Statistical and practical problems of cohort study design: occupational hazards in the health care industry.

Many populations are exposed to health hazards, particularly workers in the health care industry. Yet practical reasons make it impossible or unfeasible for investigators to meet the technical requirements of the cohort method. One such experience is detailed of hospital workers who were members of a large health care workers' union. Given the fact of exposure to known or suspected hazards, two strategies are urged: 1) projection of work toward adoption of rules regarding organizational settings that would make cohort investigation practical when necessary, and 2) development of alternate means by which work can be assessed when cohort analysis cannot be realistically conducted.