The built environment and multimorbidity: a systematic review

Abstract Background Preventing multimorbidity (two or more chronic conditions) is a public health priority. It is unclear if built environment features (human-made buildings and spaces in which people live) are associated with multimorbidity. If they are, modifying the built environment could contribute to prevention strategies. This systematic review aimed to determine whether built environment features are associated with multimorbidity. Methods Four databases were searched (Medline, Embase, SCIE, and SSCI) from inception to November 2024, incorporating terms for multimorbidity and the built environment. Inclusion criteria were: 1) community-based adult populations not selected based on an index condition; 2) a built environment exposure; and 3) outcomes included multimorbidity. Two reviewers independently conducted screening, data extraction, and quality appraisal (using ROBINS-E). A synthesis without meta-analysis was performed. The protocol was registered with PROSPERO (CRD 42024621458). Results Of 5673 records screened, 20 were included. Exposures included air pollution (n = 14), neighbourhood walkability (n = 2), major road proximity (n = 1), housing quality (n = 2), neighbourhood environment (n = 3), food environment (n = 2), and greenness (n = 1). No studies evaluated public transport networks. Multimorbidity definitions varied in terms of the number and types of conditions that contributed. For all studies, the overall risk of bias ranged from high to very high. Preliminary results found consistent positive associations between increasing air pollution concentrations and multimorbidity, and mixed or no associations for other exposures. Key messages • Air pollution may be associated with multimorbidity and could be a target for multimorbidity prevention strategies. • There are widespread knowledge gaps in the association of a range of built environment features (green spaces, transport networks, food environment, walkability) with multimorbidity.