Epidemiology The study of the distribution of, and the physical, biological, social, cultural, and behavioral factors that influence, health-related states or events in specified populations. Epidemiology also includes the application of this study to control of health problems (SOURCE: Last, 2001).

Industrial hygiene The science and art devoted to the recognition, evaluation, and control of the environmental factors or stresses arising from or in the workplace that may cause sickness, impaired health and well-being, or significant discomfort and inefficiency among workers or among persons in the community; the profession that anticipates and controls unhealthy conditions of work to prevent illness among employees (SOURCE: Last, 2001).

Occupational medicine The specialized practice of medicine, public health, and ancillary health professions in an occupational setting in order to promote health and prevent occupationally related disease and injury (SOURCE: Last, 2001).

Surveillance The systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health (SOURCE: MMWR, 2001b:2).