The results indicate that self-selected quit dates in the follicular phase are associated with a shorter time to relapse as compared to self-selected quit dates in the luteal phase. Our results also indicate that women are more likely to self-select a quit attempt during the follicular phase compared to the luteal phase. Further, the majority of women relapsed within the phase of their self-selected quit attempt but overall women were more likely to relapse to smoking during the follicular phase compared to the luteal phase. In sum, the follicular phase appears to be associated with poorer smoking cessation outcomes in this study sample.
The influence of repeat quit patterns versus effect of ovarian hormones on self-selected second quit date and subsequent relapse is difficult to differentiate. However, it is of note that phase of relapse of second self-selected quit is consistent with our previous publication (Allen et al, 2008
) on phase of relapse for randomized first quit. That is, relapse was greatest during the follicular phase compared to the luteal phase whether women were randomized to a quit phase or self-selected a quit phase. In our previous publication we discussed that the higher risk for relapse observed in the follicular phase was possibly related to ovarian hormone influence (Allen et al, 2008
). For example, estrogen may enhance subjective mood response to nicotine, the effect of progesterone may attenuate the physiological and subjective effects of nicotine (Sofuoglu et al, 2001
), there may be possible alteration of ovarian hormones on nicotine metabolism (Benowitz et al, 2006
), or there may be a combination of these factors in play. Although the clinical significance of these observed cycle phase differences remains unknown, the results do suggest that ovarian hormones may play a role.
Our results are in contrast to recent studies of smoking cessation and menstrual phase that have used pharmacotherapy. Franklin et al (2008)
conducted a retrospective analysis of women on nicotine replacement and found that relapse occurred more frequently when they quit in the luteal phase as compared to the follicular phase. Similarly, Carpenter et al (2008)
conducted a small prospective study of women on nicotine replacement. When measuring point prevalence abstinence two weeks after quit date, they observed that abstinence rates were higher in the follicular group compared to the luteal group. It is possible that the nicotine patch has a moderating influence on the menstrual phase effects. For instance, amelioration of withdrawal symptoms may result in less slips and therefore less reinforcement of smoking during the estrogen dominant follicular phase, whereas in the luteal phase the premenstrual symptoms albeit ameliorated by the nicotine patch (Allen et al, 2000
) still may result in more slips resulting in relapse. Or perhaps increased estrogen leads to a more positive response to NRT. Future studies are needed to address the mechanism of these effects.
Our study showed that 75.8% of study participants who relapsed from their initial quit attempt made a second quit attempt approximately four days after their first relapse, on average. Prior studies show despite the fact that 65 to 95% of quit attempts end in failure (Pierce & Gilpin, 2003
; Yudkin et al, 2003
), large numbers of smokers are interested in quitting again. One study showed that 65% want to make a repeat quit attempt within 30 days consistent across sociodemographic subgroups (Fu et al, 2006
). Another study (Joseph et al, 2004
) found in a survey of relapsed smokers, that 98% expressed interest in quitting and 50% were ready to quit immediately. Despite this high interest in quitting, it is notable that 86.2% of study participants relapsed to smoking after their second quit attempt. Research indicates that lapse to smoking is a significant predictor of eventual relapse (Kenford et al, 1994
). Relapse after second quit attempt was, on average, no greater than three days. Studies (Hughes et al, 2004
) show that most relapse occurs early and the majority of smokers relapse within eight days.
The strengths of this study include its prospective nature and building on the initial quit attempt results (Allen, et al 2008
) by evaluating the second self-selected quit attempts and relapse with regard to the menstrual cycle. This study also has some limitations. First, smoking status, although confirmed biochemically at clinic visits, was based on self-report and may be misreported on days study participants did not attend clinic visits. Second, we had a relatively large number of women who prematurely withdrawal from the study. Those who prematurely withdrew from the study showed signs of greater nicotine dependence. It is unknown how the level of nicotine dependence may influence the impact of menstrual phase on smoking outcomes. Furthermore, it is difficult to differentiate between phase effect and the function of time in the quit-relapse process. Thus our ability to make inferences regarding the causality of the menstrual cycle on our observed quit-relapse patterns is limited. More research is needed to define the quit-relapse patterns, and the influence of ovarian hormones,
In conclusion, our results suggest that the patterns of second self-selected quit attempts and relapse may be influenced by the menstrual cycle. This confirms our earlier work indicating women who quit in the follicular phase had less favorable outcomes. More research is needed to investigate how this relationship may be altered during smoking cessation attempts assisted by pharmacotherapy.