title: Chronic cigarette smoking and the microstructural integrity of white matter in healthy adults: a diffusion tensor imaging study.
abstract: Results from recent studies suggest that chronic cigarette smoking is associated with increased white matter volume in the brain as determined by in vivo neuroimaging. We used diffusion tensor imaging to examine the microstructural integrity of the white matter in 10 chronic smokers and 10 nonsmokers. All individuals were healthy, without histories of medical or psychiatric illness. Fractional anisotropy (FA) and trace were measured in the genu, body, and splenium of the corpus callosum. FA provides a measure of directional versus nondirectional water diffusion, whereas trace provides a measure of nondirectional water diffusion. Lower FA and higher trace values are considered to reflect less brain integrity. Voxel-based morphometry was used to define volumes in each of these regions of the corpus callosum. Chronic smokers exhibited significantly higher FA in the body and whole corpus callosum and a strong trend for higher FA in the splenium compared with nonsmokers. FA did not differ between groups in the genu, and neither trace nor white matter volumes differed between groups in any of the regions of interest. When subdivided by Fagerström score (low vs. high), the low Fagerström group exhibited significantly higher FA in the body of the corpus callosum compared with the high Fagerström group and the nonsmokers. These results suggest that, among healthy adults, lower exposure to cigarette smoking is associated with increased microstructural integrity of the white matter compared with either no exposure or higher exposure. Additional studies are needed to further explore differences in white matter integrity between smokers and nonsmokers.
authors.affiliation: Department of Psychology, Behavioral Neuroscience, University of Missouri, St. Louis, MO 63121, USA. paulro@umsl.edu
authors.forename: Robert H
authors.initials: RH
authors.lastname: Paul
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Grieve
authors.forename: Raymond
authors.initials: R
authors.lastname: Niaura
authors.forename: Sean P
authors.initials: SP
authors.lastname: David
authors.forename: David H
authors.initials: DH
authors.lastname: Laidlaw
authors.forename: Ronald
authors.initials: R
authors.lastname: Cohen
authors.forename: Lawrence
authors.initials: L
authors.lastname: Sweet
authors.forename: George
authors.initials: G
authors.lastname: Taylor
authors.forename: Richard C
authors.initials: RC
authors.lastname: Clark
authors.forename: Sakire
authors.initials: S
authors.lastname: Pogun
authors.forename: Evian
authors.initials: E
authors.lastname: Gordon
mesh_terms: D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D002908:Chronic Disease; D003337:Corpus Callosum / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012016:Reference Values; D012907:Smoking / Q000473:pathology*