[Etiologic study of chronic nonspecific bronchopneumopathies in the work environment]

Epidemiological methods may be used to study the causes of respiratory troubles at work, to test the hypothesis that there is a statistically significant relationship between professional risk factors and respiratory disease. The prognostic value of certain indices and the impact of preventative measures may also be assessed. The choice of method, type of enquiry and selection of the population to be studied and the resources to be used depend on the aims of the study. The definitions both of occupational exposure and the disease should be clearly established in the protocol. The questionnaire, which is indispensable in all investigation into respiratory disorder, should be adapted to the specific research project (for contents, lay-out, relevance and order of questions, allowing for distorting factors). The final objective in the application of an epidemiological method to study occupational risk factors is to develop a preventative strategy at each stage, but most importantly at the very first stage to prevent the appearance of respiratory troubles.