This study supports the feasibility of engaging depressed women in an exercise intervention for smoking cessation. Despite study demands (e.g., numerous assessments including treadmill test, time-intensive clinical interviews, weekly meetings, and multiple behavior changes including use of nicotine patch and exercise) and the additional challenges of study participation while depressed, 65% of participants completed the 10 weeks of treatment (20 of 30 health education participants; 19 of 30 exercise counseling participants). This intervention adherence rate approximates that of studies examining exercise intervention session participation in nondepressed populations (e.g., 72.1% of smoking cessation sessions and 70.5% of weekly onsite supervised exercise sessions; Marcus et al., 2005
). Our participant adherence to treatment rate is fairly impressive given that participants enrolled in this study were quite depressed, with depression scores in the range of clinical depression, and most receiving active treatment (medication and/or therapy) for their depression. Previous research has shown that adherence to health behavior is affected by depression (Wing et al., 2002
) and that higher depression scores are associated with lower self-efficacy for exercise and more tendency to get off track and feel like a failure (Vickers, Nies, Patten, Dierkhising, & Smith, 2006
). Despite the additional challenges of behavior change for depressed people, exercise counseling participants in this study were able to increase significantly their exercise frequency and exercise stage of change while attempting to quit smoking.
The exercise intervention was not associated with improved smoking abstinence rates compared with the contact control condition. The smoking abstinence rate at follow-up was low (7% using intention-to-treat analysis with 48% missing data), despite the fact that the participants had received a state-of-the-art treatment for smoking cessation (pharmacotherapy + behavioral counseling) (Fiore et al., 2008
). However, results of a recent meta-analysis of controlled nicotine patch trials indicated that the rates of quitting smoking due to nicotine patch versus placebo are lower in women than in men (Perkins & Scott, 2008
). Thus, future studies may benefit from supplementing nicotine patch treatment or using an alternative smoking cessation medication. Further, Ussher et al. (2003)
found that an exercise counseling intervention similar to that used in the present study did not increase rates of smoking cessation compared with a control condition, and it was concluded that the exercise counseling did not increase levels of physical activity sufficiently. A higher intensity of exercise may have improved the smoking abstinence rates. Marcus et al. (1999
) previously found that vigorous intensity but not moderate intensity exercise was superior to a health education contact control condition for treating smokers. Further, lower rates of exercise adherence were found for moderate intensity than for vigorous intensity exercise. In the vigorous intensity trial, participants completed a majority of their exercise at a supervised gym-based setting, whereas in the moderate intensity trial, the majority of exercise was completed at home. Further research is needed to evaluate the efficacy of vigorous intensity versus moderate intensity exercise and gym versus home-based exercise formats for depressed women attempting smoking cessation.
Future studies with depressed women smokers should limit participant burden and increase within-treatment social support. Depressive symptoms impacted almost every aspect of participation in this study. Many participants reported feeling burdened by study paperwork and assessments, and many participants wished to talk about psychosocial stressors and other depression-related content during intervention sessions. Exercise counseling participants often focused on the barriers to exercise and were quite self-critical when not meeting their exercise goals. Consequently, study staff must be trained to balance the empathy and support necessary to help depressed participants complete a demanding research study with adherence to assessments and intervention protocol. Future studies should carefully plan for and monitor treatment fidelity (Bellg et al., 2004
; Waltz, Addis, Koerner, & Jacobson, 1993
The majority of study participants across the two groups reported regret that the study was ending, as they so valued the social support associated with the weekly study visits. For instance, a group walking program or other exercise intervention that involves support may be particularly appealing to depressed women. Qualitative research methods may be useful in elucidating exercise and smoking cessation intervention preferences among depressed women who smoke.
There are several limitations to this pilot feasibility study. The study was sufficiently large for a feasibility or pilot study (Lancaster, Dodd, & Williamson, 2004
), but it was relatively small compared with previous exercise intervention trials for smokers (e.g., Marcus et al., 2005
). The sample was predominately White women with postsecondary education, which limits generalizability to the general population of smokers. Although we assessed changes in depression treatment (medication/therapy), we did not assess the impact of this on study outcomes, which would be necessary in future efficacy trials. Alternatively, future studies could attempt to recruit depressed smokers not currently on antidepressant medication or standardize medication as part of the trial. Most participants in our study had depression scores in the moderate to severe range, and exercise interventions may be more effective for women with milder depression. Many women decided not to participate in the study and, of those enrolled and randomized, nearly half dropped out by Week 24 follow-up, despite study staff's best efforts to be accommodating with schedule conflicts, to call and encourage those who missed a session, and to be supportive following lapses. The demands of study assessments (treadmill test, structured interviews, and daily activity records), psychosocial stressors, and ambivalence about quitting smoking all contributed to nonparticipation and dropout. Consequently, those that remained in the study likely represent a more motivated group and do not fully represent the general population of depressed smokers. Because attrition results in missing data, larger studies with depressed smokers should utilize best methods for handling missing data (Fielding, Maclennan, Cook, & Ramsay, 2008
; Wood, White, & Thompson, 2004
Women with depression represent a difficult-to-treat subgroup of smokers. Our participants had clinical levels of depression and a significant smoking history with previous quit attempts. Our study suggests that an exercise intervention is feasible among depressed female smokers and is associated with increased exercise. Additional research is needed to identify effective strategies for assisting depressed women in quitting smoking and maintaining their abstinence, perhaps with higher intensity exercise, supervised exercise, group-based support, and relapse prevention strategies for both exercise and smoking behavior.