浙江省绿地暴露与2型糖尿病患者死亡率的关系

Association between Exposure to Green Space and Mortality of Type 2 Diabetes Patients in Zhejiang Province

摘要: 目的：过往研究表明，增加绿地暴露会降低慢性病死亡风险，但在不同地区间环境绿地暴露的健康效应可能存在异质性。本研究基于浙江省糖尿病队列数据，探索了环境绿地暴露2型糖尿病死亡率风险之间的关联及潜在的影响路径。方法：基于浙江省疾控中心糖尿病队列，本研究筛选出成人2型糖尿病(Type 2 Diabetes Mellitus, T2DM)患者，通过计算归一化植被指数反应环境绿地暴露；使用Cox比例风险回归模型估计风险比和95%置信区间，以评估绿地暴露与T2DM死亡率之间的关系；使用中介分析探索绿地暴露与T2DM的潜在路径。结果：浙江省内总体绿化程度良好且各区县绿地暴露水平接近，西南部和西北部地区的绿化程度略高于东北地区及东南沿海地区。在本研究纳入的17,406名成年T2DM患者，其中死亡人数为1096名。生存分析结果显示，相较于NDVI第一四分位数，NDVI第二、三、四四分位数中的个体的T2DM的死亡风险分别降低了20%，17%和16%。中介分析结果未发现二氧化氮，PM_2.5以及步行指数介导了绿地暴露与T2DM的关联。结论：本研究结果显示高水平绿地暴露与低风险T2DM死亡相关，在城市化建设过程中通过增加社区中的绿化面积，有助于延缓T2DM发展，降低T2DM的死亡率。

Abstract: Objective: Previous studies have indicated that an increase in exposure to green space is associated with a decreased risk of mortality from chronic diseases. However, health effects of exposure to green space are heterogeneous among diverse regions. Based on diabetes cohort data from Zhejiang Province, this study has explored an association between exposure to green space and type 2 diabetes (T2DM) mortality, and the potential mediators. Methods: Based on the diabetes cohort of Zhejiang Provincial Center for Disease Control and Prevention, our study included adult T2DM patients. Exposure to green space was assessed by calculating the normalized difference vegetation index (NDVI). Cox regression model was used to assess the relationship between green space exposure and T2DM mortality. Mediation effects by air pollutants (PM_2.5, NO₂) and walk score were examined by mediation analysis models. Results: Overall, the level of greenery in Zhejiang Province is good, and green space exposure levels are similar across different districts. The greening degree of southwest and northwest areas was slightly higher than that of Hangzhou, Jiaxing and other northeast areas and southeast coastal areas. Among the 17,406 adult patients with T2DM included in this study, there were 1096 deaths. Survival analysis results showed that individuals exposure to quartile 2 quartile 3 and quartile 4 of NDVI had a 20%, 17%, and 16% lower risk of death from T2DM, respectively, compared with the first quartile of NDVI. Mediation analysis provides no supportive evidence about the mediation effects of PM_2.5, NO₂ and walk score. Conclusion: Our study found a protective role of exposure to green space on T2DM mortality. Therefore, an improvement of green space, may prevent T2DM progression and reduce mortality attributed to T2DM.