disease were followed up for an average of 12 years. Incidence rates of coronary heart disease increased progressively from the lowest to the highest quartile of serum cholesterol level. The independent role of serum cholesterol level as a predictor of coronary heart disease risk was evaluated with other major risk factors using a Cox multivariate regression model. The upper-lower quartile relative risk for serum cholesterol level was 1.64 (95% confidence interval, 1.14 to 2.36). The relative risk for middle-aged men was also 1.64. The results suggest that serum cholesterol level is an independent predictor of coronary heart disease, even among men older than 65 years. Thus, an elevated serum cholesterol level in the elderly should be regarded, as in middle-aged men, to be an indicator for further evaluation of lipoprotein levels and possible intervention.     

Risk of coronary heart disease in women after menopause

An increase in the incidence of coronary heart disease risk has commonly been reported in postmenopausal women. The study population comprised 263 adult healthy men and 237 women (104 premenopausal and 133 postmenopausal) ranging in age group of 21-70 years who were examined for coronary heart disease risk factors from Nellore district in Andhra Pradesh. Anthropometric measurements, blood pressure and serum lipids were analysed using standard procedures. There were no significant differences for anthropometric variables between postmenopausal and premenopausal women. Postmenopausal women had significantly higher levels of blood pressure, pulse rate, serum total cholesterol, triglycerides, low-density lipoprotein cholesterol and ratios of total cholesterol:high-density lipoprotein cholesterol and low-density lipoprotein cholesterol:high-density lipoprotein cholesterol as atherogenic indices than premenopausal women and the corresponding age group of male counterparts. However, the variation of high-density lipoprotein cholesterol levels between these groups were not statistically significant. The prevalence of hypertension, hypercholesterolaemia, hypertriglyceridaemia and atherogenic indices was significantly greater in postmenopausal women than in premenopausal women. This study confirms a higher prevalence of risk factors for coronary heart disease among women in older age group and suggests that when oestrogen production ceases in menopausal women, the risk of coronary heart disease increases.     

Education level and coronary risk factors in Australians

There is an inverse association between social class ranking and mortality from coronary heart disease in Australia and in some other countries. To explain whether this association is related to differences in risk factors, the relationship between coronary risk factors and the highest level of education completed was explored for a reasonably representative cross-section of the adult Australian population. After adjustment for the effects of age, relative weight and alcohol intake, blood pressure was found to vary inversely with education level in both sexes. In men only plasma cholesterol, triglycerides and high density lipoprotein cholesterol levels showed no significant variation with education level. In women, plasma triglycerides and high density lipoprotein cholesterol levels varied inversely with education level after adjustment. There was less cigarette smoking among more highly educated men but no clear smoking trends among women. The findings broadly confirm the results of similar analyses which used occupation as the measure of social class and have implications for future community education programmes in that present strategies may be inappropriate for less highly-educated members of society.     

A single cholesterol measurement underestimates the risk of coronary heart disease. An empirical example from the Lipid Research Clinics Mortality Follow-up Study

In prospective epidemiologic studies of coronary heart disease, a single measurement of cholesterol is made to assess its relationship to the risk of coronary disease. Statistical theory states that if this measurement is subject to within-individual variability, the strength of the relationship will be underestimated. This is empirically shown for the example of plasma cholesterol. For the Lipid Research Clinics Follow-up Study population (comprising 2170 white men over 30 years of age), the age-adjusted coronary heart disease mortality regression coefficient increases from .453 to .496 if the average of two cholesterol measurements is used instead of a single measurement. Since the correlation between the two repeated cholesterol measurements is .815, an increase in the regression coefficient up to .556 would be expected if the true cholesterol values were available. Thus, epidemiologic studies have substantially underestimated the strength of the relationship between cholesterol levels and the risk of coronary disease by calculating the relationship on the basis of a single cholesterol determination.     

Mortality from coronary heart disease and stroke in relation to degree of glycaemia: the Whitehall study

In the Whitehall study of 18 403 male civil servants aged 40-64 years the 10 year mortality rates from coronary heart disease and stroke showed a non-linear relation to two hour blood glucose values, with a significantly increased risk for glucose intolerant subjects with concentrations above the 95th centile point (5.4-11.0 mmol/l; 96-199 mg/100 ml) and for diabetics (blood glucose greater than or equal to 11.1 mmol/l; greater than or equal to 200 mg/100 ml). Multiple logistic analysis showed that between one half and three quarters of the relative risks for deaths from coronary heart disease and stroke were "unexplained" by between group differences in risk factors such as age, blood pressure, obesity, smoking, cholesterol concentration, and electrocardiographic abnormalities. Within the glucose intolerant and diabetic groups the risk factors most strongly related to subsequent death from coronary heart disease were age and blood pressure, with less consistent relations for smoking, cholesterol concentration, and obesity. This study confirms the importance of hypertension as a cardiovascular risk factor in groups with glucose intolerance and diabetes, and this may have important preventive implications.     

Coronary risk factor prevalence in a high incidence area: results from the Belfast MONICA Project.

Northern Ireland remains at the top of the world mortality league for ischaemic heart disease. The Province is providing a centre for the World Health Organisation's MONICA Project. Registration of coronary heart disease events began in 1983 and the first of three population surveys took place in 1983-4. A total of 2,361 men and women aged 25-64 years was screened. Subjects were shorter and heavier than their fellow citizens in Great Britain. The estimated mean cholesterol levels in the 25-64-year-old population (5.80 mmol/l in males and 5.85 mmol/l in females) were similar to those reported from Great Britain. Although mean systolic blood pressures were lower, mild diastolic hypertension was considerably more common; cigarette smoking levels were similar. The results were consistent with those expected for an area with a high coronary heart disease mortality, with more than 80% of subjects being at increased risk in terms of the three major factors (cigarette smoking, hypertension and raised cholesterol). Public concern about coronary heart disease has grown and recently the Department of Health and Social Services (NI) has launched a 10-year prevention programme which will primarily employ a population approach.     

Plasma lipids and lipoprotein cholesterol concentrations in people with different diets in Britain

Concentrations of total cholesterol and cholesterol in the various lipoprotein fractions were measured in vegans, vegetarians, fish eaters (who did not eat meat), and meat eaters. Total and low density lipoprotein cholesterol concentrations were higher in meat eaters than vegans, with vegetarians and fish eaters having intermediate and similar values. High density lipoprotein cholesterol concentration was highest in the fish eaters but did not differ among the other groups. There were striking trends with age in total and low density lipoprotein cholesterol concentrations, which differed between men and women: women showed a steady increase in concentration with age, whereas concentrations in men did not increase appreciably after the age of 40, which may partly explain sex differences in the prevalence of coronary heart disease. The differences in total cholesterol concentration suggest that the incidence of coronary heart disease may be 24% lower in lifelong British vegetarians and 57% lower in lifelong vegans than in meat eaters.     

长沙地区中老年人冠心病危险因素多元分析

对７５２名中老年干部及知识分子健康体检资料进行多元分析。结果表明：男性的冠心病发生率高于女性；冠心病与收缩压及年龄呈正相关，与血清高密度脂蛋白胆固醇浓度负相关。提示我国中老年人血清总胆固醇水平普遍高于理想水平（＜５．１７ｍｍｏｌ·Ｌ￣（－１）），冠心病的保护因子──高密度脂蛋白胆固醇所起的作用尤为突出。     

Prognostic importance of the white blood cell count for coronary, cancer, and all-cause mortality

The relationship of white blood cell count (WBC) to fatal and nonfatal coronary heart disease (CHD) incidence and all-cause and cancer mortality was assessed in a subset of participants in the Multiple Risk Factor Intervention Trial (MRFIT). For this group of 6,222 middle aged men, total WBC count was found to be strongly and significantly related to risk of CHD, independent of smoking status. Change in WBC count from baseline to the annual examination just prior to the CHD event was found to be a significant and independent predictor of CHD risk. For each decrease in WBC count of 1,000/cu mm the risk for CHD death decreased 14%, controlling for baseline WBC count and other CHD risk factors (smoking, cholesterol level, diastolic blood pressure). The WBC count was strongly related cross-sectionally to cigarette smoking and smoking status as indicated by serum thiocyanate concentration. Smokers on average had a WBC count of 7,750/cu mm compared with 6,080/cu mm for nonsmokers. The WBC count was also significantly associated with cancer death, independent of reported smoking and serum thiocyanate levels.     

Risk factors for coronary heart disease in a self-referred population compared with a general population

Screening programmes for community coronary heart disease risk factors aim to identify persons who are at a high risk of the development of coronary heart disease by screening the population for the prevalence of smoking, obesity, high blood pressure and high blood cholesterol concentrations. The effectiveness of such screening programmes is dependent on a number of factors. The characteristics of individuals who attend such screening programmes voluntarily, and the prevalence of abnormal coronary heart disease risk factors that is detected, give a strong indication of the population reach and the potential benefits of the preventive strategy. In this study, persons who attended a self-referred risk-factor screening programme for coronary heart disease were compared with a random sample of the Australian urban population. A disproportionately high number of older persons and of women presented for the self-referred screening programme while smokers were underrepresented. In general, the risk-factor levels of those in the older age-groups who attended the screening programme were lower than were the corresponding measurements that were found in the random sample; the opposite was true for those in the younger age-groups. These results suggest that coronary heart disease risk-factor screening programmes in the community appeal more to those in the health-conscious older age-groups and to women. For heart disease prevention programmes to be more effective, it will be necessary to design screening programmes to attract more men, those in younger age-groups and smokers.     

血清同型半胱氨酸及传统危险因素与冠心病相关性的临床研究

目的探讨血清同型半胱氨酸(HCY)及传统危险因素(胆固醇TC、甘油三酯TG)与冠心病间的关系。方法检测122例冠心病患者和100例健康人血清中HCY浓度及多项生化指标。结果冠心病组HCY和TG浓度明显高于对照组(P0.05),但彼此间并不存在相关性(P0.05);冠心病组高同型半胱氨酸血症(HHCY)的发病率明显高于对照组(P0.05);不论是冠心病患者还是健康人群,HCY浓度都与年龄存在明显的相关性(P0.05),与性别不相关。结论 HHCY可能是冠心病发生的一个独立危险因素;血清HCY的检测有助于冠心病的诊断;中老年人群应普查HCY浓度,以便更好的预防冠心病的发生。     

Identification and treatment of risk factors for coronary heart disease in general practice: a possible screening model

A screening programme for the identification of risk factors for coronary heart disease in all patients aged 25-55 years in a general practice population was studied. The identification of risk factors included measurement of obesity, blood pressure, hypercholesterolaemia, and urinalysis, together with questions about family history, cigarette smoking, alcohol intake, and lifestyle. The patients with identified risk factors were invited to attend a lifestyle intervention clinic organised by the practice nurses and run by the health visitors, with the help of the local authority dietitian. Of 2646 (62%) patients who attended for screening, 78 (64%) of the 121 shown to have a high cholesterol concentration experienced a drop in cholesterol concentration. The mean fall in cholesterol concentration in the 78 patients who showed a positive response to intervention was 1.1 mmol/l. The study was intended as a possible flexible model for screening for coronary heart disease in general practice that could be complemented rather than replaced by opportunistic screening. The issues of organisation, cost, manpower, nonattendance, and effectiveness in a busy general practice environment are discussed.     

Consumption of olive oil, butter, and vegetable oils and coronary heart disease risk factors. The Research Group ATS-RF2 of the Italian National Research Council

The cross-sectional association between consumption of various fats (eg, butter, olive oil, and vegetable oil) and risk factors for coronary heart disease was analyzed in a sample of 4903 Italian men and women 20 to 59 years of age. The intake of fats was ascertained by an interviewer-administered questionnaire. Increased consumption of butter was associated with significantly higher blood pressure and serum cholesterol and glucose levels for men; in women only the association with glucose reached statistical significance. In both sexes consumption of olive oil and vegetable oil was inversely associated with serum cholesterol and glucose levels and systolic blood pressure. These findings were adjusted for confounding effects of other risk factors for cardiovascular disease. These cross-sectional findings from a large population sample suggest that consumption of butter may detrimentally affect coronary risk factors, while polyunsaturated and monounsaturated fats may be associated with a lower coronary risk profile.     

Impact of treating hyperlipidemia or hypertension to reduce the risk of death from coronary artery disease

OBJECTIVE: To compare the prevalence of modifiable risk factors for cardiovascular disease among hypertensive and nonhypertensive adults and to estimate the effect of treating hyperlipidemia or hypertension to reduce the risk of death from coronary artery disease. METHODS: The authors evaluated a sample of 7814 subjects aged 35-74 years free of clinical cardiovascular disease from the Canadian Heart Health Surveys to estimate the prevalence of cardiovascular risk factors. They identified hyperlipidemic subjects (ratio of total cholesterol to high-density lipoprotein cholesterol [total-C/HDL-C] 6.0 [corrected] or more for men and 5.0 [corrected] or more for women) and hypertensive subjects (systolic or diastolic blood pressure 160/90 mm Hg or greater, or receiving pharmacologic or nonpharmacologic treatment). A life expectancy model was used to estimate the rate of death from coronary artery disease following specific treatments. RESULTS: An elevated total-C/HDL-C ratio was significantly more common among hypertensive than nonhypertensive men aged 35-64 (rate ratio [RR] 1.56 for age 35-54, 1.28 for age 55-64) and among hypertensive than nonhypertensive women of all ages (RR 2.73 for age 35-54, 1.58 for age 55-64, 1.31 for age 65-74). Obesity and a sedentary lifestyle were also more common among hypertensive than among nonhypertensive subjects. According to the model, more deaths from coronary artery disease could be prevented among subjects with treated but uncontrolled hypertension by modifying lipids rather than by further reducing blood pressure for men aged 35-54 (reduction of 50 v. 29 deaths per 100,000) and 55-64 (reduction of 171 v. 104 deaths per 100,000) and for women aged 35-54 (reduction of 44 v. 39 deaths per 100,000). Starting antihypertensive therapy in subjects aged 35-74 with untreated hypertension would achieve a greater net reduction in deaths from coronary artery disease than would lipid lowering. Nonetheless, the benefits of lipid therapy were substantial: lipid intervention among hypertensive subjects aged 35-74 represented 36% of the total benefits of treating hyperlipidemia in the total hyperlipidemic population. INTERPRETATION: The clustering of hyperlipidemia and the potential benefits of treatment among hypertensive adults demonstrate the need for screening and treating other cardiovascular risk factors beyond simply controlling blood pressure.