Of the significant phenotypic correlations between cigarette pack-years and neocortical volume, five were detected in cingulate and temporal lobe regions including left pars orbitalis and bilateral rostral middle frontal regions of the frontal lobe, the left posterior cingulate, left middle temporal gyrus and right inferior temporal gyrus (-0.14 < rP < -0.07, p = 0.0001 -0.02). Unique environmental factors shared between cigarette pack-years and these ROIs substantially contributed to these correlations (-0.14 < covE < -0.07; p = 0.0002-0.01; Table I). The magnitude of the unique environmental correlations indicate moderate overlap between the shared environmental influences which increase cigarette pack-years and decrease volume in these ROIs (-0.31 < rE < -0.21). After correction for multiple testing using FDR, these results were no longer significant.
