BACKGROUND Previous studies with large data have been widely reported that exposure to fine particulate matter (PM2.5) is associated with all-cause mortality; however, most of these studies adopted ecological time-series designs or have included limited study areas or individuals residing in well-monitored urban areas. However, nationwide cohort studies including cause-specific mortalities with different age groups were sparse. Therefore, this study examined the association between PM2.5 and cause-specific mortality in South Korea using the nationwide cohort. METHODS A longitudinal cohort with 187 917 National Health Insurance Service-National Sample Cohort participants aged 50-79 years in enrolment between 2002 and 2019 was used. Annual average PM2.5 was collected from a machine learning-based ensemble model (a test R2 = 0.87) as an exposure. We performed a time-varying Cox regression model to examine the association between long-term PM2.5 exposure and mortality. To reduce the potential estimation bias, we adopted generalized propensity score weighting method. RESULTS The association with long-term PM2.5 (2-year moving average) was prominent in mortalities related to diabetes mellitus [hazard ratio (HR): 1.03 (95% CI: 1.01, 1.06)], circulatory diseases [HR: 1.02 (95% CI: 1.00, 1.03)] and cancer [HR: 1.01 (95% CI: 1.00, 1.02)]. Meanwhile, circulatory-related mortalities were associated with a longer PM2.5 exposure period (1 or 2-year lags), whereas respiratory-related mortalities were associated with current-year PM2.5 exposure. In addition, the association with PM2.5 was more evident in people aged 50-64 years than in people aged 65-79 years, especially in heart failure-related deaths. CONCLUSIONS This study identified the hypothesis that long-term exposure to PM2.5 is associated with mortality, and the association might be different by causes of death. Our result highlights a novel vulnerable population: the middle-aged population with risk factors related to heart failure.

中文翻译：

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长期暴露于 PM2.5 和死亡率：一项国家健康保险队列研究。


背景 先前的大数据研究已广泛报道，暴露于细颗粒物 （PM2.5） 与全因死亡率相关;然而，这些研究中的大多数采用了生态时间序列设计，或者包括了居住在监测良好的城市地区的有限研究区域或个体。然而，包括不同年龄组的死因特异性死亡率的全国性队列研究很少。因此，本研究使用全国队列检查了韩国 PM2.5 与特定原因死亡率之间的关联。方法 使用 187 917 名 2002 年至 2019 年间注册的 50-79 岁国家健康保险局国家样本队列参与者的纵向队列。从基于机器学习的集成模型（测试 R2 = 0.87）中收集年平均 PM2.5 作为暴露。我们执行了时变 Cox 回归模型来检查长期 PM2.5 暴露与死亡率之间的关联。为了减少潜在的估计偏差，我们采用了广义倾向得分加权方法。结果与长期 PM2.5 （2 年移动平均值） 的相关性在与糖尿病 [风险比 （HR）： 1.03 （95% CI： 1.01， 1.06）]、循环系统疾病 [HR： 1.02 （95% CI： 1.00， 1.03）] 和癌症 [HR： 1.01 （95% CI： 1.00， 1.02）] 相关的死亡率中显著。同时，循环相关死亡率与较长的 PM2.5 暴露期相关（1 或 2 年滞后），而呼吸相关死亡率与当年 PM2.5 暴露相关。此外，与 PM2.5 的相关性在 50-64 岁的人群中比在 65-79 岁的人群中更明显，尤其是在心力衰竭相关死亡中。结论 本研究确定了长期暴露于 PM2 的假设。5 与死亡率相关，并且关联可能因死亡原因而异。我们的结果突出了一个新的弱势群体：具有与心力衰竭相关的风险因素的中年人群。