Hyperlipoproteinemia and coronary heart disease

Serum high density lipoprotein cholesterol and factors influencing its level in healthy Chinese

Serum HDL-cholesterol (HDLc) levels were studied on 2399 healthy urban inhabitants, from newborn to 78 years of age, in Shanghai. The results were as follows. (1) Frequency distribution of serum HDLc levels in most groups was approximately normal after age 20. (2) The serum HDLc levels and HDLc/total cholesterol ratio varied with age and sex among healthy subjects. The mean values of HDLc for people over 30 years of age were 58.7 +/- 11.2 mg/100 ml for males and 62.5 +/- 12.2 mg/100 ml for females. The difference was of statistical significance (P less than 0.01). (3) The mean values of serum HDLc were found to be 40.9 +/- 6.0 mg/100 ml and 40.7 +/- 7.9 mg/100 in male and female neonates respectively. These figures are quite similar to those reported from Western countries and Japan. The serum HDLc level rose steadily with age and such elevation was more marked in females than males before age 30. However, the values became closer at age 60, then began to decrease in both sexes. (4) Serum HDLc levels varied markedly with body weight; they correlated negatively with the weight/height index. (5) No statistically significant relationship was found in Chinese between smoking or drinking and serum HDLc levels. The high level of HDLc seemed a result of environmental factors and is, possibly, related to the lower incidence of coronary heart disease in China.

Pre-entry characteristics of participants in the Lipid Research Clinics' Coronary Primary Prevention Trial

The Coronary Primary Prevention Trial (CPPT), a double-blind, randomized clinical trial being conducted by 12 Lipid Research Clinics in North America, was initiated in 1973 to test whether long-term reduction of plasma total cholesterol in individuals with Type II hyperlipoproteinemia would reduce the incidence of coronary heart disease. The trial is scheduled to conclude in 1983. Here we document that a major requirement of the CPPT--the comparability of the control and experimental groups prior to cholesterol-lowering treatment--has been achieved. The 3810 men participating in the CPPT were allocated to either treatment group at each clinic on the basis of low density lipoprotein cholesterol, S-T segment response to graded exercise testing, and the logistic risk function of age, smoking and diastolic blood pressure. Randomization was performed separately within each of the 96 cells thereby defined. An extensive battery of tests and questionnaires also yielded other laboratory measurements, data on health habits and family history, and sociodemographic information. Mean plasma total cholesterol levels were 291.8 mg/dl for the placebo group, and 291.5 mg/dl for the cholestyramine group. The other lipid and lipoprotein cholesterol levels were very similar in the two treatment groups. Among the 83 variables examined, only five differed significantly (P less than 0.05)--height, weight, albumin, 2-hr-post-challenge glucose, and serum aspartate amino-transferase (AST, SGOT)--and these differences were deemed to be so small as to have little or no clinical importance. Inasmuch as chance alone could produce four statistically different variables, we concluded that it seemed highly likely that the observed differences were attributable to random fluctuation. Thus, we have determined that the randomization process has resulted in two very nearly identical groups.

Participant recruitment to the Coronary Primary Prevention Trial

This report describes participant recruitment to the Coronary Primary Prevention Trial, a long-term multicenter clinical trial sponsored by the National Heart, Lung and Blood Institute to test the effect of lowering plasma cholesterol on the incidence of coronary heart disease. The study protocol limited participation to men 35--59 yr of age with fasting plasma cholesterol of at least 265 mg/dl and in good general health. Recruitment began in July 1973, with a goal of 3550 entries within 18 months using referrals from the medical community as the primary source. The yield from this strategy proved inadequate, necessitating adoption of new recruitment sources which generally involved mass screening. These strategies led to the accrual of 3810 participants, although the pre-entry phase was extended by 19 months, i.e. through July 1976. Overall Trial recruitment experience is presented as well as results obtained from each major recruitment source and center and recommendations for conducting recruitment in future clinical trials.

Coronary insufficiency in children. Coronary arteriographic studies in two siblings from a family with hyperbetalipoproteinemia

A family affected with hyperbetalipoproteinemia was studied. Two siblings, a boy 11 and a girl 9 years of age, with characteristic findings of homozygous type II hyperlipoproteinemia are described. The highly atherogenetic nature of this disorder is illustrated by the occurrence of progressive coronary atheromatosis in the boy, in whom two coronary arteriographic studies documented the development of progressive obstruction of two coronary arteries in the course of 2 years. During this interval angina pectoris developed followed by myocardial infarction, cardiomegaly and congestive heart failure. The sister has remained asymptomatic, with apparently normal coronary arteries at age 9 years. Phonocardiograms were suggestive of aortic valve involvement although no aortic valve gradient was demonstrated by cardiac catheterization.

Coronary artery disease in 116 kindred with familial type II hyperlipoproteinemia

Analysis of cardiovascular status in adult relatives of 116 kindred affected with familial hyperbetalipoproteinemia (type II hyperlipoproteinemia) was carried out to assess coronary artery disease (CAD) risk in relatives with type II (II) compared to unaffected family members. Over 90% of the 738 living relatives were interviewed by one investigator and 12 lead electrocardiograms were obtained. In these, and in 285 deceased relatives, physician and hospital records were utilized to determine CAD events by standard criteria. This study, the largest of its kind, permitted more precise and extensive determination of the CAD risk accompanying severe hyperbetalipoproteinemia than has heretofore been possible. CAD was diagnosed in 29.5% of II's compared with 10.5% of normal relatives (N) ( P < .001). The II's and N's did not differ significantly with regard to age distribution, sex, hypertension, smoking habits, or body mass index. According to the Rose questionnaire, angina pectoris was diagnosed in 21.8% of II's and 6.5% of N's ( P < .001). Documented myocardial infarction occurred in 6% of II's versus 1% of N's ( P = .002). CAD death or myocardial infarction occurred in 10.1% of II's compared with 1.8% of N's ( P < .001). The cumulative probability of nonfatal or fatal CAD by age 40 in male II's was 16% (1 in 6); by age 60, the expectation of an event had risen to 52% (1 in 2). Among male N's, the risk of nonfatal or fatal CAD by age 60 was 12.7%, lagging 20 years behind that seen in male II's. In female II's, the risk of nonfatal or fatal CAD by age 60 was 32.8% compared with only 9.1% in female N's.