Role of Diesel and Other Vehicular Exhaust in Exacerbation of Childhood Asthma

描述（由申请人提供）：儿童哮喘的负担不成比例地影响生活在贫困和城市中心的儿童，其中许多是少数民族。对于那些生活在交通密度高的城市环境中的人来说，人们越来越关注柴油和其他车辆废气对呼吸系统健康的潜在不利影响。流行病学研究表明，暴露于高交通量，特别是高卡车交通量-城市环境中柴油废气的主要来源-与哮喘症状，哮喘住院和肺功能下降的增加之间存在关联。然而，由于将柴油与火花点火废气以及一般车辆废气与其他污染源分离的挑战，暴露于柴油和其他车辆废气与不利的呼吸系统健康结果之间的定量关联尚未得到很好的表征。本研究将描述与汽车尾气和其他特定空气污染源相关的环境暴露，并评估这些暴露与生活在底特律和密歇根州迪尔伯恩的儿童哮喘恶化的关系。我们将收集环境及室内家居空气质素数据，提供高时空分辨率的污染浓度，并利用最先进的统计/地理空间模型，以分配污染物来源（包括柴油及其他车辆废气）的暴露量，以及制定个别特定的暴露量估计。我们将进行一项为期两年的纵向研究，涉及210名哮喘儿童，其中70名儿童分别居住在高交通/高卡车量道路附近、高交通/低卡车量道路附近和远离高交通道路。在八个季节中的每一个季节中连续两周评估的每日健康措施将包括呼吸道症状、通过手持式肺量计评估的肺功能、药物使用和卫生服务利用。我们假设：1）与其他污染源相比，柴油和其他车辆废气的特定暴露是生活在高交通密度城市环境中的哮喘儿童不良健康状况的更强预测因子，2）家庭中吸烟者的存在，家庭灰尘中常见过敏原的高水平，或对此类过敏原的致敏性，将产生柴油和其他车辆废气与不利的呼吸系统健康结果之间更强的可靠性-响应关系。

DESCRIPTION (provided by applicant): The burden of childhood asthma disproportionately affects children living in poverty and in urban centers, many of whom are minority ethnic groups. For those living in urban environments with high traffic densities, there is increasing concern about potential adverse respiratory health effects of exposure to diesel and other vehicular exhaust. Epidemiologic studies have shown associations between exposure to high traffic volumes, and especially to high truck traffic - the main source of diesel exhaust in urban settings - and increases in asthma symptoms, asthma hospitalizations, and decreased lung function. Yet, owing to the challenges of separating diesel from spark ignition exhaust, and vehicular exhaust in general from other sources of pollution, quantitative associations between exposure to diesel and other vehicular exhaust and adverse respiratory health outcomes have not been well-characterized. This study will characterize ambient exposures related to vehicular exhaust and other specific air pollutant sources, and evaluate the relationship of these exposures to the exacerbation of asthma among children living in Detroit and Dearborn, Michigan. We will collect ambient and indoor household air quality data which provides both high temporal and spatial resolution of pollution concentrations and utilize state-of-the-art statistical/geospatial models to apportion exposures among pollutant sources including diesel and other vehicular exhaust and to develop individual- specific exposure estimates. We will conduct a two-year longitudinal study involving 210 asthmatic children with 70 each living near high traffic/high truck volume roads, near high traffic/low truck volume roads, and distant from high traffic roads. Daily health measures to be assessed for two consecutive weeks in each of eight seasons will include respiratory symptoms, pulmonary function assessed by hand-held spirometers, medication use, and health services utilization. We hypothesize that: 1) exposures specific to diesel and other vehicular exhaust will be stronger predictors of adverse health status among children with asthma living in a high traffic density urban environment than other pollutant sources, and, 2) the presence of cigarette smokers in the household, high levels of common allergens in household dust, or sensitization to such allergens, will yield stronger exposure-response relationships between diesel and other vehicular exhaust and adverse respiratory health outcomes.