Epidemiological reference ranges for low-density lipoprotein cholesterol and apolipoprotein B for identification of increased risk of ischaemic heart disease.

Although there is widespread acceptance that total cholesterol (TC) value reference ranges should be based on epidemiological rather than statistical considerations, the epidemiological action limits for low-density lipoprotein cholesterol (LDL-C) are still incomplete and only statistical reference ranges for apolipoprotein B (Apo-B) levels are available. The combined use of epidemiological reference ranges for TC and incomplete or statistical reference ranges for LDL-C and Apo-B is illogical, since these parameters may fall into discordant risk categories that will hamper and complicate the management of hypercholesterolaemia. Based on a study of lipograms obtained from +/- 3,000 inhabitants of two industrialised Transvaal towns, the age-related epidemiological reference ranges for LDL-C and Apo-B were established. A comparison with published observational studies of other populations, in which comparable lipid, lipoprotein and apolipoprotein methodologies were used, reflected the severity of these lipid-related abnormalities in white South Africans, especially after the age of 30 years. In addition, the serum TC values found in this survey were not significantly different from those obtained 10 years ago.

Influence of a habitual high egg intake on serum lipid levels in a rural coloured population.

The effect of a habitual high cholesterol intake on serum cholesterol and other lipid levels against the background of a moderate fat intake was investigated in 30 rural coloured volunteers (16 men, 14 women) working on an egg farm. Protein contributed approximately 11%, fat 31%, carbohydrate 58% (sucrose 21%) of energy intake. Daily cholesterol intake averaged 575 mg. In men, although not in women, cholesterol intake correlated negatively with serum cholesterol and low-density lipoprotein cholesterol levels, indicating that a high consumption of eggs in the study population did not prejudice lipid homeostasis. The population exhibited a high profile of coronary heart disease risk factors.

Effects of graded sucrose additions on taste preference, acceptability, glycemic index, and insulin response to butter beans.

Dried beans, because of their high-fiber content and low-glycemic index, are especially suitable for diabetic diets. Most South African bean recipes contain sucrose, and since a restriction of artificial sweeteners seems desirable, replacing sucrose would be impractical. Hence, we examined the effects of 10, 20, and 30% sucrose additions to cooked dried butter beans on taste preference and acceptability in 29 diabetic patients and 11 control subjects. The effect of sucrose additions on glycemic index and insulin response to butter beans was determined in control subjects. Both diabetic and control subjects preferred beans with sucrose additions (p less than 0.005). Additions of sucrose up to 20% of total carbohydrate had no adverse effects on glycemic index or insulin response of butter beans (p less than 0.05), which indicates that addition of moderate amounts of sucrose to a low glycemic index food may improve palatability without impairing the favorable effect on blood glucose and insulin response.

Analysis of the diets of 12-year-old children in Cape Town.

As very few data are available regarding the nutrient intake of South African children, a dietary survey was conducted among 843 12-year-old children in Cape Town. Trained interviewers used a 24-hour-recall questionnaire developed for this purpose, inserting the quantity and types of foods consumed during different periods of the day on both a weekday and Sunday. The intake of carbohydrate, protein and fat was always greatest for white males and lowest for black males. This difference was emphasized by the high weekday energy intake of white boys (10 577 kJ), in contrast with the low energy intake of the black boys (6 457 kJ). The findings on kilojoule, carbohydrate, protein, fat and fibre content of the diets of these subjects are presented.

The prevalence of ischaemic heart disease in three rural South African communities.

In a population reportedly excessively prone to ischaemic heart disease (IHD) i.e. South African (SA) whites, a 3-community study of 7188 subjects aged 15-64 showed a high prevalence of chest pain by questionnaire (9.5% of males, 7.7% of females) or by ECG findings suggestive of IHD (12.8% males, 6.7% females). In the oldest decile (55-64 years) the prevalence of chest pain and/or ECG findings was 33.4% of males and 26.1% of females. For all ages, 18.4% of males and 13.1% of females were apparently affected. Though females were as likely as males to have a history of chest pain they had fewer ECG findings suggestive of IHD and the history was less likely to have been confirmed by a doctor. The significance of individual findings, assessed by the strength of their associations with symptomatic history and age, appeared to differ between the sexes; though very common, medium S-T depression was not classed as suggestive of IHD in females, while left ventricular hypertrophy was unimpressive in males. Large and medium Q waves, large S-T depression, large and medium T wave inversion were positive in both sexes, but left and right bundle branch block only in males. There was little overlap between a history of chest pain and suggestive ECG findings; however, a previous diagnosis of IHD by the family doctor increased the overlap by up to 6 times.

An anthropometric survey of the nutritional status of black preschool children in the Dias Divisional Council area, May 1981.

The nutritional status of 1468 Black preschool children in a rural Eastern Cape area was assessed anthropometrically in order to provide the Department of Health and Welfare with a critical evaluation of the effectiveness of its subsidized skimmed milk powder scheme for local authorities in combating kwashiorkor, to indicate factors which influence nutritional levels, and perhaps to provide a sound theoretical and empirical foundation for future health strategies. Weight and height for age (using the norms of the National Center for Health Statistics (NCHS], weight for height, and triceps and subscapular skinfold thickness were used as criteria for assessing nutritional status. Stated age and certified age groups were assessed separately. Depending upon the sex and stated/certified age, the percentages of children falling under the third percentile ranged from 11,1% to 37,0% for NCHS norms and from 10,9% to 15,7% for skinfold thicknesses. Together with an urban assessment undertaken in December 1982 the survey may indicate where local problems will occur.

Coronary risk factor screening in three rural communities. The CORIS baseline study.

A three-community study of rural Afrikaans-speaking Whites in the south-western Cape revealed that the major reversible risk factors hypercholesterolaemia, hypertension and smoking, as well as 'minor' factors such as inactivity, obesity, hyperuricaemia, coronary-prone behaviour and the irreversible risk factors of chest pain, ischaemic changes on the ECG and a family history of ischaemic heart disease (IHD), were exceedingly common. Singly or in combination, the major risk factors were present in the great majority of the study population after the age of 44 years. The interaction of high levels of lifestyle-induced risk factors with constitutional predisposition could adequately explain any excess risk of IHD in the Afrikaans-speaking community. The almost universal risk factor prevalence in this study has major implications for any preventive strategy.

[The control of hypertension in 2 communities. An interim evaluation]. / Die bekamping van hipertensie in twee gemeenskappe. 'n Interim-evaluasie.

More than 26% of Whites studied in two rural communities were found to be hypertensive during the 1979 Coronary Risk Factor Study (CORIS). At re-study during registration at the commencement of the hypertension intervention phase, hypertension could be confirmed in 72%. The mean blood pressures had decreased, and the percentages on treatment or with control of hypertension had improved by 43% and 136% respectively, indicating that screening for, and awareness of, hypertension had beneficial results. During the first 8 months of the hypertension intervention phase, 451 hypertensives were registered in the high-intensity intervention (HII) town, and 166 in the low-intensity intervention (LII) town. In both towns decreases in mean blood pressure and increases in treatment and control percentages could be demonstrated. In the HII town 80% of hypertensives were on treatment and 83% were controlled 4 - 8 months after registration, the most impressive results being achieved in the group which began treatment as a result of the intervention. A group with mild hypertension which was treated by non-pharmacological means only also improved, 66% eventually being controlled. The hypertension programme was three times more successful in the HII town, where the results suggest that hypertension in a community can be effectively controlled in the short term, using for the most part locally available health personnel and facilities.

Knowledge, attitudes and practices in relation to obesity and coronary artery disease. Results of a baseline study conducted among white parents and potential parents in the south-western Cape Province.

A baseline survey to determine the existing knowledge, attitudes and customs concerning different aspects of nutrition was conducted among adults in the south-western Cape Province. This was the first phase in a long-term research project launched with a view to developing a nutritional guidance programme in order to combat the high mortality rate attributed to coronary heart disease.

The effect of ascorbic acid on the activity of lipoprotein lipase in the baboon (Papio ursinus).

The intravenous administration of heparin-released lipoprotein lipase (LPL) into the circulatory system of the baboon (Papio ursinus) is described. After a single heparin injection, a peak value of LPL activity appeared in the circulation with 5 minutes. At low doses of heparin (less than 100 units heparin/kg body mass), LPL disappeared from the circulation in an exponential fashion with a half-life of about 20 minutes. An increase in the heparin dose increased the amount of LPL released into the circulation. In baboons which were deficient in ascorbic acid, less LPL was released into the circulation after specific doses of heparin than in animals that were amply supplied with this vitamin (ascorbic acid 16 mg/kg body mass/day). The separation of plasma LOL, released by heparin, on Sephadex G-150, revealed several distinct molecular species of LPL in the eluant from the columns. In vitro studies indicated that ascorbic acid inhibited cardiac LPL strongly, whereas it had little effect on "post-heparin plasma" LPL. 2somolar concentrations of another reducing agent, mercapto-ethanol, slightly stimulated cardiac LPL in baboons.

Ascorbic acid and blood lipid and uric acid levels of students.

Serum lipid and uric acid levels were investigated in two groups of healthy young students. Each member of the control group was given 1 g of citric acid, and each member of the experimental group 4 g of L-ascorbic aicd daily for 4 months. Blood samples were drawn every month and leucocyte ascorbic acid, serum ascorbic acid, cholesterol, free fatty acids, triglycerides and uric acid were determined. The ascorbic acid did not cause dramatic changes in lipid parameters, and no evidence could be found that ascorbic acid raises serum uric acid levels.

The effects of free fatty acid infusion on glucose metabolism in normal and streptozotocin-treated dogs.

By means of a novel technique for direct intravenous infusion of free fatty acids (FFA) into conscious dogs, it was found that the elevation of FFA levels in normal animals leads to a marked increase in insulin release and to a decrease in plasma glucose concentration. Dogs with streptozotocin-induced diabetes were used for FFA infusion in order to test whether peripheral glucose utilisation would be suppressed by FFA in the absence of the usual insulin response. Diabetic dogs receiving a constant infusion of intravenous glucose were given infusions of oleic acid after control periods of 2-3 hours. Constant intravenous infusion of U-14C-glucose into the diabetic dogs indicated that FFA infusion caused an average transient drop of 36,8% in glucose flux. After 1 1/2 hours of FFA infusion the flux returned to the former rates. Because no change in plasma glucose levels was found during FFA infusion our results can be explained only by a drop in hepatic glucose production concomitant with an equal drop in peripheral glucose utilisation.

The effects of vitamine C on lipid metabolism.

Evidence is presented showing that vitamin C had definite effects on lipid metabolism. The stress of captivity on free-living baboons causes a decrease in serum vitamin C levels and an increase in serum cholesterol levels. Increased dietary intake of vitamin C during the initial stages of captivity significantly decreases the serum cholesterol values. Dietary vitamin C stimulates the synthesis of cholesterol from 14C-labelled acetate and mevalonate in baboon liver homogenates and increases the turnover rate of the cholesterol body pool. Vitamin C inhibits baboon cardiac lipoprotein lipase activity.

Effect of ascorbic acid on serum lipid levels and depot cholesterol of the baboon (Papio ursinus).

Twelve young male baboons were kept on a diet low in ascorbic acid for 3 months before the experiment. Six animals then received intravenous injections of ascorbic acid 60 mg/kg body mass every third day, while an isotonic saline solution was administered to 6 control animals. The serum ascorbic acid concentration of the animals treated with ascorbic acid levelled off after 9 days, at about 1,1 mg/100 ml. Ascorbic acid treatment resulted in a significant increase (P smaller than 0,005) in serum cholesterol values during the initial stages of treatment, but these returned to normal when the body pool was replenished with ascorbic acid. Ascorbic acid also brought about a significant lowering in serum triglyceride values (P smaller than 0.05). In an acute experiment ascorbic acid caused a 12,7% increase in serum cholesterol level 2 hours after the intravenous injection of ascorbic acid 60 mg/kg body mass. The blood glucose value and serum triglyceride concentration were not affected. The results prove that ascorbic acid treatment causes mobilisation of cholesterol from body depots into the bloodstream.