Computed tomography (CT) studies with cohorts ranging from middle-aged to older adults report that chronic smoking is associated with an abnormal increase of global brain atrophy with advancing age [74–77]. These CT studies assessed whole brain volumes and did not report major anatomical subdivisions (e.g., frontal gray matter/white matter). An early MRI study with older adults examined global brain atrophy over a 5-year-interval and found higher pack years was related to increased ventricular volume in men and was associated with increased sulcal volume in women, after controlling for age and vascular risk factors [78]. More recent MRI studies have employed voxel-based morphological measures to assess the regional brain volumes and densities of the cortical gray matter (GM). Smokers aged 39.5 ± 10.3 years evidenced smaller volumes and lower tissue densities than did NSC in bilateral anterior frontal lobe regions; smokers also had smaller volume of the left dorsal cingulate cortex and lower GM density in the cerebellum. Anterior frontal cortex density was inversely related to pack-years [79]. Smokers aged 30.8 ± 7.5 years demonstrated widespread GM volume and density reductions
