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 4 / 8 experts but are not legally adopted in the given context. Outcome measures will include a description of groups targeted with the policies (e.g., whether policies are targeted at only older adults or the general population). Search strategy Electronic search Electronic searches will be performed in eight standard databases: Web of Science, SCOPUS, MEDLINE, PsycINFO (accessed via EBSCO Host), Cochrane Library, ProQuest, Google Scholar, and CINAHL Ultimate (accessed via EBSCO Host). Searches will be based on (1) healthy ageing, (2) climate change, and (3) policies. Terms relating to these key- words will be identified by exploring Medical Subject Headings (MeSH) terms at MEDLINE (via PubMed). Identification of MeSH terms will be done by two independent individuals in the review team and any disagreement will be resolved by them through a discussion. A sample of the search strategy generated is shown in Appendix 2. The sensitivity of the search strategy will be examined by assessing whether it retrieves five key articles [23] that were previously identified with Elicit, a digital tool powered by artificial intelligence [24]. Non-electronic search Some relevant articles or documents may not be available online. To identify and include such documents, we will search the printed literature catalogues of the University of Essex Library. This library has information about all its printed doc-

uments (e.g., articles, book chapters, and grey literature) on a digital platform where researchers can search for printed literature. We will perform an electronic search for relevant printed documents on this platform with our search strategy and subsequently request relevant documents found from the library. Document selection All documents found in the eight electronic databases will be exported to EndNote (Thompson Reuters) where duplicate documents will be removed with the EndNote auto-duplication function. Because this function partially removes duplicates [25], we will remove any other duplicates with the hand-searching technique. In this vein, references will be ordered by authors’ first names and titles, allowing for the identification of duplicates skipped earlier. First stage screening Two independent reviewers will initially screen all titles and abstracts after removing duplicates. This process is aimed at separating studies that are potentially eligible from those not eligible. To identify “potentially eligible” studies, the following procedures will be followed: Study participants. For materials to be considered potentially eligible, their titles or abstracts should clearly show that the study participants were individuals of the general population (often people aged 18 years or older). In the literature, 50 years is used as the minimum old age [26], so studies including older adults aged 50 years or older will be potentially eligible. Such materials will be seen as studies focused on older adults.

Intervention. All interventions (e.g., RCT and longitudinal studies), reviews, commentaries, or publicly available material that report relevant healthy ageing policies will be deemed potentially eligible. Titles or abstracts must clarify whether any policy recommendations, acknowledgements, or discussions are in the study. Study characteristics. Potentially eligible studies must be published in English to date. Such studies can be peer- reviewed materials or grey literature (e.g., policy analysis, white papers, and policy briefs). After documents are screened as discussed above, both independent reviewers will meet to identify and resolve any dis- agreements. If a consensus cannot be reached by them, a third reviewer will be invited to help reach a consensus. The inter- rater reliability between the two reviewers will be calculated with Cohen’s kappa statistic to establish a final consensus [27].