Department of Environmental Health, Harvard T H Chan School of Public Health, 677 Huntington Ave, Boston, MA, 02115, USA.
Environ Health. 2022 Sep 6;21(1):81. doi: 10.1186/s12940-022-00886-4.
Studies examining the association of short-term air pollution exposure and daily deaths have typically been limited to cities and used citywide average exposures, with few using causal models.
To estimate the associations between short-term exposures to fine particulate matter (PM), ozone (O), and nitrogen dioxide (NO) and all-cause and cause-specific mortality in multiple US states using census tract or address exposure and including rural areas, using a double negative control analysis.
We conducted a time-stratified case-crossover study examining the entire population of seven US states from 2000-2015, with over 3 million non-accidental deaths. Daily predictions of PM, O, and NO at 1x1 km grid cells were linked to mortality based on census track or residential address. For each pollutant, we used conditional logistic regression to quantify the association between exposure and the relative risk of mortality conditioning on meteorological variables, other pollutants, and using double negative controls.
A 10 μg/m increase in PM exposure at the moving average of lag 0-2 day was significantly associated with a 0.67% (95%CI: 0.34-1.01%) increase in all-cause mortality. 10 ppb increases in NO or O exposure at lag 0-2 day were marginally associated with and 0.19% (95%CI: -0.01-0.38%) and 0.20 (95% CI-0.01, 0.40), respectively. The adverse effects of PM persisted when pollution levels were restricted to below the current global air pollution standards. Negative control models indicated little likelihood of omitted confounders for PM, and mixed results for the gases. PM was also significantly associated with respiratory mortality and cardiovascular mortality.
Short-term exposure to PM and possibly O and NO are associated with increased risks for all-cause mortality. Our findings delivered evidence that risks of death persisted at levels below currently permissible.
研究短期空气污染暴露与每日死亡人数之间关联的研究通常仅限于城市，并使用全市平均暴露水平，很少使用因果模型。
使用人口普查区或地址暴露数据，并纳入农村地区，使用双重负对照分析，估计美国多个州短期暴露于细颗粒物（PM）、臭氧（O）和二氧化氮（NO）与全因和特定原因死亡率之间的关联。
我们进行了一项时间分层病例交叉研究，研究了 2000 年至 2015 年期间美国七个州的全部人口，超过 300 万人非意外死亡。每天在 1x1 公里的网格单元中预测 PM、O 和 NO，并根据人口普查区或居住地址与死亡率相关联。对于每种污染物，我们使用条件逻辑回归来量化暴露与死亡率之间的关联，条件是气象变量、其他污染物以及使用双重负对照。
滞后 0-2 天移动平均值的 PM 暴露增加 10μg/m 与全因死亡率增加 0.67%（95%CI：0.34-1.01%）显著相关。滞后 0-2 天的 NO 或 O 暴露增加 10ppb 与全因死亡率增加呈边际相关，分别为 0.19%（95%CI：-0.01-0.38%）和 0.20（95%CI：-0.01，0.40）。当污染水平限制在低于当前全球空气污染标准以下时，PM 的不良影响仍然存在。PM 的负对照模型表明，遗漏混杂因素的可能性较小，而对于气体则存在混合结果。PM 还与呼吸死亡和心血管死亡显著相关。
短期暴露于 PM，可能还有 O 和 NO，与全因死亡率增加相关。我们的研究结果提供了证据表明，在目前允许的水平以下，死亡风险仍然存在。
