Article Text

Original research
Health effects of climate change: an overview of systematic reviews
  1. Rhea J Rocque1,
  2. Caroline Beaudoin2,
  3. Ruth Ndjaboue2,3,
  4. Laura Cameron1,
  5. Louann Poirier-Bergeron2,
  6. Rose-Alice Poulin-Rheault2,
  7. Catherine Fallon2,4,
  8. Andrea C Tricco5,6,
  9. Holly O Witteman2,3
  1. 1Prairie Climate Centre, The University of Winnipeg, Winnipeg, Manitoba, Canada
  2. 2Faculty of Medicine, Université Laval, Quebec, QC, Canada
  3. 3VITAM Research Centre for Sustainable Health, Quebec, QC, Canada
  4. 4CHUQ Research Centre, Quebec, QC, Canada
  5. 5Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada
  6. 6Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
  1. Correspondence to Dr Rhea J Rocque; rhea.rocque{at}


Objectives We aimed to develop a systematic synthesis of systematic reviews of health impacts of climate change, by synthesising studies’ characteristics, climate impacts, health outcomes and key findings.

Design We conducted an overview of systematic reviews of health impacts of climate change. We registered our review in PROSPERO (CRD42019145972). No ethical approval was required since we used secondary data. Additional data are not available.

Data sources On 22 June 2019, we searched Medline, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Cochrane and Web of Science.

Eligibility criteria We included systematic reviews that explored at least one health impact of climate change.

Data extraction and synthesis We organised systematic reviews according to their key characteristics, including geographical regions, year of publication and authors’ affiliations. We mapped the climate effects and health outcomes being studied and synthesised major findings. We used a modified version of A MeaSurement Tool to Assess systematic Reviews-2 (AMSTAR-2) to assess the quality of studies.

Results We included 94 systematic reviews. Most were published after 2015 and approximately one-fifth contained meta-analyses. Reviews synthesised evidence about five categories of climate impacts; the two most common were meteorological and extreme weather events. Reviews covered 10 health outcome categories; the 3 most common were (1) infectious diseases, (2) mortality and (3) respiratory, cardiovascular or neurological outcomes. Most reviews suggested a deleterious impact of climate change on multiple adverse health outcomes, although the majority also called for more research.

Conclusions Most systematic reviews suggest that climate change is associated with worse human health. This study provides a comprehensive higher order summary of research on health impacts of climate change. Study limitations include possible missed relevant reviews, no meta-meta-analyses, and no assessment of overlap. Future research could explore the potential explanations between these associations to propose adaptation and mitigation strategies and could include broader sociopsychological health impacts of climate change.

  • public health
  • social medicine
  • public health

Data availability statement

Data sharing not applicable as no datasets generated and/or analysed for this study. All data relevant to the study are included in the article or uploaded as supplementary information. Additional data are not available.

This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See:

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Data availability statement

Data sharing not applicable as no datasets generated and/or analysed for this study. All data relevant to the study are included in the article or uploaded as supplementary information. Additional data are not available.

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  • Twitter @RutNdjab, @ATricco, @hwitteman

  • Contributors RN, CF, ACT, HOW contributed to the design of the study. CB, RN, LPB, RAPR and HOW contributed to the systematic search of the literature and selection of studies. RR, HOW, LC conducted data analysis and interpretation. RR and HOW drafted the first version of the article with early revision by CB, LC and RN. All authors critically revised the article and approved the final version for submission for publication. RR and HOW had full access to all the data in the study and had final responsibility for the decision to submit for publication.

  • Funding This study was funded by the Canadian Institutes of Health Research (CIHR) FDN-148426. The CIHR had no role in determining the study design, the plans for data collection or analysis, the decision to publish, nor the preparation of this manuscript. ACT is funded by a Tier 2 Canada Research Chair in Knowledge Synthesis. HOW is funded by a Tier 2 Canada Research Chair in Human-Centred Digital Health.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.