Table 4.
Behavior and imaging changes associated with air copper (copper range, 3.7–13.8 ng/m3)
| Whole sample (n = 2827) | Mean ± SD | β Coefficient (adjusted β)b | 95% CI (adjusted 95% CI) | t | P |
|---|---|---|---|---|---|
| Motor speed (reaction time) | 671 ± 124 msec | 2.2 (4.7) ms/(ng/m3) | 0.6 to 3.7 (1.8 to 7.5) ms/(ng/m3) | 2.7 | 0.006 |
| Motor response consistency (reaction time SD) | 235 ± 91 msec | 2.9 (3.4) ms/(ng/m3) | 1.7 to 4.0 (1.4 to 5.5) ms/(ng/m3) | 4.9 | 8e‐7 |
| MRI sample (n = 261)a | |||||
| Motor response consistency (reaction time SD) | 224 ± 91 msec | 4.2 (9.6) ms/(ng/m3) | 0.5 to 7.9 (1.7 to 17.6) ms/(ng/m3) | 2.2 | 0.026 |
| Gray matter concentration L caudate nucleus | 14.2 ± 3.9 GMc | 0.3 (0.3) GMc/(ng/m3) | 0.1 to 0.4 (0.1 to 0.5) GMc/(ng/m3) | 3.1 | 0.001 |
| Fractional anisotropy DTI L caudate nucleus | 16 ± 1 FAi | 0.1 (0.1) FAi/(ng/m3) | 0.06 to 0.2 (0.05 to 0.2) FAi/(ng/m3) | 3.9 | 0.0001 |
| Functional connectivity L frontal cortex to L caudate | 0.3 ± 1.1 FCi | −0.1 (−0.1) FCi/(ng/m3) | −0.14 to −0.05 (−0.2 to −0.1) FCi/(ng/m3) | −4.4 | 0.00001 |
SD, standard deviation; β, β coefficients from the regressions with copper as the predictor factor; GMc, percentage of gray matter concentration; FAi, anisotropy index expressed in the range of 0–100 units; FCi, strength of functional connectivity expressed in arbitrary units.
a
n varied in each imaging modality (see Methods section).
b
Socioeconomic status, a general indicator of traffic pollution (elemental carbon) and other potentially toxic agents (Pb, Mn, Sb, and Fe) were used in the adjusted model.