哮喘联盟

   摘要
   背景:有证据表明暴露于环境空气污染物可触发哮喘发作，然而，哮喘行动计划中缺乏详细的污染物信息。哮喘通常与四个标准污染物相关，该标准是由美国环境保护署得出的。由于多种污染物触发的哮喘发作和风险取决于城市特异性的污染混合物，所以缺乏减少特异性污染物暴露的指导建议。这类指导性建议对于降低污染物触发的哮喘发作风险是非常有必要的，而多污染物统计模型的出现则完全填补了指南与现实之间的鸿沟。本研究评估了在一个受污染的大都市中，暴露于哮喘相关污染物的风险因素，并界定了哮喘发作和污染混合物间的城市特定关联性。本研究目标是将城市特定的污染物风险作为预防发作的附加指导被并入到个人哮喘行动计划中。
   方法：2004至2011年在德克萨斯州休斯顿，采用病例交叉分析和条件Logistic回归分析来评估臭氧、细颗粒物、二氧化氮、二氧化硫和一氧化碳污染与11,754例急救医疗救护车治疗的哮喘发作之间的关联性。单个和多个污染物模型均有介绍。
   结果：在休斯敦，臭氧和二氧化氮是重要的激发物（RR=1.05，95％CI：1.00，1.09），（RR=1.10，95％CI：1.05，1.15），在多污染物模型中，臭氧和二氧化氮分别以20和8 ppb增加。这两种污染物在一年的特定时间会同时增高。当这些污染物被视为同一整体，尤其是伴随浓度增加时，其导致的风险是不同的。臭氧的累积暴露（0-2天的时间差）是有意义的，而对于二氧化氮应关注单日暴露。最高风险的人群为年龄46～66岁、非裔美国人以及男性。
   结论：累积和共存的室外污染物暴露量，是触发哮喘发作重要的归因危险因素，尤其是随浓度增加时。休斯顿个体改善哮喘行动计划应警惕这些污染物、它们发展的趋势、相关关系以及累积效应。本研究研究确定了备受关注的休斯顿二氧化氮水平和3天-臭氧暴露情况，但基于单个污染物的国家标准尚未确定。
 

（林江涛 审校）
Environ Health. 2014 Jul 11;13(1):58. [Epub ahead of print]

 

Using community level strategies to reduce asthma attacks triggered by outdoor air pollution: a case crossover analysis.
 

Raun LH, Ensor KB, Persse D.
 

ABSTRACT
BACKGROUND: Evidence indicates that asthma attacks can be triggered by exposure to ambient air pollutants, however, detailed pollution information is missing from asthma action plans. Asthma is commonly associated with four criteria pollutants with standards derived by the United States Environmental Protection Agency. Since multiple pollutants trigger attacks and risks depend upon city-specific mixtures of pollutants, there is lack of specific guidance to reduce exposure. Until multi-pollutant statistical modeling fully addresses this gap, some guidance on pollutant attack risk is required. This study examines the risks from exposure to the asthma-related pollutants in a large polluted metropolitan city and defines the city-specific association between attacks and pollutant mixtures. Our goal is that city-specific pollution risks be incorporated into individual asthma action plans as additional guidance to prevent attacks.
METHODS: Case-crossover analysis and conditional logistic regression were used to measure the association between ozone, fine particulate matter, nitrogen dioxide, sulfur dioxide and carbon monoxide pollution and 11,754 emergency medical service ambulance treated asthma attacks in Houston, Texas from 2004-2011. Both single and multi-pollutant models are presented.
RESULTS: In Houston, ozone and nitrogen dioxide are important triggers (RR = 1.05; 95% CI: 1.00, 1.09), (RR = 1.10; 95% CI: 1.05, 1.15) with 20 and 8 ppb increase in ozone and nitrogen dioxide, respectively, in a multi-pollutant model. Both pollutants are simultaneously high at certain times of the year. The risk attributed to these pollutants differs when they are considered together, especially as concentrations increase. Cumulative exposure for ozone (0-2 day lag) is of concern, whereas for nitrogen dioxide the concern is with single day exposure. Persons at highest risk are aged 46-66, African Americans, and males.
CONCLUSIONS: Accounting for cumulative and concomitant outdoor pollutant exposure is important to effectively attribute risk for triggering of an asthma attack, especially as concentrations increase. Improved asthma action plans for Houston individuals should warn of these pollutants, their trends, correlation and cumulative effects. Our Houston based study identifies nitrogen dioxide levels and the three-day exposure to ozone to be of concern whereas current single pollutant based national standards do not.
 

Environ Health. 2014 Jul 11;13(1):58. [Epub ahead of print]