Department of Environmental Health-Exposure, Epidemiology and Risk Program, Harvard School of Public Health, Landmark Center, 401 Park Dr West, Boston, MA 02215, USA.
Environ Health. 2012 Jun 18;11:40. doi: 10.1186/1476-069X-11-40.
Adverse birth outcomes such as low birth weight and premature birth have been previously linked with exposure to ambient air pollution. Most studies relied on a limited number of monitors in the region of interest, which can introduce exposure error or restrict the analysis to persons living near a monitor, which reduces sample size and generalizability and may create selection bias.
We evaluated the relationship between premature birth and birth weight with exposure to ambient particulate matter (PM₂.₅) levels during pregnancy in Massachusetts for a 9-year period (2000-2008). Building on a novel method we developed for predicting daily PM₂.₅ at the spatial resolution of a 10x10 km grid across New-England, we estimated the average exposure during 30 and 90 days prior to birth as well as the full pregnancy period for each mother. We used linear and logistic mixed models to estimate the association between PM₂.₅ exposure and birth weight (among full term births) and PM₂.₅ exposure and preterm birth adjusting for infant sex, maternal age, maternal race, mean income, maternal education level, prenatal care, gestational age, maternal smoking, percent of open space near mothers residence, average traffic density and mothers health.
Birth weight was negatively associated with PM₂.₅ across all tested periods. For example, a 10 μg/m³ increase of PM₂.₅ exposure during the entire pregnancy was significantly associated with a decrease of 13.80 g [95% confidence interval (CI) = -21.10, -6.05] in birth weight after controlling for other factors, including traffic exposure. The odds ratio for a premature birth was 1.06 (95% confidence interval (CI) = 1.01-1.13) for each 10 μg/m3 increase of PM₂.₅ exposure during the entire pregnancy period.
The presented study suggests that exposure to PM₂.₅ during the last month of pregnancy contributes to risks for lower birth weight and preterm birth in infants.
低出生体重和早产等不良出生结局此前与接触环境空气污染有关。大多数研究依赖于感兴趣区域内有限数量的监测器，这可能会导致暴露误差或限制分析仅限于靠近监测器的人，从而减少样本量和通用性，并可能产生选择偏差。
我们评估了在马萨诸塞州进行的为期 9 年（2000-2008 年）的怀孕期间，早产和出生体重与环境细颗粒物（PM₂.₅）暴露之间的关系。基于我们为预测新英格兰地区 10x10 公里网格空间分辨率的每日 PM₂.₅而开发的新方法，我们估计了每个母亲在分娩前 30 天和 90 天以及整个孕期的平均暴露量。我们使用线性和逻辑混合模型来估计 PM₂.₅暴露与出生体重（足月出生）之间以及 PM₂.₅暴露与早产之间的关联，同时调整婴儿性别、母亲年龄、母亲种族、平均收入、母亲教育水平、产前护理、胎龄、母亲吸烟、母亲居住地附近开放空间的百分比、平均交通密度和母亲健康状况等因素。
在所有测试期间，出生体重与 PM₂.₅呈负相关。例如，在整个怀孕期间，PM₂.₅暴露增加 10μg/m³，与出生体重下降 13.80g 显著相关[95%置信区间（CI）=-21.10，-6.05]，在控制其他因素（包括交通暴露）后。在整个孕期，PM₂.₅暴露每增加 10μg/m³，早产的比值比为 1.06（95%置信区间（CI）=1.01-1.13）。
本研究表明，妊娠最后一个月接触 PM₂.₅会增加婴儿出生体重低和早产的风险。
