Indoor woodsmoke PM and asthma: a randomized trial

描述（由申请人提供）：尽管颗粒物（PM）暴露与不良呼吸健康结果有关，但这些研究中的大多数都集中在城市和工业PM2.5来源的空气散逸。木材烟雾产生的PM也是这些城市地区环境PM的贡献者，并且是许多美国农村或城郊地区以及发展中国家许多社区PM的主要来源。这项研究将集中在室内空气质量和临床相关变化的健康影响哮喘患者生活在家庭的主要热源是非EPA认证的柴炉。本研究的主要目的是评估居民干预措施减少木炉室内PM暴露的有效性，以及哮喘儿童生活质量和健康结局的相应改善。该项目的研究区域将是爱达荷州和蒙大拿州西部的三个农村社区，包括一个印第安人保留地。本研究将使用三组（Tx1、Tx2和Tx3）随机安慰剂对照干预试验。干预措施将在家庭一级进行，并将评估每个家庭中一名哮喘儿童的暴露情况和结果。Tx1的家庭将收到无效的高效微粒空气（HEPA）装置，并将作为安慰剂组。Tx2的家庭将收到一个新的EPA认证的柴炉，而Tx3的家庭将收到有源HEPA设备。本研究的次要目的是评估这些干预措施对住宅PM2.5暴露和其他健康结果的影响。干预前后测量的二次暴露结果将包括PM2.5质量、PM2.5过滤器上的化学木材烟雾标记物（包括左旋葡聚糖和松香酸）以及尿液和呼出气冷凝物中木材烟雾暴露的生物标志物。在干预之前和之后测量的次要哮喘相关健康结果将包括峰值呼气流量（PEF）和第一秒用力呼气量（FEV1）、呼出气冷凝物中的生物标志物（即，pH和一氧化氮），以及哮喘症状的频率，药物使用和医疗保健利用。据我们所知，这将是美国第一个利用木材烟雾干预来评估室内PM减少对易感人群健康结果的影响的随机试验。该项目的成果将可推广到美国和世界其他地区，在这些地区，生物质燃烧通常用于加热和烹饪。相关性：这项研究将确定减少住宅柴炉的PM2.5（室内空气污染的常见来源）是否会改善哮喘儿童的健康状况。将测量具有临床意义的健康结果。这项研究的结果将为在这种常见暴露的情况下实施哮喘管理的公共卫生策略提供重要信息。

DESCRIPTION (provided by applicant): Although particulate matter (PM) exposures have been linked with poor respiratory health outcomes, most of these studies have focused on air sheds with urban and industrial sources of PM2.5. Wood smoke-derived PM also contributes to ambient PM in these urban areas, and is the major source of PM in many US rural or peri-urban areas, as well as in many communities within developing countries. This study will focus on indoor air quality and clinically relevant changes in health effects among asthmatics living in homes whose primary heating sources are non EPA-certified woodstoves. The Primary Aim of this study is to assess the efficacy of residential interventions to reduce indoor PM exposure from woodstoves and the corresponding improvements in quality of life and health outcomes for asthmatic children. The study area for this project will be three rural communities in Idaho and western Montana, including one Indian Reservation. This study will use a three arm (Tx1, Tx2, and Tx3) randomized placebo-controlled intervention trial. The interventions will be at the household level, and exposure and outcomes will be assessed for one asthmatic child in each household. Households in Tx1 will receive inactive high efficiency particulate air (HEPA) devices and will serve as the placebo group. Households in Tx2 will receive a new EPA-certified woodstove, while households in Tx3 will receive active HEPA devices. The Secondary Aims of this study are to assess the impact of these interventions on residential PM2.5 exposures and other health outcomes. Secondary exposure outcomes measured prior to and following the intervention will include PM2.5 mass, chemical wood smoke markers on PM2.5 filters (including levoglucosan and abietic acids), and biomarkers of wood smoke exposure in urine and exhaled breath condensate. Secondary asthma-related health outcomes measured prior to and following the intervention will include peak expiratory flow (PEF) and forced expiratory volume in first second (FEV1), biomarkers in exhaled breath condensate (i.e., pH and nitric oxide), and frequency of asthma symptoms, medication usage, and healthcare utilization. To our knowledge, this will be the first randomized trial in the US to utilize a wood smoke intervention to assess the impact of the consequent reductions in indoor PM on health outcomes in a susceptible population. The results from this project will be translatable to other regions in the US and the world where biomass burning is commonly used for heating and cooking. Relevance: This study will determine if reductions in PM2.5 from residential woodstoves, a common source of indoor air pollution, will result in health improvements among asthmatic children. Clinically significant health outcomes will be measured. Results from this study will provide important information for implementing public health strategies for asthma management in the presence of this common exposure.