Associations between environmental perception and self-rated health in the city hierarchy of China: Findings from a national cross-sectional survey

Identifying environmental determinants of health and clarifying their variations is crucial for health promotion in different cities by providing tailored intervention strategies. Although the association between perceived urban environment and health (e.g., self-rated health) has been repeatedly explored, most studies have focused on cities of a specific size, and it is still unknown whether either significant environment variables or the magnitude of the association would vary across different-sized cities. This study investigated how perceived urban environment variables significantly associated with individuals' self-rated health varied from small cities to mega cities in China, based on a national survey including 5963 valid respondents. The results showed that the relationship between self-rated health and city size was U-shaped, with respondents in medium and large cities reporting a low-level self-rated health. Perceived greenness, public facilities, housing supply, and medical services were positively and significantly associated with self-rated health, with the odds ratio (OR) of 1.37 (95%CI: 1.29-1.46), 1.27 (95%CI: 1.19-1.35), 1.14 (95%CI: 1.09-1.20), and 1.17 (95%CI: 1.10-1.24), respectively. Furthermore, the magnitude of the association was significantly larger in mega cities. These findings provide useful evidence for promoting public health in cities of different sizes for achieving health equity and indicate that smaller cities and their health-supportive environment need further attention.