Distribution characteristics of all variables were examined. Only participants with complete data (including a complete ImpSS scale) were included in analyses. Also, baseline demographic data was evaluated for differences between those with complete data and those without complete data using t-tests for parametric data and Mann-Whitney U tests for nonparametric data. Primary analyses were conducted in four parts to evaluate the relationships between impulsive sensation seeking, parental history of alcohol problems and current use of alcohol and/or tobacco. First, the relationships of impulsive sensation seeking and the alcohol use variables and the concomitant alcohol-tobacco use variable were evaluated using univariate general linear model (GLM) analyses. To illustrate group differences in impulsive sensation seeking based on frequency of alcohol use, Bonferonni-corrected post hoc comparisons were used. Second, the relationships of parental alcohol problems and the alcohol use variables and the concomitant alcohol-tobacco use variable were tested using regression models. For the past month binge use variable, a logistic regression was performed; for the frequency of past month alcohol use and the concomitant alcohol-tobacco use variable, multinomial regressions were performed.
