Against the backdrop of global ageing, a growing empirical literature highlights associations between age-friendly environments (AFEs) and older adults' well-being. However, the evidence is difficult to cumulate because AFE measurement is fragmented, characterized by heterogeneous operational approaches and uneven domain coverage. Importantly, this measurement heterogeneity is not merely a methodological limitation; it acts as a structuring force that shapes inference, comparability, and policy learning across studies. This systematic review aims to map how AFEs are operationalized and how they are connected to older adults’ well-being. Following PRISMA, four databases were searched to April 2025; 5305 records were screened, and 58 studies were included. We classified AFE measures as subjective (n = 37), objective (n = 11), and mixed (n = 10) and mapped indicators to the WHO Age-Friendly Cities and Communities (AFCC) domains. Our synthesis reveals that AFE measurement is skewed to physical domains, such as transportation, outdoor spaces and buildings, and health services, with social domains underspecified. Associations are often positive for features such as reliable public transport, proximate everyday services, and opportunities for social participation; however, magnitudes and even directions vary by context and by how AFEs are operationalized. We also observe non-linear patterns (for example, in street connectivity or greenness), and occasional negative associations, particularly in disadvantaged settings where higher service density may signal unmet need rather than support. Some of this heterogeneity likely reflects analytic choices, including denominator selection, buffer size and shape, and the omission of micro-scale features and barriers. We recommend a comprehensive AFE assessment that combines subjective and objective approaches, balances physical and social domains, and improves transparency on validity and cross-cultural equivalence. Emerging tools such as street-view imagery and other fine-scale urban data can help capture micro-spatial features with greater precision. • AFE measurements were mapped across 58 studies under the WHO AFCC framework. • Measurement skews to physical domains; social domains of AFE are thin. • Objective AFE metrics were mainly constructed via spatial, statistical, and field auditing data. • The WHO AFCC framework dominant the development of subjective AFE metrics. • Links between AFE indicators and well-being are often positive but vary by context and methods.
Zou et al. (2026) studied this question.