EPIDEMIOLOGY AND PATTERNS OF DISEASE

Epidemiology is the study of disease in populations. It was initially developed to explain the spread of infectious dis­eases during epidemics and has emerged as a science to study risk factors for multifactorial diseases, such as heart disease and cancer. Epidemiology looks for patterns, such as age, race, dietary habits, lifestyle, or geographic location of persons affected with a particular disorder. In contrast to biomedical researchers, who seek to elucidate the mecha­nisms of disease production, epidemiologists are more concerned with whether something happens than how it happens.¹⁸ For example, the epidemiologist is more con­cerned with whether smoking itself is related to cardiovas­cular disease and whether the risk for heart disease decreases when smoking ceases. On the other hand, the biomedical researcher is more concerned about the causative agent in cigarette smoke and the pathway by which it contributes to heart disease.

Much of our knowledge about disease comes from epi-demiologic studies. Epidemiologic methods are used to de­termine how a disease is spread, how to control it, how to prevent it, and how to eliminate it. Epidemiologic methods also are used to study the natural history of disease, to eval­uate new preventative and treatment strategies, to explore the impact of different patterns of health care delivery, and to predict future health care needs. As such, epidemiologic studies serve as a basis for clinical decision making, allo­cation of health care dollars, and development of policies related to public health issues.