05, OR=2.18 (95% CI=1.04�C4.59). In GLM analyses of the continuous withdrawal slope, there was neither a significant haplotype effect nor a significant diplotype effect across age-at-onset conditions. We examined the possible effect of bupropion treatment on the relationship between haplotype and withdrawal severity. First, bupropion was entered in a logistic regression selleck inhibitor model along with haplotype coding and a haplotype �� bupropion interaction with dichotomous withdrawal as the dependent variable. No significant interaction effects were observed for either the HA versus HC, p=.23, or the HA versus HB, p=.40, contrast. In a second model, the interaction term was dropped but bupropion was retained as a covariate. In this second test, the HA versus HC contrast was significant, p=.03, OR=1.

56 (95% CI=1.04�C2.33). The bupropion effect did not reach nominal significance, p=.08, OR=0.76 (95% CI=0.56�C1.03). Thus, the protective effect of HA relative to HC on withdrawal severity was independent of any effect bupropion may have had on withdrawal severity. Smoking cessation In a logistic regression analysis in which the dependent variable was relapse versus no relapse over the first 90 days postquit, we found no haplotype �� age-at-onset interaction. Thus, further tests of smoking cessation were made across the combined age-at-onset conditions. As shown in Figure 2 and Table 3, HA was associated with a higher relapse rate than HC, and the HA versus HB contrast approached significance. Diplotype analyses, also shown in Figure 2, indicated that diplotype AA had a higher 90-day relapse rate than every other diplotype, p��s=.

006�C.03, OR��s<0.45 (95% CI��s=0.15�C0.93). Abstinence rates, expressed as Kaplan�CMeier survival functions, over the first 90 days postquit are shown as a function of haplotype and diplotype in Figure 4. A survival analysis revealed a significant haplotype effect, ��2(2, n=767)=7.45, p=.02. Pairwise comparisons were significant for both the HA versus HB test, ��2(1, n=629)=5.41, p=.02, and the HA versus HC test, ��2(1, n=638)=4.58, p<.04. The HB versus HC comparison was not significant. We also found a significant diplotype effect across all five diplotypes, ��2(4, n=629)=5.41, p=.02. Pairwise comparisons indicated that the relapse rate was higher for diplotype AA than for each of the other four diplotypes, p��s=.005�C.03 (see Figure 4).

Entering drug (bupropion vs. placebo) as a covariate in the haplotype or diplotype survival analyses did not alter any of these findings nor were there any significant interaction effects with drug. Figure 4. Abstinence following a smoking cessation trial by haplotype (top, n=767) and diplotype (bottom, n=356). Abstinence is shown as the Kaplan�CMeier probability of remaining abstinent for the first 90 days Drug_discovery postquit. …