Epidemiologic associations between occupational and environmental exposures and autoimmune disease: report of a meeting to explore current evidence and identify research needs.

To advance understanding of autoimmunity associated with exposure to environmental factors, an "Exploratory Meeting Epidemiology on Occupational and Environmental Factors Associated with Autoimmunity" was organized in Bilthoven, the Netherlands, from May 10-12, 2000. Even if no firm conclusions can be drawn on a role of certain chemicals in the environment and in the work place in causing or exacerbating autoimmune responses and illnesses, many indications of this to occur exist. The aim of the meeting was to determine the optimal methodology for assessment of autoimmunity associated with occupational or environmental exposures in the human population, and to set up interdisciplinary and collaborative epidemiological studies to investigate the association of exposure to silica, hexachlorobenzene, ultraviolet radiation, and other agents with autoimmunity and autoimmune diseases in the human population. These agents were selected as carrying particular suspicion at present. It was concluded that there is a need for experimental studies in laboratory animals and for clinical investigations to improve scientific knowledge about the causes and mechanisms of environmentally-induced autoimmune disorders and their treatment; in addition there is a need for an interdisciplinary approach to epidemiological studies of the environmental and other causes of these disorders in human populations. Specific designs for epidemiological studies in this context, as well as laboratory assays for health outcomes, were reviewed. Several recommendations for the epidemiological approach to evaluating effects of environmental or occupational agents on autoimmunity were made. The prime recommendations are the following: 1) systematic descriptive epidemiological data on autoimmunity and autoimmune disorders are required; 2) the establishment of disease-reporting registries should be encouraged; 3) the development of internationally accepted standard diagnostic criteria for all autoimmune diseases should be encouraged; 4) the social impact of these disorders should be evaluated and estimations of direct and indirect economic costs should also be made; 5) the methods of exposure assessment used in epidemiological studies should be standardized; 6) laboratory methods for measurement of biological responses should be standardized; and 7) the inclusion of indicators of autoimmunity and autoimmune diseases and of relevant environmental exposures in ongoing epidemiological studies should be encouraged. The importance of studying environmental causes of autoimmune diseases and autoimmunity lies in the identification and prevention of risks to the public health, and in improving our knowledge of basic mechanisms of health and disease.