Background: Age–friendly communities (AFCs) aim to create inclusive societies for older people. Despite the World Health Organization (WHO)'s emphasis on incorporating dementiafriendliness across all phases, including planning, implementation, monitoring, evaluation, and scale-up, there are very few community–level indicators that incorporate dementia–friendly elements. Objective: To develop a community–level AFC indicator based on WHO AFC guidelines incorporating dementia–friendly elements, and examine its validity and reliability. Design: A repeated cross–sectional study using data from the 2016 and 2019 waves of the Japan Gerontological Evaluation Study. Setting and Subjects: Data were collected from 61 school districts in 16 Japanese municipalities, involving 45,162 individuals aged ≥65 years in 2016, and 39,313 in 2019. The 2016 and 2019 datasets were the development and retest samples, respectively. Methods: After identifying 23 candidate items according to the WHO AFC guidelines and expert reviews, data were aggregated by school district. Exploratory factor analysis on the 2016 data helped derive factor structure, confirming reproducibility with the 2019 data. Internal consistency and test–retest reliability were evaluated. Results: The final 17–item indicator comprised three subscales: Social inclusion and dementia–friendliness (7 items, α = 0.86), Social engagement and communication (5 items, α = 0.78), and Age–friendly physical environment (5 items, α = 0.82). The structure showed adequate test–retest reliability (r = 0.71,0.79; ICC = 0.67,0.78). Conclusions: A valid and reliable 17–item community–level indicator was developed, which aligns with the WHO framework and also incorporates dementia–friendly elements. This indicator is useful for monitoring and evaluating to promote the AFC and dementia–friendly communities.

The authors have declared no competing interest.

This study used data from JAGES (the Japan Gerontological Evaluation Study). This study was supported by Grant-in-Aid for Scientific Research (20H00557, 20K10540, 21H03153, 21H03196, 21K17302, 21K11108, 21H00792, 22H00934, 22H03299, 22K04450, 22K13558, 22K17409, 23H00449, 23H03117), Health Labour Sciences Research Grants (19FA1012, 19FA2001, 21FA1012, 22FA2001, 22FA1010, 22FG2001), Research Institute of Science and Technology for Society (JPMJOP1831, JPMJRX21K6) from the Japan Science and Technology (JST), a grant from Japan Health Promotion & Fitness Foundation, TMDU priority research areas grant and National Research Institute for Earth Science and Disaster Resilience. The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the respective funding organizations.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethical Committee of Chiba University (approval no. M10460)

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The data underlying this study are from the JAGES and contain sensitive information. Data for research purposes is available upon request. Requests for the JAGES data can be made to dataadmin.ml@jages.net.