Recommendations for the conduct of systematic reviews in toxicology and environmental health research (COSTER).

BACKGROUND: There are several standards that offer explicit guidance on good practice in systematic reviews (SRs) for the medical sciences; however, no similarly comprehensive set of recommendations has been published for SRs that focus on human health risks posed by exposure to environmental challenges, chemical or otherwise. OBJECTIVES: To develop an expert, cross-sector consensus view on a key set of recommended practices for the planning and conduct of SRs in the environmental health sciences. METHODS: A draft set of recommendations was derived from two existing standards for SRs in biomedicine and developed in a consensus process, which engaged international participation from government, industry, non-government organisations, and academia. The consensus process consisted of a workshop, follow-up webinars, email discussion and bilateral phone calls. RESULTS: The Conduct of Systematic Reviews in Toxicology and Environmental Health Research (COSTER) recommendations cover 70 SR practices across eight performance domains. Detailed explanations for specific recommendations are made for those identified by the authors as either being novel to SR in general, specific to the environmental health SR context, or potentially controversial to environmental health SR stakeholders. DISCUSSION: COSTER provides a set of recommendations that should facilitate the production of credible, high-value SRs of environmental health evidence, and advance discussion of a number of controversial aspects of conduct of EH SRs. Key recommendations include the management of conflicts of interest, handling of grey literature, and protocol registration and publication. A process for advancing from COSTER's recommendations to developing a formal standard for EH SRs is also indicated.

Implementing systematic review techniques in chemical risk assessment: Challenges, opportunities and recommendations.

Systematic review (SR) is a rigorous, protocol-driven approach designed to minimise error and bias when summarising the body of research evidence relevant to a specific scientific question. Taking as a comparator the use of SR in synthesising research in healthcare, we argue that SR methods could also pave the way for a "step change" in the transparency, objectivity and communication of chemical risk assessments (CRA) in Europe and elsewhere. We suggest that current controversies around the safety of certain chemicals are partly due to limitations in current CRA procedures which have contributed to ambiguity about the health risks posed by these substances. We present an overview of how SR methods can be applied to the assessment of risks from chemicals, and indicate how challenges in adapting SR methods from healthcare research to the CRA context might be overcome. Regarding the latter, we report the outcomes from a workshop exploring how to increase uptake of SR methods, attended by experts representing a wide range of fields related to chemical toxicology, risk analysis and SR. Priorities which were identified include: the conduct of CRA-focused prototype SRs; the development of a recognised standard of reporting and conduct for SRs in toxicology and CRA; and establishing a network to facilitate research, communication and training in SR methods. We see this paper as a milestone in the creation of a research climate that fosters communication between experts in CRA and SR and facilitates wider uptake of SR methods into CRA.