American Cancer Society's QuitLink: randomized trial of Internet assistance.

Eligible smokers (N = 6,451) visiting the American Cancer Society's Internet site offering cessation assistance were, with informed consent, randomized to receive access either to a static Internet site with quitting advice or to one of five interactive sites provided by cooperating research partners. Three-month follow-up surveys were conducted via online survey with E-mail prompts, or telephone calls, to assess quitting success; 54% of participants provided follow-up data. Results showed no significant overall difference in cessation rates among participants assigned to the interactive or static sites. We found large differences in the utilization of the five interactive sites. When sites were grouped by level of use, a significantly higher reported 3-month cessation rate was observed among participants assigned to the more highly utilized sites than among those assigned to the less utilized sites (12.2% vs. 10.2% of all randomized participants, 26.0% vs. 22.1% of followed participants). These findings show that interactive Internet sites yielding high levels of utilization can increase quitting success among smokers seeking assistance via the Internet.