Policies for healthy ageing in response to climate change: Protocol of a systematic review

PLOS One | https://doi.org/10.1371/journal.pone.0323069 April 30, 2025 5 / 8 Second stage screening At this stage, full texts of all potentially eligible documents will be reviewed. Subsequently, 10% of documents deemed eligible will be checked by a second reviewer. Following the PRISMA flowchart [20,22], the various stages of the screening and selection process will be illustrated and reasons for removing some documents will be stated. Data extraction and management Two reviewers will independently extract data from included documents and enter the data into a piloted extraction sheet (please see Appendix 3). Data in the two filled sheets will subsequently be checked by a third reviewer to ensure consistency. Any differences in the two sheets will be discussed and resolved by all reviewers. If the differ- ence is unresolved, the authors of the papers will be contacted, enabling the reviewers to reach an agreement or consensus [23]. If the required data are missing in the article or are not clarified, the authors of the papers will be contacted. Data items The following information will be extracted from each article based on our review objectives: author, publication year, journal name, study design, study setting, type of participants, sample size, country of study, sample demographics (e.g., gender, age, and ethnicity), healthy ageing policies recommended against climate change, healthy ageing policies already adopted against climate change, and policies that discourage the adoption of healthy ageing policies (i.e., counter policies). Risk of bias assessment

The risk of bias and quality of all studies will be assessed with the CASP (Critical Appraisal Skills Programme) or JBI (Joanna Briggs Institute) checklist, depending on which of them is most suited for the studies included [28]. Two review- ers in the team will independently conduct a risk assessment using CASP or JBI, and any disagreements will be resolved through a meeting between the independent reviewers. Data synthesis To identify all healthy ageing policies against climate change, the search strategy utilised in this systematic review is made robust and open. Data synthesis will be based on the review objectives and readers’ potential information needs. Extracted data will, thus, be organised into four categories: (1) bibliographic information of the studies, which will enable readers to identify key attributes of the review; (2) healthy ageing policies adopted; (3) healthy ageing policies recom- mended, (4) groups targeted by the policies, and (5) counter policies. A narrative synthesis [23] will be utilised to organise the studies since the review aims to identify and interpret available policies in their contexts. As part of the synthesis, a table will be created to map all identified policies onto their target groups, contexts (countries), and stage of implementa- tion of adopted policies (i.e., whether the policy is already being implemented or not). Figures will also be used to sum- marise bibliographic information. After organising the studies as discussed above, the final document reporting the outcomes of the review will be

prepared by the reviewers following the PRISMA guideline [22]. Experts in the field of healthy ageing, preferably corre- sponding authors of the papers included, will be invited to review our mapping (table) and confirm if the information in the table reflects the contexts they studied or reported in their papers. In situations where the authors are not available, other