空气污染与健康（2）

——1岁儿童的高空气污染暴露与12岁时的大脑结构发生变化有关。

诸平

Fig. 1 These brain images of 12-year-old children show regions of the brain in red, orange and yellow that are most affected by traffic related air pollution (TRAP). Those regions denote a reduction in cortical thickness linked to elemental carbon attributed to traffic. Of these images, the darker the color, the stronger the effect. The study appears in  PLoS ONE. Credit: Cincinnati 

据美国辛辛那提儿童医院医疗中心（Cincinnati Children's Hospital Medical Center）2020年1月24日提供的消息，该中心的研究结果显示，这些12岁儿童的大脑图像显示了受交通相关空气污染（traffic-related air pollution简称TRAP）影响结果，其中影响最大的为红色，橙色和黄色区域表示一次减弱（见图1所示）。这些区域表示与交通相关的元素碳有​​关的皮质厚度的减少。在这些图像中，颜色越深，效果越强。该研究发表在PLoS One中。图1是由辛辛那提儿童医院医疗中心提供。这项新的研究表明，儿童早期大量暴露于与交通有关的空气污染（TRAP）与12岁时大脑的结构变化有关。辛辛那提儿童医院医学中心的研究发现，与较低暴露水平的儿童相比，出生时TRAP暴露水平较高的儿童在12岁时灰质体积和皮质厚度降低。

辛辛那提儿童医院的研究人员，该研究的第一作者，也是通讯作者特拉维斯·贝克维斯（Travis Beckwith）博士说：“这项研究的结果尽管具有探索性，但表明您的住所和呼吸空气会影响大脑的发育。”“虽然损失的百分比远远小于在退行性疾病状态下所看到的损失，但这种损失可能足以影响各种身心过程的发展。”

灰质包括参与运动控制和感觉知觉（例如视觉和听觉）的大脑区域。皮质厚度反映了外部灰质的深度。研究发现，额叶和顶叶以及小脑的特定区域受到的影响减少了3%～4％。

特拉维斯·贝克维斯博士说：“婴儿如果早期使大脑发育接受了TRAP不可逆转地损害，则无论后续检查的时间点如何，结构受损后果都可能持续存在。”

辛辛那提大学医学院（University of Cincinnati College of Medicine）的研究人员将其在2020年1月24日发表于PLoS ONE杂志——Travis Beckwith, Kim Cecil, Mekibib Altaye, Rachel Severs, Christopher Wolfe, Zana Percy, Thomas Maloney, Kimberly Yolton, Grace LeMasters, Kelly Brunst, Patrick Ryan. Reduced gray matter volume and cortical thickness associated with traffic-related air pollution in a longitudinally studied pediatric cohort. PLoS ONE, 2020, 15(1): e0228092. Published: January 24, 2020. https://doi.org/10.1371/journal.pone.0228092.他们使用磁共振成像获得了147位12岁儿童的解剖学大脑图像。这些孩子是辛辛那提儿童过敏和空气污染研究（Cincinnati Childhood Allergy and Air Pollution Study, CCAAPS）的一部分，该研究招募了孩子年龄不足6个月大的志愿者，以检查儿童早期接触TRAP和健康状况的情况(health outcomes)。

CCAAPS中的志愿者在他们出生后的第一年中，TRAP暴露水平较高或较低的判断标准是研究人员使用辛辛那提地区27个地点的空气采样网络估算其暴露程度，并在不同季节同时在4个或5个地点同时进行了24/7采样。参与的儿童在监护人的陪同之下，分别在1、2、3、4、7和12岁时完成了门诊检查。

TRAP的先前研究表明，它会导致神经退行性疾病和神经发育障碍。这项工作支持TRAP在生命早期改变大脑结构。参与此项研究的除了辛辛那提大学医学院和辛辛那提儿童医院医学中心的研究人员之外，还有来自西肯塔基大学（Western Kentucky University）的研究人员。更多信息请注意浏览原文或者相关报道，诸如将空气污染与儿童心理健康问题联系起来（Studies link air pollution to mental health issues in children）。

Abstract

Early life exposure to air pollution poses a significant risk to brain development from direct exposure to toxicants or via indirect mechanisms involving the circulatory, pulmonary or gastrointestinal systems. In children, exposure to traffic related air pollution has been associated with adverse effects on cognitive, behavioral and psychomotor development. We aimed to determine whether childhood exposure to traffic related air pollution is associated with regional differences in brain volume and cortical thickness among children enrolled in a longitudinal cohort study of traffic related air pollution and child health. We used magnetic resonance imaging to obtain anatomical brain images from a nested subset of 12 year old participants characterized with either high or low levels of traffic related air pollution exposure during their first year of life. We employed voxel-based morphometry to examine group differences in regional brain volume, and with separate analyses, changes in cortical thickness. Smaller regional gray matter volumes were determined in the left pre- and post-central gyri, the cerebellum, and inferior parietal lobe of participants in the high traffic related air pollution exposure group relative to participants with low exposure. Reduced cortical thickness was observed in participants with high exposure relative to those with low exposure, primarily in sensorimotor regions of the brain including the pre- and post-central gyri and the paracentral lobule, but also within the frontal and limbic regions. These results suggest that significant childhood exposure to traffic related air pollution is associated with structural alterations in brain.

相关研究：

Kelly J. Brunst et al, Myo-inositol mediates the effects of traffic-related air pollution on generalized anxiety symptoms at age 12 years, Environmental Research (2019). DOI: 10.1016/j.envres.2019.05.009

Cole Brokamp, Jeffrey R. Strawn, Andrew F. Beck, Patrick Ryan. Pediatric Psychiatric Emergency Department Utilization and Fine Particulate Matter: A Case-Crossover Study. Environmental Health Perspectives, Published: 25 September 2019, 127(9): https://ehp.niehs.nih.gov/doi/10.1289/ehp4815

https://medicalxpress.com/news/2019-05-team-links-traffic-related-air-pollution.html