Step 1. Identifying and Obtaining Existing Health Data

• Another Potential Data Source: Epidemiologic Studies

Sometimes an epidemiologic study has previously been done for a community where a site is under investigation. Epidemiologic studies evaluate the occurrence of illness in a population and any factors, such as lifestyle and chemical exposure, that might be associated with the occurrence of the illnesses.

The type of epidemiologic study most helpful to a health assessor evaluating conditions at a site is a scientific study designed to determine a possible association between contact with a specific chemical and the occurrence of a specific illness.

How does a health assessor decide whether an available epidemiologic study should be included in the health outcome data evaluation?

Although an epidemiologic study can provide an important source of information when evaluating health outcomes in a community, the health assessor needs to consider the appropriateness of the study for this use.

When reviewing an epidemiologic study, the health assessor should consider both strengths and weaknesses of the study, such as whether health issues are clearly stated and health questions are answered; whether reasonable evidence is provided for establishing a relationship between chemical exposure (contact with the chemical) and a disease outcome; whether analysis methods, limitations, and uncertainties are addressed; whether up-to-date scientific methods were used in the study; and whether the conclusions and recommendations are supported by the data presented.