Thunderstorm outflows preceding epidemics of asthma during spring and summer
Thunderstorm outflows preceding epidemics of asthma during spring and summer
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DOI：
10.1136/thorax.56.6.468
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发表时间：
2001-06-01
期刊：
影响因子：
10
通讯作者：
Car, NG
中科院分区：
文献类型：
--
作者：
Marks, GB;Colquhoun, JR;Car, NG
背景-一项研究进行了评估的重要性，雷暴作为一种流行病的原因，哮喘急性发作和调查的潜在mechanism. Methods-一个病例对照研究进行了6个城镇在澳大利亚东南部。流行病例日（n = 48）和对照日（n = 191）的随机样本通过参考观察到的哮喘急诊就诊人数与预期人数之间的差异来确定。在这些日子里，雷暴的发生、与之相关的外流和冷锋都是确定的，而对个案的情况一无所知。此外，每小时的花粉计数自动气象站数据的关系进行了详细的研究，在一个严重的流行病的哮喘急性发作。主要的结果措施是哮喘急性发作的流行病的数量。结果雷暴外流检测到33%的流行病日，只有3%的控制日（比值比15.0，95%的置信区间6.0至37.6）。这种关联在春末和夏季最强。一个严重的流行病的详细检查表明，它的发病正好与雷暴外流的到来和4-12倍的草花粉颗粒的环境浓度增加。结论-这些研究结果是一致的假设，即一些流行病的哮喘恶化是由高浓度的过敏性颗粒所产生的外流冷空气，与雷暴的下沉气流，把花粉粒和微粒扫起来，然后把它们集中在地面上的一条浅空气带里。这是花粉季节哮喘恶化的常见原因。
Background-A study was undertaken to assess the importance of thunderstorms as a cause of epidemics of asthma exacerbations and to investigate the underlying mechanism.Methods-A case control study was performed in six towns in south eastern Australia. Epidemic case days (n = 48) and a random sample of control days (n = 191) were identified by reference to the difference between the observed and expected number of emergency department attendances for asthma. The occurrence of thunderstorms, their associated outflows and cold fronts were ascertained, blind to case status, for each of these days. In addition, the relation of hourly pollen counts to automatic weather station data was examined in detail for the period around one severe epidemic of asthma exacerbations. The main outcome measure was the number of epidemics of asthma exacerbations.Results-Thunderstorm outflows were detected on 33% of epidemic days and only 3% of control days (odds ratio 15.0, 95% confidence interval 6.0 to 37.6). The association was strongest in late spring and summer. Detailed examination of one severe epidemic showed that its onset coincided with the arrival of the thunderstorm outflow and a 4-12 fold increase in the ambient concentration of grass pollen grains.Conclusions-These findings are consistent with the hypothesis that some epidemics of exacerbations of asthma are caused by high concentrations of allergenic particles produced by an outflow of colder air, associated with the downdraught from a thunderstorm, sweeping up pollen grains and particles and then concentrating them in a shallow band of air at ground level. This is a common cause of exacerbations of asthma during the pollen season.