This study was exploratory and was not designed to rigorously test specific components of Internet assistance for quitting smoking but rather to describe and compare the long-term effectiveness of currently available programs. It provides self-reported data on cessation status without verification. While the follow-up response rate was only 38%, previous studies with monetary incentives for Internet research participants yielded responses from only about half of the study participants [4
]. As Eysenbach [17
] has noted, research on this topic is inevitably flawed by attrition. The intent-to-treat standard for assessing quit rates as a proportion of enrolled rather than followed participants may bias research on Internet-based cessation services toward the null hypothesis of no treatment effect. Enrollment in an Internet service should be deliberately designed to make it easy for the user, but the impersonal nature of Internet enrollment also makes it possible for people to enroll without making any real commitments to what they have signed up to do. This feature probably also explains the generally observed difficulty with continuation rates in Internet assistance (eg, [5
]) and the low continuation rates observed here.
Although no significant differences were observed between the quit rates of different tailored, interactive sites in this 13-month follow-up, it is possible that differences were not detected because sample sizes in this study did not provide the statistical power for tests of differences of less than approximately 3% to 6% among the enrolled and followed groups, respectively. Among participants without an indicator of depression, the significantly different 13-month quit rates in the tailored, interactive sites and the targeted, relatively static site (13% vs 10% of enrolled and 32% vs 36% of followed participants) compare favorably with the long-term quit rates typically reported by telephone counseling interventions [1
No similarly long-term study of Internet quitting assistance has been previously reported, and, despite the unavoidable limitations of unvalidated self-reports of cessation and a high rate of loss to follow-up, this exploratory study allows some cautious conclusions. It shows that Internet assistance is attractive and cost-effective. In a relatively short time, more than 6000 users enrolled through the link posted on the regularly publicized ACS website. Service was provided with no costs other than those associated with establishment of the website linkages and the targeted, relatively static site posting. Approximately 4 days of programming at a cost of less than US $2000 allowed approximately 5000 additional users for scalable services from the five tailored, interactive service providers. This contrasts with the much larger cost of serving 1000 new clients with telephone counseling (approximately US $100,000).
Based on previous studies of telephone counseling showing lower cessation effects among clients with an indicator of depression than among those without [14
], it is not surprising to find a similar result in post hoc analyses of the data from this study. Studies that do demonstrate long-term intervention effects on cessation among depressed smokers involve much more intensive personal contact in individualized learning sessions (eg, [21
It was surprising to find that those who reported the depression indicator and were assigned to the tailored, interactive sites had, although not significantly, lower cessation rates than those assigned to the targeted, relatively static site. One major difference between the tailored, interactive sites and the targeted, relatively static site was the time that the participant must invest in the site. The tailored, interactive sites required the participant to spend time registering and providing the personal details that inform the tailoring, whereas the targeted, relatively static site was accessed without registration. The participant could link to the site and immediately read or download the materials for later reference. The greater effort required to participate in the interactive sites may have acted as a deterrent to quitting among depressed smokers.
Short-term results from the present study [9
] found that cessation rates were strongly related to the mean number of visits to the different sites. Those sites with the most visits tended to produce better short-term results. This finding was repeated in the post hoc analyses reported here, which also show a strong relationship between number of visits and long-term quitting success. Future studies should employ randomized experimental designs to rigorously examine the effectiveness of various discrete features of Internet assistance, such as outbound emails, chat rooms, and other ways of engaging users and providing support for the quitting process.
The possible influence of depression on the effectiveness of interactive Internet assistance requires further research with more complex indicators of depression to examine how they relate to specific processes and responses in Internet-assisted smoking cessation. In this study, about one in three participants reported an indicator of depression, which is lower than the one in two rate that we currently find among research participants receiving telephone counseling [15
]. However, this rate is still substantial, and we hope in further studies to identify ways to effectively provide everyone who seeks help via the ACS main website with services that can increase their odds of quitting.
The present study suggests that a high volume of use may be expected for Internet sites that offer useful assistance for smoking cessation. However, many persons seeking to quit smoking do not choose the Internet for assistance. The present study suggests that Internet-based cessation assistance may appeal to clients who are much more educated and presumably more comfortable with Internet communication than those who seek telephone-based assistance. Both modalities of service should be provided in comprehensive smoking cessation assistance programs.