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 3 / 8 Objectives The objectives of this proposed systematic review are (1) to describe policies for healthy ageing adopted (category 1) or recommended in the literature (category 2) in response to climate change, and (2) to describe populations or groups targeted with these policies. Methods Review protocol and registration This protocol is registered (number CRD42025641151) with PROSPERO [19], which is an international prospective register of systematic reviews and meta-analyses. It adheres to the protocol version of the Preferred Reporting Items for Systematic Reviews and Mata-Analyses (PRISMA-P) [20]. Appendix 1 shows a sample PRISMA-P. Subsequently, the systematic review will follow the Reporting Items for Systematic Reviews and Mata-Analyses (PRISMA) flow-chart [21,22]. Any protocol amendments carried out later will be reported in the systematic review. Types of studies Peer-reviewed papers and grey literature published in English to date will be included in this review. Although systematic reviews may focus on peer-reviewed articles, we plan to include grey literature (e.g., policy analysis and white papers) because this is more likely to contain information about existing or recommended policies. All types of designs (e.g., experimental, observational, and quasi-experimental designs) and publications (e.g., commentary, policy analysis, narra- tives) will be included. Population and participants

Only studies focused on ageing and discussing healthy ageing policies will be included. The studies or documents will not be restricted to any period or geographical region. Since ageing is a lifelong process that affects everyone, studies on the general population or specific groups that report policies on healthy ageing will be included. Studies or documents will not be included if they do not report policies in response to climate change or global warming. Types of interventions Healthy ageing policies can be recommended, described, or reported in any type of study, intervention, or publication; hence, studies included in this review should employ any research design. Even so, we expect Delphi studies and research utilising data from expert interviews and focus group discussions to be more likely sources of existing or recom- mended policies. Types of comparators Comparators will be existing policies that act as a barrier to the adoption of healthy ageing policies. These comparators are policies discouraging stakeholders to adopt or roll out healthy ageing policies. Types of outcome measures The primary outcome of this review is describing the policies that are being rolled out or have been recommended against climate change and its events to support people to maintain health as they age. We will identify or assess these policies based on whether they are already being rolled out or are merely recom- mended. “Policies being rolled out” are a framework of guidelines backed by law (i.e., legislation) and are currently being

implemented by a community, country, or region. “Policies recommended” are a framework of guidelines proposed by