Aging beyond older adults: Transdisciplinary perspectives on demographic change in Japan

Population aging is increasingly recognized not merely as a demographic phenomenon, but as a broader societal transformation reshaping care systems, labor structures, infrastructure, communication, governance, and everyday social relations. Using Japan as an example of an advanced super-aged society, this paper examines how demographic aging and population shrinking interact with social, technological, institutional, and environmental systems across multiple domains of adaptation. Adopting a transdisciplinary narrative and integrative review approach, the study synthesizes literature spanning sustainability science, gerontology, migration studies, urban planning, linguistics, science and technology studies, and environmental governance. The analysis focuses on four interconnected domains: inclusive infrastructure and linguistic accessibility; technological adaptation and robotic care; caregiving, migration, and labor transformation; and nature-based well-being. The review demonstrates that adaptation in aging societies depends on hybrid systems that combine public welfare institutions, technological interventions, migration pathways, community-based support, and family caregiving. While Japan has advanced barrier-free infrastructure, Universal Design legislation, Yasashii Nihongo initiatives, long-term care systems, and assistive technologies, major tensions persist, including labor shortages, unequal caregiving burdens, technological dependence, and barriers to migrant integration. The findings also show that interventions initially designed for older adults frequently generate co-benefits for migrants, disabled persons, children, caregivers, and local communities. The paper argues that demographic aging cannot be effectively addressed by isolated sectoral or disciplinary responses. Instead, aging societies require integrated and adaptive approaches connecting infrastructure, labor systems, migration, communication, technology, environmental design, and caregiving across multiple stakeholder groups. Japan's experience offers insights for societies undergoing similar demographic transitions.