Cox Bianca, Gasparrini Antonio, Catry Boudewijn, Fierens Frans, Vangronsveld Jaco, Nawrot Tim S
From the aCentre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium; bDepartment of Social and Environmental Health Research, cDepartment of Medical Statistics, London School of Hygiene & Tropical Medicine (LSHTM), London, United Kingdom; dPublic Health and Surveillance, Scientific Institute of Public Health (WIV-ISP), Brussels, Belgium; eBelgian Interregional Environment Agency, Brussels, Belgium; and fDepartment of Public Health and Primary Care, Leuven University, Leuven, Belgium.
Epidemiology. 2016 Nov;27(6):779-86. doi: 10.1097/EDE.0000000000000545.
Despite insights for humans, short-term associations of air pollution with mortality to our knowledge have never been studied in animals. We investigated the association between ambient air pollution and risk of mortality in dairy cows and assessed effect modification by season.
We collected ozone (O3), particulate matter (PM10), and nitrogen dioxide (NO2) concentrations at the municipality level for 87,108 dairy cow deaths in Belgium from 2006 to 2009. We combined a case-crossover design with time-varying distributed lag models.
We found acute and delayed associations between air pollution and dairy cattle mortality during the warm season. The increase in mortality for a 10 μg/m increase in 2-day (lag 0-1) O3 was 1.2% (95% confidence interval [CI] = 0.3%, 2.1%), and the corresponding estimates for a 10 μg/m increase in same-day (lag 0) PM10 and NO2 were 1.6% (95% CI = 0.0%, 3.1%) and 9.2% (95% CI = 6.3%, 12%), respectively. Compared with the acute increases, the cumulative 26-day (lag 0-25) estimates were considerably larger for O3 (3.0%; 95% CI = 0.2%, 6.0%) and PM10 (3.2%; 95% CI = -0.6%, 7.2%), but not for NO2 (1.4%; 95% CI = -4.9%, 8.2%). In the cold season, we only observed increased mortality risks associated with same-day (lag 0) exposure to NO2 (1.4%; 95% CI = -0.1%, 3.1%) and with 26-day (lag 0-25) exposure to O3 (4.6%; 95% CI = 2.2%, 7.0%).
Our study adds to the epidemiologic findings in humans and reinforces the evidence on the plausibility of causal effects. Furthermore, our results indicate that air pollution associations go beyond short-term mortality displacement. (See video abstract at http://links.lww.com/EDE/B105.).
尽管空气污染与人类死亡率之间的短期关联已有相关见解，但据我们所知，尚未在动物中进行过空气污染与死亡率的短期关联研究。我们调查了环境空气污染与奶牛死亡率之间的关联，并评估了季节对这种关联的影响。
我们收集了2006年至2009年比利时87108头奶牛死亡案例所在市一级的臭氧（O3）、颗粒物（PM10）和二氧化氮（NO2）浓度。我们将病例交叉设计与随时间变化的分布滞后模型相结合。
我们发现温暖季节空气污染与奶牛死亡率之间存在急性和延迟关联。2天（滞后0 - 1）O3浓度每增加10μg/m³，死亡率增加1.2%（95%置信区间[CI] = 0.3%，2.1%），当日（滞后0）PM10和NO2浓度每增加10μg/m³，相应的估计值分别为1.6%（95% CI = 0.0%，3.1%）和9.2%（95% CI = 6.3%，12%）。与急性增加相比，O3（3.0%；95% CI = 0.2%，6.0%）和PM10（3.2%；95% CI = -0.6%，7.2%）的26天（滞后0 - 25）累积估计值要大得多，但NO2（1.4%；95% CI = -4.9%，8.2%）并非如此。在寒冷季节，我们仅观察到当日（滞后0）暴露于NO2（1.4%；95% CI = -0.1%，3.1%）以及26天（滞后0 - 25）暴露于O3（4.6%；95% CI = 2.2%，7.0%）会增加死亡风险。
我们的研究补充了人类流行病学研究结果，并加强了因果效应合理性的证据。此外，我们的结果表明空气污染的关联超出了短期死亡替代效应。（见视频摘要：http://links.lww.com/EDE/B105.）
