Epidemiology

Epidemiology is the study of the occurrence of disease in people, and the application of that information to the control of health problems. Epidemiological studies look at large numbers of people (a population, as opposed to an individual) to study the association between exposure to a substance or event with the occurrence of an identified disease.

Most health regulations today are based on epidemiological studies. It is the most common method of determining the cause of a disease, and is a technique that is easily accepted and easily understood.

There are some complications with epidemiology. It is critical to know about exposure, quantity, and other details in order to produce a good epidemiological study. According to the National Institute of Environmental Health Sciences, this information may not be available because:

• People may not know what they have been exposed to or the amount of their exposure.

• People find it very difficult to recall details of exposures that occurred many years ago.

Also, epidemiology cannot detect small differences in the rates of common diseases. When a very large number of people may be affected by a common disease, relatively small differences cannot be identified by epidemiology.