Age-Friendly Approach Is Necessary to Prevent Depopulation: Resident Architectural Designers and Constructors' Evaluation of the Age-Friendliness of Japanese Municipalities.

Japan has the world's largest old population ratio; thus, aging is an urgent societal issue. As global trends seem to be following Japan's social changes, there is an emphasis on municipalities becoming more age-friendly. Hence, we examine the age-friendliness of 135 Japanese municipalities, selecting 240 resident architectural designers and constructors to assess their municipalities using the Age-Friendly Cities and Communities Questionnaire (AFCCQ). The findings indicate that Japan lacks "outdoor spaces and buildings". Additionally, the evaluation of "housing", "community support and health services", and "transportation" in populated municipalities in the past five years was found to be significantly higher than that in depopulated ones. Age-friendliness is significantly affected by the AFCCQ total score (hereafter, Score) based on "housing", "social participation", "community support and health services", "transportation", and "financial situation" evaluations. High specificity (0.939) was found when the score was treated as a marker of depopulation; an age-friendly approach is a necessary condition for preventing depopulation. Furthermore, a lack of "communication and information" was observed in municipalities with a higher rate of single-person households aged 65 years and older. Therefore, resident architectural designers' and constructors' assessments, combined with the AFCCQ, will be a powerful tool for evaluating the age-friendliness of municipalities.