Reviews in epidemiology: current lines of research and future prospects.

Cad. Saúde Pública, Rio de Janeiro, 24 Sup 4:S472-S473, 2008 More than 150 years after the pioneering study by John Snow, more than 50 years since the Framingham longitudinal studies, and more than 30 years since the British civil servants cohort (the Whitehall Study), the improvement of methods and the growing output in epidemiology have led to the creation of epidemiological subspecialties like clinical epidemiology, environmental epidemiology, social epidemiology, and nutritional epidemiology. The list of subspecialties is virtually unlimited, since the epidemiological method has proven highly flexible in its dialogue with other scientific fields, as demonstrated by its partnership with genomic research. The volume of research and publications in epidemiology has reached such numerical levels that it becomes impossible even for specialists to read a representative set of studies. More specifically, when the target public consists of professionals working directly in health services, there is a notorious incompatibility between the amount of information produced and the capacity to access and process it in sufficient time to back evidencebased policies and interventions. In the 20th century, the perception of this mismatch between scientific output and its utilization in the populations that need it (the ultimate target for such applied science) fostered the development of systematic reviews and later meta-analyses. First employed in 1904 by Karl Pearson to combine observations from different clinical trials on the efficacy of the typhoid vaccine in British soldiers, these methods proposed the summarization of epidemiological studies pertaining to a specific object within the vast field of epidemiology. The methodological delimitations vis-a-vis the study object, including specificities of exposures/interventions and outcomes/health problems have fostered important advances in knowledge. Despite acknowledgement that systematic reviews and meta-analyses provide a significant source of scientific information, the publishing space devoted to this type of academic output can still be considered limited and incapable of meeting the various demands, especially in the public health area. This international trend is mirrored in the Brazilian academic community. The initiative of publishing this special Supplement of Cadernos de Saúde Pública/Reports in Public Health results from these considerations and coincides with the 7th Brazilian Congress of Epidemiology and 18th IEA World Congress of Epidemiology in September 2008 in Porto Alegre, Rio Grande do Sul State, Brazil. The articles in this Supplement have resulted from a careful selection of papers by the Editorial Board of CSP in recent months. The overall orientation was to attempt to contemplate various relevant themes and approaches to epidemiology in public health. The journal’s goal is to publish an annual supplement dedicated to reviews in epidemiology, summarizing the state-of-the-art in the field and covering its different subspecialties. We hope that this inaugural supplement featuring reviews in epidemiology will reach its main objective, offering CSP readers a set of in-depth and representative articles in the field’s current watersheds. We further hope that the journal’s annual supplements in epidemiology will be consolidated as a tradition in the future, thus contributing to continuous updating for members of the field. Reviews in epidemiology: current lines of research and future prospects EDITORIAL