Contributions of CVD Epidemiology (part 1): Understanding

What does epidemiology contribute as a major research method and the basic science of prevention, to scientific understanding, to preventive practice, and to the public health?

• CVD epidemiology establishes relationships between personal characteristics and subsequent risk of CVD events, providing causal pathways and predictors of future risk for the individual, thus, the basis for preventive cardiology.
• The risk factors for CVD, confirmed and quantified by epidemiology, have provided a risk paradigm that has successfully guided further research into causes and a base for preventive practice and public policy.
• Relative and absolute risk are quantified, and estimates of population risk attributable to given risk factors guide preventive practice and policy by estimating the potential effect of controlling the risk factors.
• CVD epidemiology has established among industrial societies that the major proportion of cases derives from the central bulk of the risk distribution, that the proportion of people at any arbitrary high risk is directly related to the mean and distribution of the risk factors, that risk is continuous rather than having thresholds, and that the benefit of prevention is proportional to the risk.
• Epidemiology indicates that small changes in great numbers of people profoundly influence population disease rates, that a population strategy is complementary to medical-high risk treatment, and that it is the more efficient preventive approach.
• CVD epidemiology contributes evidence about population differences in disease rates and risk factor distributions and their time trends. This suggests the socio-cultural influences and the eventual potential for CVD prevention among whole populations.
• It provides basic descriptors of the in- and out-of-hospital components of mortality trends, indicating the relative contributions of medical care and of lifestyle and public policy.
• It establishes prospective relationships among population means of CVD risk factors and population risk and disease rates, thus providing estimates of the potential for population-wide prevention.
• Epidemiological studies of pathology confirm the findings about risk factors among the living, and indicate that atherosclerosis begins early in life and that it must be widespread and severe for there to be a major population burden of CVD.
• Epidemiological methods greatly strengthen clinical research and trial design. They provide useful clinical tools for measuring sensitivity, specificity and diagnostic or prognostic power. They enhance the surveillance of risk and disease trends.
• Epidemiology provides clues to disease mechanisms and stimulates new areas of clinical and laboratory science to enrich the whole. Each research strategy is independent and complementary of the other. The broadest understanding of disease phenomena derives from integration of the evidence from all three major research strategies: bench, clinical, and epidemiological. (Henry Blackburn)