Supporting data for PhD thesis "Innovations of the Youth Quitline for Improving Smoking Cessation among Youth Smokers in Hong Kong"

This thesis is based on a prospective cohort study in adolescents and young adults who use the HKU Youth Quitline service in Hong Kong, and a pilot RCT on EMA-based peer counselling for smoking cessation in a sample recruited from the Youth Quitline since May 2023.

Data were collected using structured questionnaire by peer counsellors via telephone interviews. The questionnaire includes questions on basic sociodemographic and smoking-related characteristics, including sex, age, marital status, employment status, and educational attainment, smoking status, age at smoking initiation and regular smoking, cigarette consumption per day, nicotine dependence assessed by the Fagerström Test for Nicotine Dependence (FTND), intention to quit, past quit attempts, self-efficacy (perceived importance, confidence, and difficulty of quitting), and withdrawal symptoms. The lifestyle factors (alcohol drinking habits, physical activity), depressive symptoms measured by the Center for Epidemiological Studies Depression (CES-D), and self-esteem were also collected. In addition, we also assessed the use of other tobacco products in past 30 days. In addition, the EMA study collected data on the mental states, smoking cues, and sleep status 4 times a day during each 1-week EMA wave for 2/3 waves.

The smoking cessation outcomes were assessed at 3-month and 6-month follow-up. Self-reported 7-day PPA was defined as not smoking during the past 7 days at follow ups. Those who reported no smoking in the past 7 days at 6-month follow-up were invited for biochemical validation test. The biochemically validated abstinence was confirmed by saliva cotinine level ≤ 10 ng/ml or a CO level in expired air ≤ 4 p.p.m. An incentive of HK$300 was given to those who passed the test. Smoking reduction was defined as cigarette consumption reduction by at least 50% at 6-month follow-up compared to baseline ≥50%.