Smoking patterns in the coloured population of the Cape Peninsula (CRISIC study)

A cross-sectional study of tobacco-smoking habits in a random sample of 976 coloured subjects aged 15-64 years revealed that smoking was common, 57% of men and 41% of women being current smokers and 10.4% of men and 9.6% of women having stopped smoking. Heavy smoking prevailed, indicating by mean daily consumption of 14.2 and 13.1 cigarettes among male and female smokers respectively; only 33.5% of male and 39.6% of female smokers used less than 10 cigarettes per day. Coloured smokers smoked more heavily during the weekend. Both men and women smoked mostly filter cigarettes. Forty-four per cent of male and 49.5% of female smokers stated that they had attempted to stop smoking, mainly for health reasons. More than one-third of the participants had a positive attitude to combating smoking, particularly those with an educational level higher than Standard 7. Former smokers and heavy smokers had a significantly higher prevalence of ischaemic heart disease than the other participants. Smoking was associated with a low body mass index, low high-density lipoprotein cholesterol levels, low socio-economic standing, high alcohol consumption and type A coronary-prone behaviour in men. In 1982 the economically active coloured population of the Cape Peninsula spent an estimated R36.2 million on cigarettes.     

Health actions and disease patterns related to coronary heart disease in the coloured population of the Cape Peninsula

The health-related behaviour of the Cape Peninsula coloured population, which has been shown to have an adverse coronary heart disease (CHD) risk factor profile, is reported. Private medical services were used most often by participants: 54.1% and 51.6% of males and females respectively had made use of these services during the preceding year. Only 17.9% and 21.8% of males and females respectively had attended day hospitals during the year. Blood pressures were measured in 43.8% and 57.1% of male and female participants respectively during the year preceding the study. The results indicated the need for the measurement of blood pressure to determine the true prevalence of hypertension, since patient reporting of the condition was inaccurate. Attempts to give up smoking had been made by 44.4% of male and 47.1% of female smokers. About 75% of the participants were found to have hypercholesterolaemia, yet their knowledge of the prudent diet was poor and few reported appropriate dietary modifications to protect against CHD. Frequent reporting of hypercholesterolaemia, hypertension and constipation by the study population highlights the need for dietary education. Mortality rates (MRs) for CHD and cerebrovascular disease (CVD) for the coloured and the white populations were compared. In all age groups white males had higher MRs for CHD than coloured males, while coloured females older than 34 years had higher rates than their white counterparts. The coloured population had MRs for CVD that were higher than those of whites.     

The relationship between dietary factors and serum cholesterol values in the coloured population of the Cape Peninsula

A cross-sectional study of 976 coloured subjects aged 15-64 years identified a population consuming a typical Western diet. Nutrient intake, determined by the 24-hour dietary recall method, reflected a diet high in fat (37% of total energy intake) and animal protein and a polyunsaturated/saturated fatty acid ratio of 0.85. Only 32.2% of men and 27.5% of women consumed a prudent diet (Keys score less than or equal to 28). The influence of this Western diet on serum total cholesterol (TC) levels was seen to be marked when participants with a high risk of developing coronary heart disease (CHD) were compared with those with a TC level putting them at low risk; the former consumed significantly more saturated fat and had a higher mean Keys score. Multiple linear regression analysis on TC levels of men identified six variables that explained 26.9% of the variation of TC. These were body mass index, age, the inverse of the polyunsaturated fat intake, saturated fat intake, polyunsaturated/saturated fat ratio and cholesterol intake. For women only three variables (age, the inverse of the polyunsaturated/saturated fat ratio, and body mass index) explained 30.2% of the variation of TC. Promotion of the prudent diet to lower TC levels of the coloured population of the Cape Peninsula is an increasingly urgent priority.     

Change in knowledge in a coronary heart disease risk factor intervention study in three communities

We investigated health and diet knowledge as it relates to coronary heart disease (CHD) in three rural areas which participated in a community-oriented CHD risk factor intervention study. Knowledge of risk factors (risk knowledge) was fairly satisfactory at baseline, but diet knowledge was poor. Males, the young, and individuals with a lower level of education had less knowledge. Intervention consisted of a 3-year small mass media programme in one community (low-intensity intervention, LII), additional interpersonal intervention to high-risk individuals in the second (high-intensity intervention, HII), and no intervention in the control community (C). In the cohorts, with the baseline survey and the follow-up study 4 years apart, knowledge improved by 8.1% points in males (7.5% in females) in the HII community and by 7.1% (6.5%) in the LII community, compared to 5.5% (4.8%) in the C community (P less than 0.01). Diet knowledge improved more than risk knowledge, and individuals with lower initial scores benefitted most. Female scored highest. Educational level made a modest positive contribution to knowledge gain, after adjusting for differences in baseline knowledge. High-risk individuals did not have better knowledge at baseline, nor did they gain more from the intervention. We conclude that community intervention over a 4 year period, based on community diagnosis and tailored to the community's needs, can improve health knowledge.     

The contribution of different food groups to the energy, fat and fibre intake of the Coronary Risk Factor Study (CORIS) population

A dietary survey done in 1979 on a randomly selected 15% subsample (454 males and 659 females, 15-64 years old) of the 1979 Coronary Risk Factor Study (CORIS) population showed that this population consumed a typical Western diet. In order to identify specific weaknesses in the dietary habits of the population, additional analyses were performed on the data. Foods consumed by the respondents were grouped into 8 groups and the percentage contribution of each of these food groups to total energy intake, total macronutrients, dietary cholesterol and dietary fibre intake was determined. A reference, an 8.4 MJ diet, calculated according to the prudent diet guidelines, was also analysed as described above. The results showed that the CORIS respondents' dietary intake compared unfavourably with the values of the reference diet. The meat group was the main source of total fat, saturated fat and dietary cholesterol. The fat group was the second most important source of total fat in the diet, while the milk group was the second most important source of saturated fat. The study population preferred refined cereals and had a low fruit and vegetable intake. These results revealed specific shortcomings in the dietary habits of the CORIS population and emphasised the need for changes necessary to meet the requirements for a prudent diet.     

Coronary risk factors in the coloured population of the Cape Peninsula

A cross-sectional study of risk factors for coronary heart disease (CHD) in a random sample of 976 coloured people revealed a population greatly at risk of CHD. The major reversible risk factors--hypercholesterolaemia, hypertension and smoking--were very common, with 56% of the men and 40% of the women smoking, 18% of both men and women being hypertensive and 17% of both sexes being hypercholesterolaemic. At high cut-off points 62,8% of the men and 59,4% of the women had at least one major reversible risk factor. At lower but real levels of risk, over 80% of the population was affected. Other risk factors such as inactivity, overweight, hyperuricaemia, hypertriglyceridaemia and a positive family history of CHD were all common in this population group. A 'protective' high-density lipoprotein cholesterol level of greater than or equal to 20% of the total serum cholesterol level was found in 74,5% of the men and 81,1% of the women. A comparison with available data on other South African population risk profiles shows marked differences. The need for preventive strategies in the coloured population is clear.     

Anthropometric profile of the coloured population of the Cape Peninsula

Study of a sample of 976 randomly selected coloured persons 15-64 years of age living in the Cape Peninsula included measurement of height, weight and mid-arm circumference and calculation of the body mass index (BMI). The mean height of the men was 167.6 cm and that of the women 156 cm. Mean weight, BMI and mid-arm circumference for men were 65.9 kg, 23.4 and 27.5 cm respectively and those for women 65.8 kg, 27.1 and 28.9 cm respectively. The prevalence of underweight for men (BMI less than 20) was 23.6% and for women (BMI less than 19) 9.8%; 17.7% of men were overweight (BMI greater than or equal to 25) and 3.7% obese (BMI greater than or equal to 30), while 35.2% of women were overweight (BMI greater than or equal to 24) and 18.8% obese. Overweight and obesity were more common among the older coloured women than among a group of South African white women of the same age. Obese women in the age group 35-44 years were 4.8 times more likely to be hypertensive than women of normal weight in the same age group (odds ratio; 95% confidence interval 2.2-4). Older women did not show this association. There were too few obese men to analyse in this manner. Many of the obese participants did not see themselves as obese. Only 19.7% of men and 45.2% of women had attempted to lose weight during the year preceding the study, in many cases using methods known to be ineffective. The coloureds of the Cape Peninsula were found to be a population with shorter stature than South African white and American populations. Some young participants of both sexes and some older men were underweight, while among older women there was a high prevalence of overweight and obesity. The findings may suggest previous undernutrition in both sexes, with a marked tendency to current overnutrition in adult females.     

Intrafamilial variability in the clinical expression of familial hypercholesterolemia: importance of risk factor determination for genetic counselling

Kotze MJ, Davis HJ, Bissbort S, Langenhoven E, Brusnicky J, Oosthuizen CJJ. Intrafamilial variability in the clinical expression of familial hypercholesterolemia: importance of risk factor determination for genetic counselling.
Clin Genet 1993: 43: 295–299. © Munksgaard, 1993
A specific mutation in the low-density lipoprotein receptor (LDLR) gene causes familial hypercholesterolemia (FH) in about 60% of Afrikaner FH heterozygotes. Molecular diagnosis of this so-called FH Afrikaner-1 mutation was performed in a family with the disease. One individual did not develop coronary heart disease (CHD) by age 84, despite having the FH Afrikaner-1 mutation, while his son who inherited the same gene, developed CHD before age 50 and had to undergo bypass surgery. All the sibs in the third generation inherited the defective LDLR gene allele. This variation in clinical presentation creates a counselling dilemma. It also raises questions about the effect of diet and life style, and the possibility of other genes either contributing to the severity of the disease, or protecting against high lipid levels in plasma. An investigation of the influence of selected factors on the clinical expression of the FH Afrikaner-1 mutation in this family indicated that it was especially the elevated apolipoprotein (a) levels, in addition to low levels of high density lipoprotein cholesterol and raised triglyceride and apolipoprotein B levels, that were associated with a greater risk of developing CHD. These findings are thus in accordance with the view that the severity of CHD in FH patients is not only determined by the nature of the gene defect, but is also influenced by other risk factors.     

Intake of macronutrients and their relationship with total cholesterol and high-density lipoprotein cholesterol. The Coronary Risk Factor Study, 1979

In a dietary study on a subsample (1,113 males and females, 15-64 years of age) of the Coronary Risk Factor Study (CORIS) population, dietitians used the 24-hour recall method by interview to quantify nutrient intake and energy distribution and to investigate the relationship between dietary variables and blood lipid values. Mean total fat intakes varied from 35% to 37% of daily energy intake for different age groups. Dietary polyunsaturated/saturated fatty acid ratios varied from 0.48 to 0.59. Cholesterol intakes ranged from 243 mg/d to 500 mg/d and when expressed per 4.2 MJ (1,000 kcal) were similar for males and females. The results of this intrapopulation cross-sectional study showed no significant relationship between dietary variables and total serum cholesterol and high-density lipoprotein cholesterol. However, the low percentage of respondents who met the prudent dietary guidelines add dietary risk factors to the already high prevalence of other major risk factors in this population.