Rossouw Je

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.

Relationship between high density lipoprotein subfractions and coronary risk factors in a rural white population.

The relationship of serum high density lipoprotein cholesterol (HDL-C) levels and of the HDL2-C and HDL3-C subfractions to several factors associated with coronary risk was examined in a cross-sectional study, which included 655 men and 731 women ages 20 to 64 years. Participants with coronary heart disease (CHD) had lower levels of HDL-C, HDL2-C, and HDL3-C; however, only HDL-C in women was significant. Maleness, body mass index, triglyceride levels, tobacco use, and carbohydrate intake (in men) were significantly inversely related to total HDL-C, while alcohol intake was significantly positively related to HDL-C. The associations were stronger for HDL2-C than for HDL3-C, except that alcohol intake in men was more strongly related to HDL3-C. The findings of this study suggest that several factors that influence CHD risk do so in part through modifying HDL2-C levels.

Factors associated with high density lipoprotein cholesterol in a population with high high density lipoprotein cholesterol levels.

A cross-sectional study of a random sample of 976 coloureds (mixed race) of the Cape Peninsula, ages 15 to 64 years old, revealed a population with unexpectedly high levels of high density lipoprotein (HDL) cholesterol. The mean level for men was 55.4±16.1 mg/dl (SD) and for women, 60.8±16.0 mg/dl. The ratio of HDL cholesterol to total cholesterol expressed as a percentage was 26.3%±9.5% for men and 28.1%±9.3% for women. The HDL cholesterol levels were apparently lower than those of black and Negro populations, yet higher than those of Caucasian populations. Men with levels of HDL cholesterol above the median reported a personal history and a family history of coronary heart disease less frequently than did men with lower levels, while women with high levels of HDL cholesterol were less likely to have a history of hypertension or diabetes. Stepwise multiple regression analysis of variables significantly associated with HDL cholesterol levels showed that they explained 29.7% and 24.7%, respectively, of the variation In HDL cholesterol In men and women. Those variables Independently associated with HDL cholesterol In both men and women were: serum triglyceride (−), cigarette consumption (−), alcohol, body mass index (−), age, and serum low density lipoprotein cholesterol levels (−). The reasons for the relatively high HDL cholesterol levels In this population are unknown. However, It would seem possible that these levels offer some protection against the high risk factors of smoking, hypertension, and hypercholesterolemla.

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 communitys needs, can improve health knowledge.