The correlation between FA levels throughout the whole corpus callosum and the amount of tobacco use (N = 16).

<p>There was a significant negative correlation between FA levels throughout the whole corpus callosum and the amount of tobacco use covariant age (cigarettes/day; R = − 0.580, <i>p</i> = 0.023). The number of spots was decreased from 16 to 13 because three spots represented the same data (three represented the FA level = 0.52 and N = 15, and two represented the FA level = 0.55 and N = 20; these spots are shown in gray spots).</p

Background of smokers and non-smokers.

<p>Abbreviation. AUDIT: Alcohol Use Disorders Identification Test; TDS: Tobacco Dependence Screener Scale; FTND: Fagerström Test for Nicotine Dependence; CO; carbon monoxide.</p><p>*Detailed information about the smoking-related clinical variables and the AUDIT scores of three subjects (N = 16) were not available. The mean AUDIT scores of the smokers (N = 16) was significantly higher than that of the nonsmokers (N = 18; smokers: 9.1±6.3; nonsmokers: 4.9±4.4; p = 0.022).</p

TBSS and tract-specific analysis results.

<p>The red voxels represent the areas where the fractional anisotropy (FA) levels of smokers were significantly reduced with respect to those of nonsmokers. Compared with nonsmokers, the smokers exhibited a significant decrease in FA throughout the whole corpus callosum.</p