Coronary artery disease

A comparison of blacks and whites 6 to 49 years old revealed striking differences between races with respect to the prevalence, of various dyslipoproteinemias and mean plasma lipid levels. Compared with whites, juvenile and adult blacks of both sexes had higher mean levels of highdensity lipoprotein cholesterol (HDL-C), with correspondingly higher prevalences of the hyperHDL and hypoLDL (low-density lipoprotein) phenotypes. In contrast, whites showed a much higher prevalence of type IV hyperlipoproteinemia and higher mean triglyceride levels in most age-sex groups. Although juvenile blacks had higher mean levels of LDL-C than did whites, this race difference was reversed in men, while women showed inconsistent differences between races. Adult black men and juvenile blacks of both sexes had a somewhat higher prevalence of the type IIA phenotype than whites. The distribution of major HDL-C predictors in this population could not account for the difference in prevalence of hyperHDL between races. These findings suggest that health professionals may find differences in plasma lipid and lipoprotein patterns between their black and white patients, but additional research is needed to ascertain the disease risks associated with dyslipoproteinemia among blacks. Circulation 73 (suppl I), I-119, 1986. THE RELATIVE MORTALITY between U. S. blacks and whites from coronary heart disease (CHD) has varied over time, but black men experience much less CHD mortality than one would expect, given the high frequency of certain CHD risk factors such as hypertension among blacks. Most risk factors show either a higher prevalence in blacks as compared with whites, or else no important differences between races. However, these risk factors were identified in white populations and they may not necessarily predict CHD in blacks.1 2 For total serum cholesterol, a major predictor of CHD in whites, blacks and whites show little difference in mean levels.2 The only prospective study of serum cholesterol and CHD incidence in blacks, a study based on small numbers, revealed no association in black women, and a modest association in black men.3 A different picture, however, emerges with regard to lipoprotein cholesterol fractions, where black From the Central Patient Registry and Coordinating Center and Departments of Biostatistics and Epidemiology, University of North Carolina, Chapel Hill, the Lipid Research Clinic, Department of Pediatrics and Medicine, The Johns Hopkins University School of Medicine, Baltimore, the Cincinnati General Hospital, Cincinnati General Research Center, and the University of Texas Health Sciences Center, School of Public Health, Houston. Supported by NHLBI contracts N01-HVI-2156-L, NO1-HVI-2160L, N01-HV2-2914-L, Y01-HV3-0010-L, N01-HV2-2913-L, NOIHVI-2158-L, N01-HVI-2161-L, N01-HV2-2915-L, NO1-HV1-2159L, N01-HV3-2961-L, and N01-HV6-2941-L. Address for correspondence: Basil M. Rifkind, M.D., Chief, Lipid Metabolism-Atherogenesis Branch, National Heart, Lung, and Blood Institute. National Institutes of Health, Bethesda, MD 20892. Vol. 73 (suppl I), January 1986 adults usually have higher mean levels of high-density lipoprotein cholesterol (HDL-C) than do whites, and whites have higher levels of low-density lipoprotein cholesterol (LDL-C) and very low-density lipoprotein cholesterol (VLDL-C).4 5 In contrast, the Framingham Minority Study6 of black adults found lower mean levels of HDL-C and total cholesterol in blacks than in whites. Blacks in Evans County, GA, also had higher and lower levels, respectively, of apolipoproteins A-I and C-II when compared with whites7; a group of patients receiving hemodialysis showed similar differences between races in levels of HDL-C and apolipoproteins,' and these lipoprotein differences were associated with relatively high cardiovascular mortality in the white male patients. Although black children have slightly higher HDL-C levels than do white children,9 10 cord blood measurements of HDL-C in neonates revealed no difference between races.'112 HDL-C and LDL-C show negative and positive associations, respectively, with the risk of CHD in whites, but no prospective studies have examined these associations in blacks. The use of dyslipoproteinemia (DLP) categories offers another approach to lipoprotein comparisons between races. DLP phenotypes draw attention to the extremes rather than the mid range of lipoprotein distributions in populations, and they provide clinically relevant descriptions of lipid and lipoprotein patterns within individuals. Since mean lipid levels are different for blacks and whites, one might expect similar

The Lipid Research Clinics Program Prevalence Study

Family history as an independent risk factor for coronary artery disease

The relation between parental history of myocardial infarction (MI) and risk of coronary artery disease (CAD) was prospectively examined among 45,317 U.S. male health professionals who were free of diagnosed CAD, 40 to 75 years of age in 1986 and followed for 2 years. These men provided details of parental history of MI, including their parents' age at the first event, their personal history of hypertension, hypercholesterolemia and diabetes mellitus, and a detailed dietary assessment completed at baseline. During 72,454 person-years of follow-up, 181 non-fatal MIs were documented, 49 men died from MI or sudden death, and 140 underwent coronary artery surgery or angioplasty. Compared with men without any history of parental MI, those whose mothers or fathers had had an MI at less than 70 years of age had a substantially elevated risk of MI (relative risk = 2.2, 95% confidence interval, 1.2 to 3.8 for maternal history; relative risk = 1.7, 95% confidence interval 1.2 to 2.3 for paternal history). Risk of MI increased with decreasing age at parental MI. Paternal but not maternal history of MI was related to increased risk of coronary artery surgery. These associations were not appreciably altered by controlling for diet or established risk factors, either individually or in multivariate models. These prospective data indicate that a history of MI in either parent is associated with an increased risk of CAD among men.

A prospective study of parental history off myocardial infarction and coronary artery disease in men

The occurrence of coronary heart disease and its main risk factors were assessed among the first degree relatives of 309 men from South and East Finland, including 203 men with fatal or nonfatal myocardial infarction and 106 healthy reference men under age 56 years. The younger the patient at the diagnosis of a first myocardial infarction, the more common was coronary heart disease in his parents and siblings. The risk of having coronary heart disease by age 55 was, respectively, 11.4, 8.3 and 1.3 times greater in the South and 6.7, 3.6 and 1.8 times greater in the East for the brothers of patients than for the brothers of reference subjects depending on whether the diagnosis of myocardial infarction in the patient had first been established before the age of 46 years at age 46 to 50 years or at age 51 to 55 years. Hypertension and hyperlipidemia, but none of the other risk factors studied, were most common among the relatives of the youngest patients and diminished in frequency with advancing age of the patient. Most of the strong familial component in coronary heart disease of early onset thus appears to be mediated by familial hyperlipidemias and hypertension. It is suggested that the risk of premature coronary heart disease in the persons at highest risk could be largely eliminated if information about family history were used to identify such persons at an early stage and if they were treated properly for their correctable risk factors.

Familial occurrence of coronary heart disease: Effect of age at diagnosis☆

The occurrence of main coronary risk factors was assessed in the families of 211 men under age 56 from East Finland. Fifty men were survivors of a recent myocardial infarction, 55 had died of myocardial infarction, 53 suffered from uncomplicated angina, and 53 were healthy reference men. Familial hyperlipidaemia was twice and familial hypertension three times as common in case as in reference families; other risk factors were equally common in both. Familial hypercholesterolaemia was commonest in the families of men with fatal myocardial infarction, and multiple type familial hyperlipidaemia in those of men with angina. Any increase in familial aggregation of coronary heart disease was invariably paralleled by increased aggregation of hyperlipidaemia and hypertension, with the most impressive aggregation of both traits in case families with a maternal history of early coronary death. It is concluded that most of the familial aggregation of coronary heart disease is mediated by familial aggregations of hyperlipidaemia and hypertension.

https://heart.bmj.com/content/heartjnl/42/4/373.full.pdf

E A Nikkilä

Papers

Aggregation of coronary risk factors in families of men with fatal and non-fatal coronary heart disease.