Background

Few studies have examined concurrent exposure to household endotoxin and traffic-related air pollution in relation to childhood asthma, yet both factors are associated with asthma outcomes.

Objective

To examine whether proximity to a major roadway (a traffic-related air pollution proxy) modifies the estimated effects of indoor endotoxin on asthma outcomes in children.

Methods

Cross-sectional study of 200 children with asthma (ages, 6-14 years) living in Puerto Rico. Residential distance to a major roadway was calculated as the distance from the participant’s residential US census block centroid to the nearest major road. The outcomes of interest were severe asthma exacerbations, missed school days for asthma, atopy, lung function, and bronchodilator response (BDR). Logistic, linear, or negative binomial regression was used for the multivariable analysis.

Results

In the multivariable analysis, there was an interaction between indoor endotoxin and residential distance to a roadway on severe asthma exacerbations (P = .02) and BDR (P = .07). In an analysis stratified by distance to a roadway, each log₁₀-unit increase in endotoxin was associated with 4.21 times increased odds of severe asthma exacerbations among children living within 499 m (the lower 3 quartiles of residential distance) to a road (95% confidence interval, 1.5-12.0). Among subjects living further than 499 m away from a roadway, each log₁₀-unit increase in endotoxin was associated with reduced odds of severe asthma exacerbations (odds ratio, 0.03; 95% confidence interval, 0.001-0.67). Similar but less substantial findings were observed for BDR.

Conclusion

Our findings suggest that residential proximity to a major road modifies the estimated effect of endotoxin on severe asthma exacerbations in children.

中文翻译：

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波多黎各儿童的室内内毒素、靠近主要道路以及哮喘严重恶化。

背景

很少有研究检查与儿童哮喘相关的家庭内毒素和交通相关空气污染的同时暴露，但这两个因素都与哮喘结果有关。

客观的

检查靠近主要道路（与交通相关的空气污染代理）是否会改变室内内毒素对儿童哮喘结果的估计影响。

方法

对居住在波多黎各的 200 名哮喘儿童（6-14 岁）进行的横断面研究。住宅与主要道路的距离计算为参与者的美国人口普查街区质心到最近的主要道路的距离。感兴趣的结果是严重的哮喘发作、哮喘缺课、特应性、肺功能和支气管扩张剂反应 (BDR)。Logistic、线性或负二项式回归用于多变量分析。

结果

在多变量分析中，严重哮喘发作 ( P  = .02) 和 BDR ( P  = .07) 中，室内内毒素与住宅与道路的距离之间存在交互作用。在按距离道路的距离分层的分析中，内毒素每增加_{10 个}单位，与居住在距离道路 499 m（居住距离的下 3 个四分位数）范围内的儿童中严重哮喘发作的几率增加 4.21 倍（95%）置信区间，1.5-12.0）。在距离道路 499 m 以上的受试者中，每人记录₁₀-内毒素的单位增加与严重哮喘发作的几率降低有关（几率比，0.03；95% 置信区间，0.001-0.67）。对于 BDR 观察到类似但不太重要的发现。

结论

我们的研究结果表明，住宅靠近主要道路会改变内毒素对儿童严重哮喘发作的估计影响。