ISGLOBAL, Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; Pompeu Fabra University, Barcelona, Catalonia, Spain; Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain.
MRI Research Unit, Hospital del Mar, Barcelona, Spain; Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM G21, Barcelona, Spain.
Environ Int. 2017 Aug;105:12-19. doi: 10.1016/j.envint.2017.04.011. Epub 2017 May 5.
Polycyclic aromatic hydrocarbons (PAHs) have been proposed as environmental risk factors for attention deficit hyperactivity disorder (ADHD). The effects of these pollutants on brain structures potentially involved in the pathophysiology of ADHD are unknown.
The aim of this study was to investigate the effects of PAHs on basal ganglia volumes and ADHD symptoms in school children.
We conducted an imaging study in 242 children aged 8-12years, recruited through a set of representative schools of the city of Barcelona, Spain. Indoor and outdoor PAHs and benzo[a]pyrene (BPA) levels were assessed in the school environment, one year before the MRI assessment. Whole-brain volumes and basal ganglia volumes (caudate nucleus, globus pallidus, putamen) were derived from structural MRI scans using automated tissue segmentation. ADHD symptoms (ADHD/DSM-IV Scales, American Psychiatric Association 2002) were reported by teachers, and inattentiveness was evaluated with standard error of hit reaction time in the attention network computer-based test.
Total PAHs and BPA were associated with caudate nucleus volume (CNV) (i.e., an interquartile range increase in BPA outdoor level (67pg/m) and indoor level (76pg/m) was significantly linked to a decrease in CNV (mm) (β=-150.6, 95% CI [-259.1, -42.1], p=0.007, and β=-122.4, 95% CI [-232.9, -11.8], p=0.030 respectively) independently of intracranial volume, age, sex, maternal education and socioeconomic vulnerability index at home). ADHD symptoms and inattentiveness increased in children with higher exposure to BPA, but these associations were not statistically significant.
Exposure to PAHs, and in particular to BPA, is associated with subclinical changes on the caudate nucleus, even below the legislated annual target levels established in the European Union. The behavioral consequences of this induced brain change were not identified in this study, but given the caudate nucleus involvement in many crucial cognitive and behavior processes, this volume reduction is concerning for the children's neurodevelopment.
多环芳烃（PAHs）已被提出作为注意力缺陷多动障碍（ADHD）的环境风险因素。这些污染物对潜在参与 ADHD 病理生理学的大脑结构的影响尚不清楚。
本研究旨在调查 PAHs 对学龄儿童基底节体积和 ADHD 症状的影响。
我们对 242 名 8-12 岁的儿童进行了一项影像学研究，这些儿童是通过西班牙巴塞罗那市的一系列代表性学校招募的。在 MRI 评估前一年，对学校环境中的室内和室外 PAHs 和苯并[a]芘（BPA）水平进行了评估。使用自动组织分割技术从结构 MRI 扫描中得出全脑体积和基底节体积（尾状核、苍白球、壳核）。ADHD 症状（美国精神病学会 2002 年 ADHD/DSM-IV 量表）由教师报告，在基于注意力网络的计算机测试中，用标准错误的击中反应时间评估注意力不集中。
总 PAHs 和 BPA 与尾状核体积（CNV）相关（即 BPA 室外水平（67pg/m）和室内水平（76pg/m）的一个四分位距增加与 CNV 减少（mm）显著相关（β=-150.6，95%CI[-259.1，-42.1]，p=0.007 和β=-122.4，95%CI[-232.9，-11.8]，p=0.030），独立于颅内体积、年龄、性别、母亲教育程度和家庭中的社会经济脆弱性指数）。暴露于 BPA 的儿童的 ADHD 症状和注意力不集中增加，但这些关联没有统计学意义。
接触 PAHs，特别是 BPA，与尾状核的亚临床变化有关，即使在欧盟规定的年度目标水平以下也是如此。在这项研究中，没有确定这种诱导的大脑变化的行为后果，但由于尾状核参与许多至关重要的认知和行为过程，这种体积减少令人担忧儿童的神经发育。
