Finally, having a biological parent with a history of an alcohol problem remained associated with past month concomitant alcohol-tobacco use after controlling for ImpSS score. Adolescents with a biological parent with an alcohol problem use history were more likely to have used tobacco only (OR = 4.24, 95%CI = 2.59–6.96), alcohol only (OR = 1.96, 95%CI = 1.53–2.52), or used both substances in the past month (OR = 3.57, 95%CI = 2.71–4.70), when compared to non-users. Controlling for ImpSS score only slightly altered the odds ratio for use of both alcohol and tobacco (controlling for ImpSS: 3.57, not controlling: 3.96), alcohol use only (controlling for ImpSS: 1.96, not controlling: 2.10), and tobacco use only (controlling for ImpSS: 4.24, not controlling: 4.58). As with the above analyses, the confidence intervals between the controlled and non-controlled analyses overlapped, suggesting no difference in outcomes. Data from the mediational analyses are summarized in Table 3.
