TABLE 3.
Results of the VBM analysis (cluster information and statistical significance) on the correlation between exposure to nitrogen oxides and GM volume (A), and WM volume (B)
| A) GRAY MATTER | |||||||
|---|---|---|---|---|---|---|---|
| cluster size | % cluster | aal label | x | y | x | T max | |
| NO2 | |||||||
| (negative | 484 | 61,6 | Precuneus R | 12 | ‐66 | 54 | 3,80 |
| association) | 38,4 | Parietal Sup R | |||||
| cluster size | % cluster | aal label | x | y | x | T max | |
| PM2.5 | |||||||
| (positive | 417 | 47,0 | Vermis 9 | ‐5 | ‐56 | ‐36 | 3,44 |
| association) | 31,7 | Cerebelum 9 L | |||||
| 10,1 | Cerebelum 9 R | ||||||
| cluster size | % cluster | AAL label | x | y | x | T max | |
| NDVI 300 m | |||||||
| (positive | 441 | 81,0 | Frontal Mid L | ‐39 | 11 | 41 | 4,55 |
| association) | 19,0 | Precentral L | |||||
| 730 | 52,3 | Temporal Pole Sup R | 57 | 11 | ‐5 | 4,13 | |
| 14,4 | Frontal Inf Oper R | ||||||
| 10,4 | Temporal Sup R | ||||||
| 10,3 | Insula R | ||||||
| 528 | 87,3 | Precentral R | 56 | ‐8 | 45 | 3,95 | |
| B) WHITE MATTER | |||||||
|---|---|---|---|---|---|---|---|
| cluster size | % cluster | JHU & AAL label | x | y | x | T max | |
| NO2 | |||||||
| (positive | 892 | 91,7 | Splenium CC | 0 | ‐21 | 23 | 3,82 |
| association) | 306 | 62,4 | Putamen L | ‐29 | ‐14 | 0 | 3,79 |
| 26,8 | Inf Long Fasc L | ||||||
| cluster size | % cluster | JHU & AAL label | x | y | x | T max | |
| PM2.5 | |||||||
| (positive | 881 | 53,0 | Frontal Inf Oper L | ‐38 | 18 | 21 | 4,29 |
| association) | 27,7 | Sup Long Fasc L | |||||
| 14,5 | Frontal Inf Tri L | ||||||
| 1187 | 52,6 | Temporal Sup R | 62 | ‐18 | 6 | 4,24 | |
| 42,9 | Inf Long Fasc R | ||||||
| 2131 | 69 | Cing Cingulate Gyrus R | 14 | ‐48 | 27 | 4,10 | |
| 11,0 | Cingulum Post R | ||||||
| 1652 | 82,7 | Inf Long Fasc L | ‐38 | ‐57 | ‐6 | 3,78 | |
| 1954 | 77,3 | Sup Long Fasc R | 38 | ‐27 | 38 | 3,67 | |
| 350 | 76,3 | Sup Long Fasc R | 39 | 3 | 17 | 3,64 | |
| 11,7 | Frontal Inf Oper R | ||||||
| 347 | 99,4 | Cing Cingulate Gyrus L | ‐17 | ‐29 | 36 | 3,61 | |
| 412 | 77,2 | Forceps Minor | 23 | 30 | ‐11 | 3,45 | |
| 10,2 | Olfactory R | ||||||
| cluster size | % cluster | JHU & AAL label | x | y | x | T max | |
| Lden index | |||||||
| (positive association) | 324 | 100 | Body CC | 0 | ‐18 | 23 | 4,44 |
Notes: Statistical threshold was set to P < .001 (uncorrected) with a minimum extension cluster of 300 voxels (1 cm3). “%cluster” refers to the percentage of the cluster extension that is into the anatomical region determined by the atlas label. Residual contributions (below 10%) are not listed, because they were assumed to be spreading effects due to the smoothing procedure. WM labels in italics correspond to juxta‐cortical voxels of WM, which have been labelled according to the closest GM AAL area. Colors of labels correspond to cluster color in Figure 2 for an easier identification.
Abbreviations: AAL: Anatomical Automatic Labelling (GM); CC: Corpus callosum; GM, gray matter; JHU: Johns Hopkins University WM atlas; Lden index, day‐evening‐night sound average; NDVI, normalized difference vegetation index; WM, white matter.