A NOVEL-APPROACH TO DATA-COLLECTION IN A CASE-CONTROL STUDY OF CANCERAND OCCUPATIONAL EXPOSURES

Background. In community and hospital-based case-control studies, the occupational data collected in interviews are usually limited to respo nses to general questions asked of all study subjects. A procedure is described in which more detailed information can be collected in an ef ficient, standardized and systematic way. Methods. A generic work hist ory is initially collected from all subjects using a computer-assisted interview. The work history includes job title, type of business, job activities, materials and chemicals, and tools and equipment used. Af ter responses are entered into the computer by the interviewer, the co mputer searches a synonym file to identify possible job-specific modul es relevant to the reported job. The modules are detailed questionnair es that address specific jobs administered after obtaining the generic work history. The modules are used to ask questions about the work en vironment; sources of exposure; factors affecting the movement of the agent from the source to the subject, such as local exhaust ventilatio n; and individual and job characteristics. After the interview is comp leted, the work history and responses to the modules are sent electron ically to an industrial hygienist who reviews the information using a custom-designed software package. Where ambiguities or contradictions occur in information reported by the respondent, or for jobs for which no module had been developed, the industrial hygienist generates up t o 10 additional questions per job. These questions are sent back to th e interviewer for administration of a short, second interview. Conclus ions. These procedures, which are being successfully implemented in an on-going case-control study of brain tumours, should improve disease risk estimates over those derived from more traditional approaches to exposure assessment.