Background

Several studies suggest that living in areas of high surrounding greenness may be associated with a lower cardiopulmonary mortality risk. However, associations of greenness with specific causes of death in cancer patients and survivors has not been examined and it is unknown whether this relationship is affected by area levels of fine particulate matter air pollution (PM_2.5). This study evaluated associations between greenness and PM_2.5 on causes of death in a large, U.S.-based cohort of cancer patients and survivors.

Methods

Surveillance, Epidemiology and End Results (SEER) data were used to generate a cohort of 5,529,005 cancer patients and survivors from 2000 to 2016. Census-tract Normalized Difference Vegetation Index (NDVI) during May-October from 2003 to 2016 was population-weighted to act as a county-level greenness measure. County-level PM_2.5 exposure was estimated from annual concentrations averaged from 1999 to 2015. Cox Proportional Hazards models were used to estimate the association between greenness, PM_2.5, and cause-specific mortality while controlling for age, sex, race, and other individual and county level variables.

Findings

An IQR increase in greenness was associated with a decrease in cancer mortality for cancer patients (Hazard ratio of 0.94, 95% CI: 0.93–0.95), but not for cardiopulmonary mortality (0.98, 95% CI: 0.96–1.00). Inversely, an increase in 10 μg/m³ PM_2.5 was associated with increased cardiopulmonary mortality (1.24, 95% CI: 1.19–1.29), but not cancer mortality (0.99, 95% CI: 0.97–1.00). Hazard ratios were robust to inclusion of PM_2.5 in models with greenness and vice versa. Although exposure estimates were constant over most stratifications, greenness seemed to benefit individuals diagnosed with high survivability cancers (0.92, 95% CI: 0.90–0.95) more than those with low survivability cancers (0.98. 95% CI: 0.96–0.99).

Interpretation

Higher levels of greenness are associated with lower cancer mortality in cancer patients. The evidence suggests minimal confounding between greenness and PM_2.5 exposures and risk of mortality.

中文翻译：

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绿色、空气污染和死亡风险：一项美国癌症患者和幸存者队列研究

背景

几项研究表明，生活在周围绿化程度高的地区可能与较低的心肺死亡风险有关。然而，癌症患者和幸存者的绿色与特定死亡原因之间的关联尚未得到检验，并且尚不清楚这种关系是否受到细颗粒物空气污染 (PM _2.5 ) 区域水平的影响。这项研究评估了绿色和 PM _2.5与美国大型癌症患者和幸存者队列中死亡原因之间的关联。

方法

监测、流行病学和最终结果 (SEER) 数据用于生成 2000 年至 2016 年 5,529,005 名癌症患者和幸存者的队列。2003 年至 2016 年 5 月至 10 月期间的人口普查区归一化差异植被指数 (NDVI) 人口加权至作为县级绿化措施。县级 PM _2.5暴露是根据 1999 年至 2015 年的年平均浓度估算的。Cox 比例风险模型用于估算绿色度、PM _2.5和特定原因死亡率之间的关联，同时控制年龄、性别、种族和其他个体和县级变量。

发现

绿色度的 IQR 增加与癌症患者的癌症死亡率降低相关（风险比为 0.94，95% CI：0.93-0.95），但与心肺死亡率无关（0.98，95% CI：0.96-1.00）。相反，增加 10 μg/m ³ PM _2.5与心肺死亡率增加相关（1.24，95% CI：1.19–1.29），但与癌症死亡率无关（0.99，95% CI：0.97–1.00）。风险比对于将 PM _2.5包含在具有绿色的模型中是稳健的，反之亦然。尽管在大多数分层中，暴露估计值是恒定的，但绿色度似乎比诊断为高生存率癌症（0.92，95% CI：0.90-0.95）的个体更有益于低生存率癌症（0.98，95% CI：0.96-0.99）。

解释

较高的绿化程度与癌症患者较低的癌症死亡率有关。证据表明绿度与 PM _2.5暴露和死亡风险之间的混淆极小。