ABSTRACT
Science demands evidence, including animal studies, large epidemiological studies with appropriate controls, plausibility, and other information, outlined nicely in a paper by Sir Bradford Hill in 1965. Occupational epidemiology is the scientific study of the effects of workplace exposure on the frequency and distribution of various diseases or injuries in a given population. An epidemiologist studies the occurrence, or incidence or number of new cases over the sum of time individuals in the population were at risk for having that event. The limitations of epidemiology are that epidemiology demonstrates only an association between exposure and a given disease. Cigarette smoking causes lung cancer only when the exposure has been of sufficient duration and intensity. Discussions by experts on various epidemiologic studies of asbestos-exposed workers have often resulted in disagreement on the true magnitude of the exposure-effect relationships for asbestos.
