Cardiovascular Disease

are those factors that act directly upon the processes leading to cardiovascular

disease whereas both lifestyle and personal characteristics can lead to

disease by modifying them. There is a lot of evidence suggesting that lifestyles associated with “Western” culture – a diet rich in saturated fats and calories, tobacco smoking and little physical activity – play an important role as causes of the mass occurrence of cardiovascular disease in populations and as risk factors in individuals within populations. This is because these factors can lead to changes in biochemical and physiological characteristics that enhance the development of atherosclerosis and associated thrombotic complications e.g. smoking has an unfavourable effect on plasma lipoproteins, in particular a decrease in HDL. Further, genetic factors can lead to a predisposition or increased susceptibility of individuals, but these are not yet fully understood. In part, this genetic susceptibility appears to be mediated through genetic determinants of biochemical and physiological risk characteristics such as plasma lipids and blood pressure. Adverse lifestyles seem to interact with such genetic influences. Family history of cardiovascular disease is also an important risk factor, but it has not been established whether it is important due to genetic or environmental factors. Further age and sex also seem to act upon biochemical and physiological risk factors. There is evidence for an increased risk of cardiovascular risk with age and there is some evidence pointing towards differences in risk factors between sexes. The most potent risk factor appears to be a personal history of cardiovascular disease as it indicates a susceptibility to the disease as well as the presence of the underlying pathology i.e. blockage of coronary arteries.

There is some evidence pointing towards sex differences in risk factors for cardiovascular disease, but except for hormonal status, no risk factor has been recognised as acting on one gender but not the other. Compelling evidence shows that total cholesterol and low density lipoprotein (LDL) levels, high density cholesterol (HDL) levels, levels of triglycerides as well as diabetes have a greater impact on cardiovascular disease risk in women compared to men. Elevated total cholesterol and LDL levels are major risk factors for cardiovascular disease in both men and women. Levels in both sexes are similar up to about 20 years of age. In the third and fourth decades, cholesterol

levels increase more sharply in men than in women, but they rise or even exceed levels in men following the menopause. The CARE trial, which addressed the effect of pravastatin in patients with elevated cholesterol levels, showed that women had a risk reduction of major coronary events which was twice as large as that in men. Low levels of HDL cholesterol are an important risk factor. They are higher in women than in men from young adulthood onwards. Some studies, but not all, have described a decrease in HDL levels following the menopause. This loss of protection from HDL is considered to be a major factor for the increased cardiovascular risk in postmenopausal women. Although it has been suggested that low levels of HDL are a more important risk factor in men and women, more research needs to be conducted in order to establish this fact. Nevertheless, it appears to show sex differences. A meta-analysis has indicated that elevated triglycerides increase cardiovascular risk more in women than in men, implying a gender difference in the role of triglycerides in atherosclerosis. Diabetes is considered to be a powerful risk factor for cardiovascular disease. Up to 75-80% of adult diabetic patients die of cardiovascular diseases. Compared to diabetic men, who have a two-fold to three-fold increased risk of coronary heart disease, diabetic women are reported to have a three-fold to seven-fold increased risk. Also mortality from myocardial infarction is significantly higher in diabetic women than in nondiabetic women and in men with or without diabetes. In addition, there are indications that risk factors such as smoking, family history and inflammation characterised as C-reactive protein, have a more negative influence on cardiovascular disease risk in women than in men, but this evidence is less compelling and will require further research. On the other hand, the evidence showing that elevated lipoprotein (a) levels as a cardiovascular risk factor seems to be stronger in men than in women. Nevertheless, the results of the studies providing this evidence might have been biased because of the low event rate of cardiovascular disease in women. Thus one can say that there is some evidence of sex differences in the risk factors relating to cardiovascular disease, but some of it is not very good. Therefore it seems that more data are