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.

Influence of cigarette smoking on white matter in patients with clinically isolated syndrome as detected by diffusion tensor imaging

“…The nicotine-induced cytotoxic swelling suggested by Gazdzinski et al (22) and proinflammatory effects of cigarette smoke on tissue as shown by elevated peripheral leukocytes, and recruitment of polymorphonuclear cells, monocytes, macrophages, and increased fibrinogen may be partly responsible for cellular edema and reduced MD levels in the H S of the current study (23). Some recent studies have hypothesized on the neurotropic and promyelinating effects of smoking and have found higher FA in brain regions such as the prefrontal WM, cingulum, and corpus callosum in smokers compared with nonsmokers (9,24). Yet, another study on heavy smokers reported decreased FA in the anterior corpus callosum (25).…”

“…The variable degrees of addiction of smoking in the participants might be one important factor in these contradictory research findings. Although limited dependence and exposure to nicotine revealed no significant change, heavy smoking exposure showed marked FA reductions in WM (9,24). Whether FA or MD is more sensitive and an earlier measure of WM disintegrity remains controversial in the literature (26,27).…”

“…Changes in the NAWM may also be responsible for the clinicoradiologic discrepancy observed in many patients (6). In addition, several MRI studies have shown significantly altered FA measures in specific brain regions in healthy smoker individuals (9,10). Although a number of studies have investigated the impact of smoking on patients with MS (4,11), to the best of our knowledge, no study has studied the influence of smoking on the WM in patients with CIS using DTI.…”

Vasogenic cerebral edema associated with the disability in activities of daily living in patients with chronic obstructive pulmonary disease

“…(2011) revealed a reduction in the microstructural integrity of the cerebral WM in cigarette smokers. Changes in DTI findings related to smoking behavior have been demonstrated in multiple regions, including the corpus callosum, internal capsule, and prefrontal WM at multiple levels (Hudkins, O'Neill, Tobias, Bartzokis, & London, 2012; Paul et al., 2008; Zhang, Stein, & Hong, 2010). In our study, after controlling for the number of pack years of smoking, there was no observable group difference in the ADC in the posterior corpus callosum.…”

Assessment of the effect of cigarette smoking on regional brain volumes and lesion load in patients with clinically isolated syndrome

“…Nicotine has been held responsible for the majority of the detrimental effects of smoking on the CNS [6][7][8]. It acts as an agonist within the cholinergic neurotransmitter system and nicotinic receptors are widely distributed within the CNS with the highest density in the thalami [6,9,10].…”