Background: Neighborhood built environment may profoundly influence children's physical activity (PA) and body weight. This study systematically reviewed scientific evidence regarding the impact of built environment on PA and obesity among children and adolescents in China.

Methods: A keyword and reference search was conducted in Active Living Research, Cochrane Library, PubMed, and Web of Science. Studies that met all of the following criteria were included in the review: (1) study designs-experimental studies, observational studies, and qualitative studies; (2) study subjects-Chinese children and/or adolescents aged ≤17 years; (3) exposures-neighborhood built environment; (4) outcomes-PA and/or body weight status; (5) article type-peer-reviewed publications; (6) time window of search-from the inception of an electronicbibliographic database to May 31, 2018; (7) country-China; and (8) language-articles written in English.

Results: A total of 20 studies, including 16 cross-sectional studies, 3 longitudinal studies, and 1 descriptive study, met the predetermined selection criteria and were included in the review. A total of 13 studies adopted subjective built environment measures reported by parents and/or children,2 adopted objective measures (e.g., geographical information system, field observations), and 5 adopted both objective and subjective measures. PA behaviors included PA, physical inactivity, sedentary behavior, active/passive commuting from/to school, and park visits. Among the 16 studies that provided some quantitative estimates of the influence of built environment on PA and body weight status, all reported a statistically significant relationship in the expected direction. Availability and accessibility in proximity to greenspaces, parks, recreational facilities, and sidewalks were found to be associated with increased PA levels, reduced sedentary behaviors, and/or active commuting among Chinese childrenand adolescents. In contrast, the absence of bike lanes and living in higher density residential areas were associated with increased likelihood of childhood overweight and obesity.

Conclusion: Neighborhood built environment plays an important role in Chinese children's PA engagement and weight outcomes. Building new exercise facilities and enhancing the accessibility of existing facilities hold the potential to enhance PA engagement among Chinese children and adolescents. In addition, urban designs that incorporate sidewalks, bike lanes, walking paths, less motorized traffic, and lower residential density are likely to promote PA and prevent childhood obesity in China.