Epidemiology Health Article

CLINICAL EPIDEMIOLOGY AND EVIDENCE-BASED MEDICINE

In the final quarter of the twentieth century, physicians in clinical practice discovered the value of epidemiologic methods in enhancing the efficacy of treatment regimens, mainly through rigorous attention to the nature and quality of the evidence on which clinical decisions are based. Evidencebased medicine then moved into public health practice, where it is illuminating decisions about many aspects of public health practice, such as the most effective way to deploy public health nurses in a local health department.

OTHER RECENT ADVANCES

Epidemiology made spectacular progress in several other directions in the 1990s. One was in the application of molecular biology, resulting in what is sometimes called molecular epidemiology. Other advances have been made in genetic epidemiology, where the meeting of molecular genetics with public health, occupational and environmental health, and infant and child health has produced both exciting stories of great progress and difficult ethical and moral problems. What are scientists and physicians to do, for instance, with the newfound knowledge and technical capability to identify defective genes, especially genes that, in interaction with some environmental circumstances, can disqualify certain individuals from particular occupations and can render others ineligible for life insurance? Such dilemmas presage a testing time for society's values.

Another set of new challenges face epidemiologists who specialize in studies of risk management. The global environment is changing as the burden of greenhouse gases increases and leads to a rise in average global ambient temperatures, and remote sensing and climate models enable us to predict the likely future distribution of vector-borne diseases such as malaria, dengue, and schistosomiasis. A new realm of risk factor analysis is thus emerging, based on future health scenarios that incorporate climate models and— in the most sophisticated applications—include sets of models for future patterns of biodiversity, human settlements, and economic and industrial dynamics. In these ways epidemiologists are helping to plan the public health services that will be needed in the future.

JOHN M. LAST

(SEE ALSO: Case-Control Study, Cohort Study, Cross-Sectional Study; Epidemiologic Transition; Graunt, John; Hippocrates of Cos; Mortality Rates; Notifiable Diseases; Pott, Percivall; Rates; Rates: Age-Adjusted; Record Linkage; Semmelweiss, Ignaz; Snow, John; Vital Statistics; and other articles on specific diseases mentioned herein)