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Challenges and recommendations on the conduct of systematic reviews of observational epidemiologic studies in environmental and occupational health

Journal of Exposure Science & Environmental Epidemiology volume 31, pages 21–30 (2021)Cite this article

Abstract

Systematic reviews are powerful tools for drawing causal inference for evidence-based decision-making. Published systematic reviews and meta-analyses of environmental and occupational epidemiology studies have increased dramatically in recent years; however, the quality and utility of published reviews are variable. Most methodologies were adapted from clinical epidemiology and have not been adequately modified to evaluate and integrate evidence from observational epidemiology studies assessing environmental and occupational hazards, especially in evaluating the quality of exposure assessments. Although many reviews conduct a systematic and transparent assessment for the potential for bias, they are often deficient in subsequently integrating across a body of evidence. A cohesive review considers the impact of the direction and magnitude of potential biases on the results, systematically evaluates important scientific issues such as study sensitivity and effect modifiers, identifies how different studies complement each other, and assesses other potential sources of heterogeneity. Given these challenges of conducting informative systematic reviews of observational studies, we provide a series of specific recommendations based on practical examples for cohesive evidence integration to reach an overall conclusion on a body of evidence to better support policy making in public health.

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Fig. 1: Elements of a well-conducted systematic review.

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Acknowledgements

The authors would like to thank the following people for their thoughtful reviews and comments on this manuscript, which have improved it greatly: Tara Hartley, Kathleen MacMahon, Robert Daniels, Kris Thayer, Tom Luben, Craig Steinmaus, Andrew Rooney, Christina Parks, and Abee Boyles.

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Authors and Affiliations

  1. Integrated Laboratory Systems, Morrisville, NC, USA

    Whitney D. Arroyave & Pam Schwingl

  2. Division of the National Toxicology Program, National Institute of Environmental Health Sciences, Research Triangle Park, NC, USA

    Suril S. Mehta, Kyla W. Taylor & Ruth M. Lunn

  3. International Agency for Research on Cancer, World Health Organization, Lyon, France

    Neela Guha & Nadia Vilahur

  4. Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, CA, USA

    Neela Guha

  5. Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC, USA

    Barbara Glenn, Elizabeth G. Radke & Rebecca M. Nachman

  6. World Trade Center Health Program, National Institute for Occupational Safety and Health, Cincinnati, OH, USA

    Tania Carreón

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Arroyave, W.D., Mehta, S.S., Guha, N. et al. Challenges and recommendations on the conduct of systematic reviews of observational epidemiologic studies in environmental and occupational health. J Expo Sci Environ Epidemiol 31, 21–30 (2021). https://doi.org/10.1038/s41370-020-0228-0

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