This study shows that it is possible to conduct a smoking cessation RCT via the Internet with an international sample of English- and Spanish-speaking smokers. The overall 12-month 7-day abstinence rates were 30.2% based on participants with follow-up data and 20.6% when those with missing data were assumed to be smoking. Because such public health smoking cessation interventions can reach a geographically wider audience of smokers than traditional face-to-face or pharmacological interventions, they should be developed and tested in additional languages.
Our results show that an empirically supported print intervention adapted to the Web and provided to Spanish- and English-speaking smokers throughout the world with or without additional elements yielded good results. English speakers quit at significantly higher rates at 1-, 3-, and 6-month follow-ups, but Spanish speakers caught up by the 12-month follow-up. We are intrigued by this increase in abstinence rates at 1 year for Spanish speakers (which underscores the advisability of follow-up assessments beyond 6 months). We speculate that local norms for smoking may have helped English speakers quit sooner but that the follow-up E-mails throughout the year may have reminded participants of their initial intention to quit and may have helped them recommit to quitting.
On hindsight, a major limitation of this study is the lack of an adequate control condition. We conceptualized the Guía
alone as a control condition because earlier studies (e.g., Muñoz et al., 2006
) had yielded lower rates for the Guía
in one-condition studies. However, we had not compared the Guía
alone with the current study’s Conditions 2 and 3. Our current results show that this static condition can be as efficacious as more interactive conditions. There is no evidence of increased abstinence rates with additional elements in either language, even though utilization of the interactive aspects of the site was significantly higher for the three conditions that added elements to the static condition, and utilization of the tools available to all participants was significantly related to abstinence.
We have considered the possibility that the lack of differences among conditions is due to the requirement to log daily cigarettes three times before randomization. This may have limited participants to those motivated enough to quit at about the same rate (20%), no matter what the intervention received. We examined whether this requirement might have resulted in a large proportion of participants becoming abstinent before randomization. We found that 6.8% indicated smoking no cigarettes the day they were randomized (i.e., the third day they logged cigarettes). This rate is similar to the quit rates of smokers motivated enough to join face-to-face smoking cessation trials using the patch, who report 6-month placebo patch rates of only 5%–9% (Fiore et al., 1994
; Schroeder, 2005
). Thus, high motivation does not yield 20% quit rates even in smokers motivated enough to physically travel to clinical research sites and receive brief counseling interventions. In terms of Internet studies, a wait-list control condition (Swartz et al., 2006
) yielded a 5% quit rate at 90 days. This is comparable to the nicotine patch placebo control rates above and does not approximate the 20% abstinence rate found in the present study. Finally, the missing = smoking cessation rates reported by Spanish-speaking smokers in this study at 1, 3, 6, and 12 months were 13%, 14.2%, 12.4%, and 20.2%, compared with 20.8%, 18.0%, 16.8%, and 21.0% for the English speakers. Thus, smoking cessation rates provided by our participants were not uniform across the board. As in our earlier article (Muñoz et al., 2006
), we are left with the possibility that adding more interactive content is not necessarily better than an effective, though static, smoking cessation guide.
Abstinence rates observed were very different from those used in our power calculations and may have underpowered the trial, thus constraining our ability to find differences among the conditions. Our results are similar to those of the American Cancer Society’s QuitLink study (Pike et al., 2007
). This study compared six interactive sites with a static site that provided a brochure online. The study sample was composed of 6,451 English-speaking adult U.S. smokers. Follow-up rates were 54% at 4 months and 44% at 7 months. Prolonged intent-to-treat abstinence rates were not significantly different and, on average, 11.0% and 9.9% for the interactive sites at 4 and 7 months, compared with 10.9% and 9.5% for the static site. Thirteen-month rates were, again, not significant (Rabius et al., 2008
). The QuitLink study suggests that both tailored Web interventions and an online brochure are moderately efficacious. A recent study by McKay et al. (2008)
also showed no significant differences between an active intervention and an attention placebo. The field needs to determine whether a Web site (static or interactive) yields higher abstinence rates than not having access to any site or whether participants who join online smoking cessation trials are so motivated that they all quit at about the same rates as long as the Internet interventions contain quality, empirically based information. Until this issue has been adequately examined, Web-assisted tobacco intervention trials should include no-intervention delayed conditions. Follow-up surveys should inquire whether control participants used other smoking cessation methods, including other Web sites, of course.
Attrition at follow-ups was reduced by (a) requiring that participants return to the site three times within a week prior to randomization, (b) sending surface mail letters at randomization and prior to each follow-up period, (c) sending E-mails with links to the follow-up surveys, and (d) calling participants on the phone up to 10 times if they did not respond to the E-mails. With this approach, we were able to contact 692 of the 1,000 participants in the trial (69.2%) at the 12-month follow-up, of whom 206 out of 682 who answered the 7-day abstinence question reported having quit.
The overall findings for each condition from this randomized trial are similar to our earlier findings (Muñoz et al., 2006
). For example, for Study 4 in the 2006 report, which was done in Spanish, the Guía
+ ITEMs condition 12-month missing = smoking rate was 22.6%, compared with 17.3% for Spanish speakers in the current study, and the Guía
+ ITEMs + MM condition was 20.4%, compared with 19.8% for Spanish speakers in the current study. The new Guía
+ ITEMs + MM + VG condition (Condition 4 in the current study) yielded 12-month missing = smoking abstinence rates of 21.3% in English and 24.2% in Spanish. These rates reinforce the potential benefit of making these sites (http://www.stopsmoking.ucsf.edu
) available to smokers worldwide at no charge to users, to create similar sites in other languages, and to invite national and international health organizations to publicize these sites and make them accessible to smokers interested in quitting. If we can help 20% of those who come to such Internet sites to stop smoking at 1 year, these sites could have substantial impact on reducing the suffering and death caused by this major source of morbidity and mortality worldwide.