Assessing the impact of co-created community initiatives on health and equity: a protocol for population-based surveys within the CAIR project in Elche, Spain.

Introduction: The Western health system has primarily focused on a biomedical approach, prioritizing pharmaceutical and clinical treatments while overlooking the social, economic, psychological, and environmental dimensions of health. As a result, biomedical solutions have received disproportionate attention, while non-pharmacological, community-based interventions remain underutilized. The CAIR project seeks to address this imbalance by co-creating community-driven health initiatives in Municipal District 2 of Elche, Spain. This protocol describes the methodology for two population-based surveys conducted before and after the co-creation process to assess changes in key health and wellbeing indicators at the community level. Methods: A community-based participatory process will be implemented to engage residents in co-creating initiatives to promote health and wellbeing over a 3-year period (2026-2028). To evaluate population-level changes related to this co-creation process, a representative survey of 600 adult residents (≥18 years) in Municipal District 2 of Elche (Spain) will be conducted using stratified random sampling, administered both before and after the co-creation process. The survey will assess a set of selected indicators: health-related quality of life, critical health literacy, community capital, social capital and cohesion, and knowledge, attitudes, and practices related to antibiotic use. Sociodemographic data will also be collected to enable equity-focused analyses, including both relative and absolute differences between population groups. Findings from the baseline survey will inform the design and implementation of the co-created initiatives, particularly by highlighting equity considerations across population groups, while a before-after comparisons of survey indicators will be used to explore the effect of the co-created initiatives. Discussion: Overall, this study will generate population-level evidence on the effect of co-created initiatives in a low-income, culturally diverse urban setting in Spain. By documenting the contribution of co-creation to improve key health and wellbeing indicators, it will provide the evidence needed to further advance participatory approaches in public health. Trial registration: https://clinicaltrials.gov/ct2/show/NCT07237971, Research Registry Unique Identifying Number: NCT07237971.