Associations of the built environment with type 2 diabetes in Asia: a systematic review

OBJECTIVES: Our study aimed to systematically review the literature and synthesise findings on potential associations of built environment characteristics with type 2 diabetes (T2D) in Asia. DESIGN: Systematic review of the literature. DATA SOURCES: Online databases Medline, Embase and Global Health were used to identify peer-reviewed journal articles published from inception to 23 January 2023. ELIGIBILITY CRITERIA: Eligible studies included cohort, cross-sectional and case–control studies that explored associations of built environment characteristics with T2D among adults 18 years and older in Asia. DATA EXTRACTION AND SYNTHESIS: Covidence online was used to remove duplicates and perform title, abstract and full-text screening. Data extraction was carried out by two independent reviewers using the OVID database and data were imported into MS Excel. Out of 5208 identified studies, 28 studies were included in this systematic review. Due to heterogeneity in study design, built environment and outcome definitions, a semiqualitative analysis was conducted, which synthesised results using weighted z-scores. RESULTS: Five broad categories of built environment characteristics were associated with T2D in Asia. These included urban green space, walkability, food environment, availability and accessibility of services such as recreational and healthcare facilities and air pollution. We found very strong evidence of a positive association of particulate matter (PM(2.5), PM(10)), nitrogen dioxide and sulfur dioxide (p<0.001) with T2D risk. CONCLUSION: Several built environment attributes were significantly related to T2D in Asia. When compared with Western countries, very few studies have been conducted in Asia. Further research is, therefore, warranted to establish the importance of the built environment on T2D. Such evidence is essential for public health and planning policies to (re)design neighbourhoods and help improve public health across Asian countries. PROSPERO REGISTRATION NUMBER: CRD42020214852.