Mowla Sanjida J, Krajewski Alison K, Wilkie Adrien A, Rappazzo Kristen M, Luben Thomas J
Oak Ridge Institute of Science and Education (ORISE) Research Participant at the United States Environmental Protection Agency, Research Triangle Park, NC, USA.
United States Environmental Protection Agency, Office of Research and Development, Center for Public Health & Environmental Assessment, Research Triangle Park, NC, USA.
J Expo Sci Environ Epidemiol. 2025 May 6. doi: 10.1038/s41370-025-00774-2.
Exposures to ambient air pollutants during pregnancy are associated with preterm birth (PTB) in studies that evaluate average pollutant concentrations during potential "windows of susceptibility," referred to as critical windows.
We evaluated associations between ozone (O) or particulate matter <2.5 micrometers (PM) during pregnancy and PTB, using continuous and categorical metrics of average exposure and repeated exceedances of threshold concentrations.
We analyzed data from North Carolina (NC) birth certificates from the NC Birth Defects Monitoring Program, limited to live, singleton births without birth defects and delivered from 2003-2015. The EPA's Fused Air Quality Surface Using Downscaling (fCMAQ) model was used to assign exposures for trimester-average and daily threshold exceedances for O (daily 8-h maximum) and PM (24-h average) at different daily threshold concentrations (O: 55-70 ppb; PM: 20-35 µg/m) during trimesters 1 and 2 of pregnancy. Descriptive statistics, including weighted kappa statistics, were evaluated. Modified Poisson regression models were used to estimate adjusted risk differences (RDs) per 10,000 births.
Among the cohort of 1,368,370 births, 8.4% were PTBs. The number of daily exposure exceedances ranged from 0 to 81 days over different threshold concentrations during trimester 1 or 2. There was slight to moderate agreement in risk associated with trimester average and daily threshold exposures exceedances, with decreased agreement among higher threshold concentrations. RDs ranged from -31 to 29 for average O exposure and from -2 to 89 for repeated O threshold exceedances. RDs ranged from 23 to 120 for average PM exposure and from -227 to 118 for repeated PM exposure.
This study provides insights into the heterogeneity in risk of PTB when assessing different air pollution exposure metrics.
This study investigates the impact of O and PM exposures during pregnancy on the risk of PTB, using measures based on both average concentrations and repeated exceedances of threshold levels. The findings address uncertainties identified in recent NAAQS reviews and suggests that repeated exposure metrics may capture differences in exposure that are not apparent when evaluating average exposure metrics.
在评估潜在“易感窗口”（即关键窗口）期间的平均污染物浓度的研究中，孕期暴露于环境空气污染物与早产（PTB）有关。
我们使用平均暴露的连续和分类指标以及阈值浓度的重复超标情况，评估孕期臭氧（O₃）或细颗粒物（PM₂.₅）与早产之间的关联。
我们分析了北卡罗来纳州（NC）出生缺陷监测项目的出生证明数据，仅限于2003年至2015年出生的无出生缺陷的单胎活产。美国环境保护局（EPA）的利用降尺度融合空气质量表面（fCMAQ）模型用于分配孕期第1和第2孕期不同每日阈值浓度（O₃：55 - 70 ppb；PM₂.₅：20 - 35 μg/m³）下的孕期平均暴露和每日阈值超标情况。评估了包括加权kappa统计在内的描述性统计量。使用修正的泊松回归模型估计每10000例出生的调整风险差异（RDs）。
在1368370例出生队列中，8.4%为早产。在孕期第1或第2孕期，不同阈值浓度下每日暴露超标的天数范围为0至81天。孕期平均暴露和每日阈值暴露超标相关风险之间存在轻度至中度一致性，阈值浓度越高一致性越低。平均O₃暴露的RDs范围为 - 3¹至29，O₃阈值重复超标的RDs范围为 - 2至89。平均PM₂.₅暴露的RDs范围为23至120，PM₂.₅重复暴露的RDs范围为 - 227至118。
本研究为评估不同空气污染暴露指标时早产风险的异质性提供了见解。
本研究使用基于平均浓度和阈值水平重复超标的测量方法，调查孕期O₃和PM₂.₅暴露对早产风险的影响。研究结果解决了近期国家环境空气质量标准（NAAQS）审查中确定的不确定性，并表明重复暴露指标可能捕捉到评估平均暴露指标时不明显的暴露差异。
