Procedure
Cancer
RECRUITMENT, CANCER
After recruitment, participants were required to complete the baseline questionnaire and register through WeChat. We first classified our participants into two groups: low nicotine dependence; or moderate and high nicotine dependence. Then we used a simple randomization method to assign participants to the intervention group or control group within each nicotine dependence group.All participants in the two groups were instructed to attend face-to-face follow-ups with research staff at 1 month, 3 months and 6 months after randomization. At each follow-up visit for all participants, we recorded smoking status, score on the protection motivation theory components and quitting intention.Participants who were allocated to the intervention group received the intervention programme with personalized text messages, as described above. The information that participants received from the WeChat message bank varied depending on the evaluation of their motivation to quit and their self-reported smoking status. On day 0, all the intervention participants received the same message about registration in the programme and completed the first evaluation via the chat application (Participants in the control group received a set of messages developed by the United States National Cancer Institute, which have been adapted to be culturally appropriate for a Chinese audience.Both groups received 1–2 messages a day for 3 months after randomization.