Abstract

Background:

Developmental exposure to air pollution is associated with diminished cognitive abilities in observational studies, but no randomized controlled trial has examined the effect of reducing air pollution on cognition in children.

Objectives:

We sought to quantify the impact of reducing exposure to particulate matter (PM) during pregnancy on children’s cognitive performance at 4 y of age.

Methods:

In this single-blind, parallel-group, randomized controlled trial in Ulaanbaatar, Mongolia, we randomly assigned 540 nonsmoking pregnant women (268 intervention and 272 control) to receive 1–2 portable high-efficiency particulate air (HEPA) filter air cleaners or no air cleaners. The air cleaners were used from a median of 11 wk gestation until the end of pregnancy. The primary outcome was full-scale intelligence quotient (FSIQ) assessed using the Wechsler Preschool and Primary Scale of Intelligence, Fourth Edition (WPPSI-IV) when children were a median of 48 months old. We imputed missing outcome data using multiple imputation with chained equations, and our primary analysis was by intention to treat.

Results:

After excluding known miscarriages, stillbirths, neonatal deaths, and medical conditions that impeded cognitive testing and imputation, 475 (233 control and 242 intervention) children were included in our analyses. In an unadjusted analysis, the mean FSIQ of children who were randomly assigned to the intervention group was 2.5 points [95% confidence interval (CI): $-0.4$, 5.4 points] higher than that of children in the control group. After adjustment to account for an imbalance in preterm birth between groups, the effect estimate increased to 2.8 points (95% CI: $-0.1$, 5.7).

Conclusions:

Reducing PM air pollution during pregnancy may improve cognitive performance in childhood. https://doi.org/10.1289/EHP10302

中文翻译：

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便携式 HEPA 过滤空气净化器在怀孕期间的使用和四岁儿童的认知表现：UGAAR 随机对照试验

摘要

背景：

在观察性研究中，发育性暴露于空气污染与认知能力下降有关，但没有随机对照试验检查减少空气污染对儿童认知能力的影响。

目标：

我们试图量化减少怀孕期间接触颗粒物 (PM) 对 4 岁儿童认知能力的影响。

方法：

在蒙古乌兰巴托的这项单盲、平行组、随机对照试验中，我们随机分配 540 名不吸烟孕妇（268 名干预组和 272 名对照组）接受 1-2 台便携式高效微粒空气 (HEPA) 过滤空气净化器或没有空气净化器。从妊娠 11 周到妊娠结束的中位时间使用空气净化器。主要结果是使用韦克斯勒学前和初级智力量表第四版 (WPPSI-IV) 评估的儿童中位数为 48 个月大的全面智商 (FSIQ)。我们使用链式方程的多重插补来插补缺失的结果数据，我们的主要分析是意向治疗。

结果：

在排除已知的流产、死产、新生儿死亡和阻碍认知测试和插补的医疗条件后，我们的分析中包括了 475 名（233 名对照和 242 名干预）儿童。在未经调整的分析中，被随机分配到干预组的儿童的平均 FSIQ 为 2.5 分 [95% 置信区间 (CI)：$-0.4$, 5.4 分] 高于对照组儿童。在考虑组间早产的不平衡进行调整后，效果估计值增加到 2.8 分（95% CI：$-0.1$, 5.7)。

结论：

减少怀孕期间的 PM 空气污染可能会提高儿童时期的认知能力。https://doi.org/10.1289/EHP10302