Black and white participants who utilized AA had higher 30-day abstinence rates in comparison to their non-AA utilizing counterparts (Figure 2). Among those who did not attend AA, rates of abstinence were consistently higher for blacks than whites. A significant interaction between race and AA utilization on 30-day abstinence over seven years emerged in the GEE model (Figure 3; z-statistic on interaction term: −2.81, p-value = 0.005). Although AA utilization was significantly related to alcohol abstinence in both racial groups, the relationship was weaker for black participants compared to white participants (OR: 2.21, 95% CI: 1.5–3.2, vs. OR: 4.03, 95% CI: 3.20–5.07, respectively). However, results from the interaction model including all covariates showed that among those who attended AA there was not a significant racial difference in the odds of abstinence between black as compared to white participants (OR: 0.77, 95% CI: 0.54–1.09) (Figure 3). By contrast, among people who did not attend AA, black participants had over one and a third times the odds of abstinence compared to white participants (OR: 1.39, 95% CI: 1.01–1.93). When analyses were repeated to include any substance use treatment utilization at baseline or prior, similar patterns emerged.
