Use of epidemiology in medical specialties: an examination by citation analysis

Epidemiologic methods have been applied unevenly among medical specialties. Identifying current uses and areas of potential research helps clarify and define the field. Using citation analysis of published data, the patterns of references to and by the American Journal of Epidemiology were examined for 1974-1982; 17,574 citations to and 15,872 citations by that Journal were classified according to the subject category of the referencing or referenced journal. Internal medicine and public health/epidemiology journals accounted for the largest proportion of all citations, followed by journals of immunology, cancer, microbiology, pediatrics, cardiovascular system, virology, tropical medicine, statistics, and obstetrics/gynecology. Few citations to or by the Journal were found in the allergy, anesthesiology, dermatology, geriatrics, hematology, nephrology, orthopedics, otorhinolaryngology, radiology, rheumatology, and urology journals. Examination of citations between clinical and epidemiologic literature suggests that adequate interchange between clinicians and epidemiologists is occurring. Citation analysis results for the American Journal of Epidemiology were significantly correlated (p less than 0.05) with those from a MEDLINE search on epidemiologic methods used in research in 22 clinical specialties. Despite inherent limitations, citation analysis appears to be a useful tool for examining interactions and trends in epidemiology and for identifying fields which may be ripe for new epidemiologic studies.