Haikerwal Anjali, Akram Muhammad, Sim Malcolm R, Meyer Mick, Abramson Michael J, Dennekamp Martine
Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Victoria, Australia.
CSIRO, CSIRO Oceans and Atmosphere Flagship, Melbourne, Victoria, Australia.
Respirology. 2016 Jan;21(1):88-94. doi: 10.1111/resp.12613. Epub 2015 Sep 7.
The 2006-2007 wildfire period was one of the most extensive and long lasting fires in Australian history with high levels of fine particulate matter (PM2.5 ). Large populations were exposed to smoke for over 2 months. The study aimed to investigate the association between wildfire-related PM2.5 exposure and emergency department (ED) visits for asthma.
A time-stratified case-crossover design was used to investigate associations between daily average PM2.5 and ED attendances for asthma from December 2006 to January 2007. ED data were obtained from the Victorian Emergency Minimum Dataset. Smoke dispersion during the wildfire event was modelled using a validated chemical transport model. Exposure data (daily average PM2.5 , temperature and relative humidity) were modelled for the study period. Various lag periods were investigated.
There were 2047 ED attendances for asthma during the study period. After adjusting for temperature and relative humidity, an interquartile range increase in PM2.5 levels of 8.6 μg/m(3) was associated with an increase in ED attendances for asthma by 1.96% (95%CI: 0.02, 3.94) on the day of exposure. Lag periods up to 2 days prior did not show any association. A strong association was observed among women 20 years and older (5.08% 95%CI: 1.76, 8.51).
Wildfire-related PM2.5 was associated with increased risk of ED attendance for asthma during the wildfire event. It is important to understand the role of wildfire PM2.5 as a trigger for asthma presentations.
2006 - 2007年的野火期是澳大利亚历史上规模最大、持续时间最长的火灾时期之一，期间空气中细颗粒物（PM2.5）含量很高。大量人群暴露于烟雾中长达两个多月。本研究旨在调查野火相关的PM2.5暴露与因哮喘前往急诊科就诊之间的关联。
采用时间分层病例交叉设计，调查2006年12月至2007年1月期间日均PM2.5与因哮喘前往急诊科就诊之间的关联。急诊科数据来自维多利亚州紧急最低数据集。利用经过验证的化学传输模型对野火事件期间的烟雾扩散进行建模。对研究期间的暴露数据（日均PM2.5、温度和相对湿度）进行建模。研究了不同的滞后时间。
研究期间有2047例因哮喘前往急诊科就诊的病例。在调整温度和相对湿度后，暴露当天PM2.5水平每增加一个四分位间距8.6 μg/m³，因哮喘前往急诊科就诊的人数增加1.96%（95%置信区间：0.02，3.94）。直至暴露前2天的滞后时间均未显示出任何关联。在20岁及以上女性中观察到强烈关联（5.08%，95%置信区间：1.76，8.51）。
野火相关的PM2.5与野火事件期间因哮喘前往急诊科就诊的风险增加有关。了解野火PM2.5作为哮喘发作诱因的作用很重要。
