GUIDELINES FOR APPLICATION OF METAANALYSIS IN ENVIRONMENTAL EPIDEMIOLOGY

The use of meta-analysis in environmental epidemiology can enhance the value of epidemiologic data in debates about environmental health ris ks. Meta-analysis may be particularly useful to formally examine sourc es of heterogeneity, to clarify the relationship between environmental exposures and health effects, and to generate information beyond that provided by individual studies or a narrative review. However, meta-a nalysis may not be useful when the relationship between exposure and d isease is obvious, when there are only a few studies of the key health outcomes, or when there is substantial confounding or other biases wh ich cannot be adjusted for in the analysis. Recent increases in the us e of meta-analysis in environmental epidemiology have highlighted the need for guidelines for the application of the technique, Guidelines, in the form of desirable and undesirable attributes, are presented in this paper for various components of a metaanalysis including study id entification and selection; data extraction and analysis; and interpre tation, presentation, and communication of results, Also discussed are the appropriateness of the use of meta-analysis in environmental heal th studies and when metaanalysis should or should not be used. (C) 199 5 Academic Press, Inc