This research presents abstinence rates for three vulnerable populations from two independent cessation trials each of which evaluated the same five pharmacotherapy treatments. The results suggest that women, Blacks, and smokers with less than a high school education are less likely to quit smoking successfully than are men, Whites, and smokers with more than a high school education, respectively, despite receiving efficacious pharmacotherapy and despite there being no group differences in amount of medication used. These results support previous findings that these populations have disproportionate difficulty maintaining abstinence. Our combined model also showed that each of these factors—gender, race, and education—are uniquely related to quitting success in the short-term. However, only gender was a significant predictor of long-term abstinence. It may be that women are particularly vulnerable to long-term or posttreatment relapse. Identifying the nature of this vulnerability is an important area for further research so that effective treatments, such as long-term pharmacotherapy, can be developed and/or applied appropriately.
While these groups had lower abstinence rates across the board, one notable finding was that women and <HS smokers appeared to benefit specifically from combination pharmacotherapy, relative to monotherapy. This finding is promising for treating tobacco dependence in women and <HS smokers, but overall this research underscores the need to develop new treatments—including novel psychosocial interventions—that address cessation difficulties among women, Blacks, and smokers with less education.
Our results did not support the hypothesis that women are particularly responsive to bupropion. Rather, women appeared to be most responsive to combination pharmacotherapy. We examined gender differences in abstinence rates for each treatment condition and found that the difference between men and women was smallest for the patch condition in the Efficacy sample and in the patch + lozenge condition in the Effectiveness sample. In the combined sample, there was actually an opposite effect such that men who received bupropion combined with lozenge had significantly higher 8-week abstinence rates than did women in that condition. The overall findings suggest that women indeed benefit from NRT, but women may need higher doses than previously thought as they had the highest abstinence rates in the combination nicotine patch + lozenge condition. This finding needs to be replicated and explored as it contradicts logic that women should require less nicotine replacement since they smoke fewer cigarettes per day than men, and therefore, are less dependent than men. However, these findings do fit with research showing that women have significantly higher rates of nicotine metabolism than do men, particularly when using oral contraceptives (Benowitz, Lessov-Schlaggar, Swan, & Jacob, 2006
); therefore, women require more nicotine to maintain a steady state of nicotine in the blood.
With respect to race, Blacks were less likely to quit, overall, and did not appear particularly responsive to combination therapy. This may be related to the finding that Black smokers appear to have slower rates of nicotine metabolism than do White smokers (Benowitz et al., 1999
; Perez-Stable, Herrera, Jacob, & Benowitz, 1998
) and therefore they do not receive significant benefit from extra nicotine. However, there were some treatment conditions that may be promising, although these findings were not consistent across the samples. For instance, in the Efficacy sample, the nicotine lozenge and the nicotine patch + lozenge conditions had the highest abstinence rates and the bupropion and bupropion + lozenge condition produced the lowest abstinence rates. It may be that Black smokers, 90.6% of whom reported smoking menthol cigarettes (compared with 35.9% of White smokers), found the mint-flavored lozenges more palatable or reinforcing (although the lozenge in the bupropion + lozenge condition was not particularly effective). The 90.6% rate of menthol cigarette use is higher than has been previously reported among Blacks (Giovino et al., 2004
; Okuyemi, Faseru, Sanderson Cox, Bronars, & Ahluwalia, 2007
). Conversely, in the Effectiveness sample among Black smokers, bupropion + lozenge produced the highest abstinence rates and the lozenge alone produced the lowest abstinence rates. Future research is needed to determine optimal pharmacotherapy for Black smokers and smokers of menthol cigarettes.
This research is consistent with other findings that low SES smokers are less likely to quit (Giskes et al., 2006
; Velicer et al., 2007
). However, combination pharmacotherapy for smokers with less than a high school education more than doubled their abstinence rates relative to monotherapies. In fact, combination pharmacotherapy appeared to minimize the differences between educational attainment groups. This is consistent with the finding that <HS smokers smoked at the highest rates of the three education groups, suggesting that <HS smokers may be more dependent and therefore less likely to quit and perhaps more likely to benefit from greater levels of nicotine replacement. However, additional analyses (not shown) revealed that, after controlling for dependence, education continued to predict 8-week, but not 6-month, outcome. This suggests that the difference in abstinence rates by education, at least early in the quit attempt, is not solely due to higher levels of dependence. While these results suggest that smokers with low educational attainment should receive combination pharmacotherapy, economically disadvantaged smokers may need assistance to pay for the more expensive combination therapy for this pharmacological treatment to have a true public health impact.
This study’s findings need to be interpreted within the context of certain limitations. First, this is a secondary analysis of two studies—one was a longitudinal study, which may have selected for participants with greater motivation to quit than smokers in the general population, and the other occurred in a primary care setting and offered limited psychosocial counseling. However, there was only one Treatment × Study interaction, suggesting that the treatments performed similarly across the two studies although combination pharmacotherapy appeared to be particularly advantageous in the Effectiveness context, relative to the Efficacy context. Second, despite having two large samples, when the samples were broken down into subgroups (e.g., Black smokers, smokers with less than a high school education) and then further divided into the five treatment conditions, the individual group sample sizes were small (e.g., 36 <HS smokers received patch + lozenge; 58 Black smokers received bupropion alone). Therefore, the stability of the estimates is reduced and the power to detect smaller effects may have been compromised.