BackgroundExposure to build environments, especially residential greenness, offers benefits to reduce the development of atherosclerotic cardiovascular diseases (ASCVD). The 10-year ASCVD risk is a useful indicator for long-term ASCVD risk, but the evidence on the association and potential pathway of residential greenness in mitigating its development remains unclear. ObjectivesThis study aimed to investigate the associations between residential greenness and the 10-year predicted ASCVD risks, and potentially mediation effect on this association by air pollution, body mass index (BMI) and physical activity (PA). MethodsThe baseline of the China Multi-Ethnic Cohort (CMEC) study, enrolling 99,556 adults during 2018–2019, was used in this cross-sectional study. The participants' 10-year ASCVD risks were predicted as low-, moderate-, and high-risk groups, based on the six risk factors: age, smoking, hypertension, low-density lipoprotein cholesterol (LDL-C), high high-density lipoprotein cholesterol (HDL-C), and high total cholesterol (TC). The 3-year mean value within the circular buffer of 500 m and 1000 m of Enhanced Vegetation Index (EVI500m and EVI1000m) were used to assess greenness exposure. Multiple logistic regression was used to evaluate the association between residential greenness and the 10-year ASCVD risks. Stratified analyses by sex, age and smoking status were performed to identify susceptible populations. Causal mediation analysis was used to explore the mediation effects of air pollution, BMI and PA. ResultsA total of 75,975 participants were included, of which 17.9 % (n = 13,614) and 5.6 % (n = 4253) had the moderate and high 10-year ASCVD risks, respectively. Compared to the low-risk group, each interquartile increase in EVI500m and EVI1000m reduced the ASCVD risk of the moderate-risk group by 4 % (OR = 0.96 [0.94, 0.98]) and 4 % (OR = 0.96 [0.94, 0.98]), respectively; and reduced the risk of the high-risk group by 8 % (OR = 0.92 [0.90, 0.96]) and 7 % (OR = 0.93 [0.90, 0.97]), respectively. However, the increased greenness did not affect the ASCVD risk of the high-risk group when compared to the moderate-risk group. Effects of residential greenness on the ASCVD risk were stronger in women than in men (p < 0.05), and were not observed in those aged ≥55. PA and BMI partially mediated the association between greenness and the 10-year ASCVD risk. ConclusionsASCVD prevention strategies should be tailored to maximize the effectiveness within the groups with different ASCVD risks, better at early stages when the ASCVD risk is low.