Casanova Ramon, Wang Xinhui, Reyes Jeanette, Akita Yasuyuki, Serre Marc L, Vizuete William, Chui Helena C, Driscoll Ira, Resnick Susan M, Espeland Mark A, Chen Jiu-Chiuan
Department of Biostatistical Sciences, Wake Forest School of Medicine Winston-Salem, NC, USA.
Department of Preventive Medicine, University of Southern California Los Angeles, CA, USA.
Front Hum Neurosci. 2016 Oct 13;10:495. doi: 10.3389/fnhum.2016.00495. eCollection 2016.
Exposure to ambient fine particulate matter (PM: PM with aerodynamic diameters < 2.5 μm) has been linked with cognitive deficits in older adults. Using fine-grained voxel-wise analyses, we examined whether PM exposure also affects brain structure. Brain MRI data were obtained from 1365 women (aged 71-89) in the Women's Health Initiative Memory Study and local brain volumes were estimated using RAVENS (regional analysis of volumes in normalized space). Based on geocoded residential locations and air monitoring data from the U.S. Environmental Protection Agency, we employed a spatiotemporal model to estimate long-term (3-year average) exposure to ambient PM preceding MRI scans. Voxel-wise linear regression models were fit separately to gray matter (GM) and white matter (WM) maps to analyze associations between brain structure and PM exposure, with adjustment for potential confounders. Increased PM exposure was associated with smaller volumes in both cortical GM and subcortical WM areas. For GM, associations were clustered in the bilateral superior, middle, and medial frontal gyri. For WM, the largest clusters were in the frontal lobe, with smaller clusters in the temporal, parietal, and occipital lobes. No statistically significant associations were observed between PM exposure and hippocampal volumes. Long-term PM exposures may accelerate loss of both GM and WM in older women. While our previous work linked smaller WM volumes to PM, this is the first neuroimaging study reporting associations between air pollution exposure and smaller volumes of cortical GM. Our data support the hypothesized synaptic neurotoxicity of airborne particles.
暴露于环境细颗粒物（PM：空气动力学直径<2.5μm的颗粒物）与老年人的认知缺陷有关。我们使用细粒度的体素分析，研究了PM暴露是否也会影响脑结构。脑MRI数据来自女性健康倡议记忆研究中的1365名女性（年龄71 - 89岁），并使用RAVENS（标准化空间中的区域体积分析）估计局部脑容量。基于地理编码的居住地点和美国环境保护局的空气监测数据，我们采用时空模型来估计MRI扫描前三年长期暴露于环境PM的情况。将体素线性回归模型分别拟合到灰质（GM）和白质（WM）图谱上，以分析脑结构与PM暴露之间的关联，并对潜在混杂因素进行调整。PM暴露增加与皮质GM和皮质下WM区域的体积减小有关。对于GM，关联集中在双侧额上回、额中回和额内侧回。对于WM，最大的簇位于额叶，颞叶、顶叶和枕叶有较小的簇。在PM暴露与海马体体积之间未观察到统计学上的显著关联。长期PM暴露可能会加速老年女性GM和WM的损失。虽然我们之前的研究将较小的WM体积与PM联系起来，但这是第一项报告空气污染暴露与较小的皮质GM体积之间关联的神经影像学研究。我们的数据支持空气中颗粒物的突触神经毒性假说。
