An epidemiological study was carried out among a random sample of women aged 18 to 69 years to examine possible determinants of plasma high density lipoprotein and total cholesterol (HDL-C and T-C). In a multiple regression analysis consumption of alcohol, fatty fish, and parental longevity showed positive associations with HDL-C, which were statistically significant. Smoking habit, sucrose consumption, and a family history of ischaemic heart disease showed significantly negative associations.
Four classes of etiologic agents that cause human illness have been discovered. Sometimes members of two or more classes of agents cooperate to cause illness. Knowledge of etiology is necessary if a disease is to be eradicated. The leading causes of death in the United States have changed dramatically in the last century. Infection has been replaced by chronic illnesses of obscure etiology. Ischemic heart disease is the leading cause of death in middle age and is the major obstacle to becoming old.
There is clear evidence that populations living in Mediterranean countries enjoy a longer life expectancy than Northern Europeans. Genetic or racial factors do not explain these societal differences as revealed by migrant studies. The major causes of death in affluent societies, cardiovascular disease, cancers and digestive disorders, show markedly different incidence rates in different European countries. These differences seem to depend on the varied dietary patterns in Europe but the classic lipid hypothesis alone fails to explain the differing rates of coronary heart disease.
Dietary changes a hundred years ago in Europe, America and Australia were needed to feed their growing industrial populations. By 1909 margarines were first made by the hydrogenation of marine oils and, later, vegetable oils as a substitute for butter, thereby introducing saturated fats. The demise of the highly nutritious herring and its oil's hydrogenation into margarines seems to have coincided with a big increase in coronary heart disease (CHD).
Changes in lipid metabolism with age result in lower total serum cholesterol and low-density lipoprotein concentrations. There is no evidence that longevity and lipid profiles are influenced by genetic make-up. It is difficult to establish an optimum total serum cholesterol in the elderly but values established in younger subjects give a guide. High-density lipoprotein may be even more protective in the elderly and could turn out to be a better predictor of coronary disease. Screening for the treatment of hypercholesterolaemia should be carried out in the elderly.
Most authorities recommend a prudent diet, moderate exercise, and the maintenance of ideal body weight Although lowering total cholesterol and LDL levels has been demonstrated to lower CHD risk, the results of major clinical trials do not indicate a reduction in overall mortality. CHD is a complicated, multifaceted disease. In addition to recognized risk factors, there may be many more that have yet to be identified. With this in mind, it is important that the nurse does not place unmitigated stress on patients to make radical changes in diet and lifestyle.