Hubei Province Key Laboratory of Occupational Hazard Identification and Control, School of Public Health, Wuhan University of Science and Technology, Wuhan 430065, China.
Wuhan Center for Disease Control and Prevention, Wuhan 430022, China.
Sci Total Environ. 2024 Dec 1;954:176506. doi: 10.1016/j.scitotenv.2024.176506. Epub 2024 Sep 26.
Fine particulate matter (PM) pollution and extreme temperature events (ETEs) are main environmental threats to human health. Elevated stroke mortality has been growingly linked to PM mass exposure, while its relationship with PM constituents was extensively unstudied across the globe. Additionally, no prior assessments have investigated the interactive effects of PM constituents and ETEs on stroke mortality.
Province-wide records of 320,372 stroke deaths collected in eastern China during 2016-2019 were analyzed using an individual-level time-stratified case-crossover design. Daily gridded estimates of PM mass and its major constituents (i.e., black carbon [BC], organic matter [OM], ammonium [NH], sulfate [SO], and nitrate [NO]) were assigned to stroke cases on case days and control days at the residential address. We assessed 12 ETEs defined by multiple combinations of air temperature thresholds (2.5-10th percentiles for cold spell, 90-97.5th percentiles for heat wave) and durations (2-4 days). Conditional logistic regression model was applied to investigate associations of short-term exposure to PM constituents and ETEs with stroke mortality. Odds ratio and its 95% confidence interval (CI) were assessed for an interquartile range (IQR) increase in each PM constituent and on ETEs days compared with non-ETEs days. Additive interactive effects were quantitatively evaluated via relative excess odds due to interaction (REOI), attributable proportion due to interaction (AP), and synergy index (SI).
Elevated overall stroke mortality was significantly related to PM constituents, with the largest odds observed for NO (1.04, 95% CI: 1.03-1.04, IQR = 11.25 μg/m), followed by OM (1.03, 1.03-1.04, IQR = 7.97 μg/m), NH (1.03, 1.02-1.04, IQR = 6.66 μg/m), BC (1.03, 1.02-1.03, IQR = 1.41 μg/m), and SO (1.03, 1.02-1.03, IQR = 6.67 μg/m). Overall, higher risks of stroke mortality were identified in analyses using more rigorous thresholds and lengthened durations of ETEs definitions, ranging from 1.19 (1.17-1.21) to 1.55 (1.51-1.60) for heat wave, and 1.03 (1.02-1.05) to 1.11 (1.08-1.15) for cold spell, respectively. We observed consistent evidence for the synergistic effects of heat wave and PM constituents on both ischemic and hemorrhagic stroke mortality, where compound exposures to heat wave and secondary inorganic aerosols (i.e., NO, SO, and NH) posed greater increases in risk (0.23< REOI <0.81, 0.16< AP <0.39, and 2.63< SI <8.19).
Short-term exposure to both PM constituents and ETEs were associated with heightened stroke mortality, and heat wave may interact synergistically with PM constituents to trigger stroke deaths.
细颗粒物（PM）污染和极端温度事件（ETE）是对人类健康的主要环境威胁。越来越多的研究表明，中风死亡率与 PM 质量暴露有关，而全球范围内对 PM 成分与中风死亡率之间的关系研究甚少。此外，以前没有评估过 PM 成分和 ETE 对中风死亡率的交互影响。
利用中国东部 2016-2019 年期间 320372 例中风死亡的省级记录，采用个体水平时间分层病例交叉设计进行分析。将 PM 质量及其主要成分（即黑碳[BC]、有机物[OM]、铵[NH]、硫酸盐[SO]和硝酸盐[NO]）的每日网格化估计值分配给病例日和对照日在居住地的中风病例。我们评估了由空气温度阈值（寒冷期为 2.5-10 百分位数，热浪为 90-97.5 百分位数）和持续时间（2-4 天）的多种组合定义的 12 个 ETE。应用条件逻辑回归模型研究 PM 成分和 ETE 短期暴露与中风死亡率之间的关系。与非 ETE 日相比，评估每个 PM 成分和 ETE 日的第 125 百分位数（IQR）增加的优势比（OR）及其 95%置信区间（CI）。通过相对超额比值（REOI）、归因比值（AP）和协同指数（SI）定量评估加性交互作用。
总体中风死亡率与 PM 成分显著相关，最大的 OR 观察到与 NO（1.04，95%CI：1.03-1.04，IQR=11.25μg/m），其次是 OM（1.03，1.03-1.04，IQR=7.97μg/m），NH（1.03，1.02-1.04，IQR=6.66μg/m），BC（1.03，1.02-1.03，IQR=1.41μg/m）和 SO（1.03，1.02-1.03，IQR=6.67μg/m）。总体而言，在使用更严格的阈值和延长 ETE 定义持续时间的分析中，发现中风死亡率的风险更高，热浪的范围从 1.19（1.17-1.21）到 1.55（1.51-1.60），寒冷期为 1.03（1.02-1.05）到 1.11（1.08-1.15）。我们观察到热浪和 PM 成分对缺血性和出血性中风死亡率的协同作用的一致证据，其中热浪和二次无机气溶胶（即 NO、SO 和 NH）的复合暴露导致风险增加更大（0.23<REOI<0.81，0.16<AP<0.39，2.63<SI<8.19）。
短期暴露于 PM 成分和 ETE 均与中风死亡率升高有关，热浪可能与 PM 成分协同作用引发中风死亡。
