The main manifestations of cardiovascular disease (CVD) are coronary heart disease (CHD), cerebrovascular disease (stroke) and peripheral vascular disease, and the underlying cause of these is most often atherosclerosis (see Chapter 37). Numerous factors or conditions are known to increase (or decrease) the probability that atherosclerosis will develop, and the presence in an individual of these cardiovascular risk factors can be used to assess the likelihood that overt cardiovascular morbidity and death will occur in the medium term. Table 34.1 presents an abbreviated summary of the impact of major risk factors on CHD as determined by the Framingham Heart Study.
Table 34.1 Major modifiable risk factors: effects on the risk of coronary heart disease in men and women aged 35–64 years.
| Risk factors | Age-adjusted relative risk* | |
| Men | Women | |
| Cholesterol >240 mg/dL | 1.9 | 1.8 |
| Hypertension >140/90 mmHg | 2.0 | 2.2 |
| Diabetes | 1.5 | 3.7 |
| Left ventricular hypertrophy | 3.0 | 4.6 |
| Smoking | 1.5 | 1.1 |
* Indicates relative risk for individuals with a given factor compared with those without it.
Some risk factors such as age, male sex and family history of CVD are fixed. However, others, including dyslipidaemias, smoking, hypertension, diabetes mellitus, obesity and physical inactivity, are modifiable. These probably account for over 90% of the risk of developing atherosclerotic CVD. The attempt to prevent CVD by targeting modifiable risk factors has become a cornerstone of modern disease management because the occurrence of overt CVD is preceded by the development of subclinical atherosclerosis which takes many years to progress.
Figure 34 illustrates the main mechanisms by which major risk factors are thought to promote the development of atherosclerosis and its most important consequence, CHD. Additional aspects of dyslipidaemias and hypertension are described in Chapters 36–39.
Modifiable Risk Factors
Dyslipidaemias are a heterogeneous group of conditions characterized by abnormal levels of one or more lipoproteins. Lipoproteins are blood-borne particles that contain cholesterol and other lipids. They function to transfer lipids between the intestines, liver and other organs (see Chapter 36).
Dyslipidaemias involving excessive plasma concentrations of low-density lipoprotein (LDL)
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