Effects of Fine Particle Composition on Birth Outcomes

描述（由申请人提供）：早产、低出生体重和小胎龄（SGA）是美国婴儿死亡和严重发病率的主要原因。对于非裔美国人来说，这些风险几乎翻了一番。几项研究表明，空气污染，特别是<2.5mm的颗粒物（PM2.5）是不良出生结局的危险因素。这项研究的一个挑战是，颗粒的化学成分因地区和季节的不同而变化很大。由于缺乏关于哪种类型的颗粒最有害的科学证据，颗粒按大小进行调节。我们将研究颗粒物化学成分的两个方面：1)PM2.5单个化学成分（如镍）的水平；2)特定来源（如石油燃烧）的PM2.5水平，以调查暴露于特定类型颗粒与出生结果之间的关系。我们从8个CT和MA监测点获得了用于测量PM2.5总质量的过滤器。我们将分析这些过滤器，以确定49种化学成分的含量。这些化学成分数据将用于源分配建模，以估计来自特定源（例如机动车辆）的PM2.5。我们的主要结局是出生体重（连续），低出生体重<2500克，极低出生体重<1500克，早产<37周，非常早产<32周，胎龄小（胎龄体重<10百分位体重），使用CT和MA出生证明数据（2001-2006年）在监测点30公里内出生（N=213,000）。将评估出生结果与PM2.5化学成分之间的关联（目标1），以及出生结果与特定来源的PM2.5水平之间的关联（目标2）。在目标3中，我们将用三种暴露方法检查交通PM2.5: 1)与目标1中交通最相关的化学成分；2) Aim 2的交通PM2.5水平；3)利用GIS交通模型估算与交通相关的空气污染。在我们的初步研究中，暴露于特定PM2.5成分每增加四分位数范围（IQR），低出生体重风险增加8-13%。暴露于特定PM2.5成分或PM2.5源导致的IQR变化导致的任何结果（包括极低出生体重，患病率1.5%）风险增加10%的概率为90%。将在相互作用模型中调查关联，以测试效果是否因种族而异。这项研究的结果将确定对出生结果影响最大的PM2.5成分或来源，并可能导致针对对婴儿健康最有害的来源的干预措施。

DESCRIPTION (provided by applicant): Preterm delivery, low birth weight and small for gestational age (SGA) are major causes of infant mortality and severe morbidity in the U.S. For African Americans, these risks are nearly doubled. Several studies have implicated air pollution, especially particulate matter <2.5mm (PM2.5) as a risk factor for adverse birth outcomes. A challenge in this research is that particles vary widely in chemical composition by region and season. Due to lack of scientific evidence on which types of particles are most harmful, particles are regulated by size. We will investigate two aspects of the chemical composition of particles: 1) levels of individual PM2.5 chemical components (e.g., nickel); and 2) levels of PM2.5 from specific sources (e.g. oil combustion), to investigate the relationship between exposure to specific types of particles and birth outcomes. We obtained filters from 8 CT and MA monitoring sites that were used to measure PM2.5 total mass. We will analyze these filters to determine levels of 49 chemical components. This chemical component data will be used in source apportionment modeling to estimate PM2.5 from specific sources (e.g. motor vehicles). Our primary outcomes will be birth weight (continuous), low birth weight <2500 gm, very low birth weight <1500 gm, preterm birth <37 wks, very preterm birth <32 wks, and small for gestational age (<10th percentile weight for gestational age), using CT and MA birth certificate data for births (2001-2006) within 30 km of the monitoring sites (N=213,000). Associations will be assessed between birth outcomes and PM2.5 chemical components (Aim 1) and between birth outcomes and the levels of PM2.5 from particular sources (Aim 2). In Aim 3 we will examine traffic PM2.5 with three exposure methods: 1) the chemical component most associated with traffic from Aim 1; 2) traffic PM2.5 levels from Aim 2; and 3) traffic-related air pollution estimated through a GIS traffic model. In our preliminary studies, risk of low birth weight increased 8-13% per interquartile range (IQR) increase in exposure to specific PM2.5 components. We will have >90% power to detect a 10% increase in risk of any outcome (including very low birth weight, prevalence 1.5%) associated with an IQR change exposure to a specific PM2.5 component or PM2.5 source. Associations will be investigated in interaction models to test whether effects differ by race. Findings from this study will identify the components or sources of PM2.5 with the greatest impact on birth outcomes and could lead to interventions targeted at the sources most toxic to infant health.