Abstract
Background and aims
Characterizing distinct quitting trajectories may inform tailored behavioral smoking cessation interventions. We identified the quitting trajectories and associated characteristics in Hong Kong Chinese smokers.
Methods
Data were from eight randomized controlled trials nested within the annual Smoking-free Community Campaign (‘Quit-to-Win’ Contest) from 2014 to 2021. The trials were two- or three-arm evaluating the effectiveness of behavioral smoking cessation interventions in 8300 adult daily smokers who were proactively recruited from communities across Hong Kong and followed-up at 1, 2, 3 and 6 months. Daily cigarette consumption was collected at baseline and follow-ups for identifying quitting trajectories by group-based trajectory modeling based on relative changes in cigarette consumption (vs. baseline) over four follow-up assessment points. Multinomial logistic regressions were used to yield relative risk ratios (RRRs) for the trajectories by baseline smoking-related characteristics, adjusting for sex, age, economic status and education attainment.
Results
Four quitting trajectories were identified, including quitters (4.6%), relapsers (6.8%), reducers (54.8%) and persistent smokers (33.8%). Compared with persistent smokers, smokers in the other 3 trajectories were associated with having previous quit attempts, higher intention to quit and perceived higher importance and confidence in quitting (all P < 0.05). Quitters [adjusted RRR (aRRR) = 0.59, 95% confidence interval (CI) = 0.62–1.00] and relapsers (aRRR = 0.75, 95% CI = 0.61–0.91) reported lower nicotine dependence vs. persistent smokers, whereas reducers showed higher nicotine dependence (aRRR = 1.39, 95% CI = 1.25–1.55) at baseline. Relapsers and reducers perceived higher difficulty of quitting (all P < 0.05). When compared with quitters, relapsers had higher intention to quit within 7 days (aRRR = 2.32, 95% CI = 1.64–3.28) and perceived higher importance (aRRR = 1.17, 95% CI = 1.09–1.25) and confidence (aRRR = 1.10, 95% CI = 1.04–1.17) in quitting, while reducers showed lower intention to quit within 7 days (aRRR = 0.59, 95% CI = 0.45–0.77) and perceived lower confidence in quitting (aRRR = 0.91, 95% CI = 0.86–0.95). Subgroup analysis of different interventions showed similar trajectory shapes and group probabilities.
Conclusions
Chinese smokers who joined behavioral smoking cessation trials in Hong Kong appear to have four quitting trajectories, each with associated characteristics, which may help predict the potential quitting trajectories and inform future interventions.