Effect of mobile phone-based interventions on smoking cessation among workplace smokers with mental health symptoms during the COVID-19 pandemic

Abstract

Background: Despite the global and local (Hong Kong) decline in smoking rate in the past several decades, smoking rate remains disproportionately high among people with mental health problems. This trend has worsened during the COVID-19 pandemic, a period marked by a mental health crisis and complex smoking behaviors. The extensive use of mobile phones offers a chance to provide psychobehavioral support remotely. The thesis aimed to evaluate the effect of mobile phone-based interventions for smokers with mental symptoms in the workplace amid the pandemic. Methods: A population-based survey was conducted to investigate changes in smoking behavior during the pandemic and its relationship with the perceived increased risk of COVID-19 infection from smoking. Subsequently, a secondary analysis compared smoking cessation outcomes between smokers with mental symptoms and those without, among people who received the usual workplace smoking cessation service during the pandemic. In a pragmatic randomized controlled trial, 300 daily smokers with stress (Perceived Stress Scale-4 ≥ 6), anxiety (General Anxiety Disorder-2 ≥3) or depressive symptoms (Patient Health Questionnaire-2 ≥3) from 65 companies were recruited. The effect of a personalized chat-based smoking cessation intervention paired with psychological support on abstinence was evaluated. The intervention group received 20 instant messages and chat-based support over 3 months, while the control group received 6 general health messages. Both groups were provided with a 1-hour health talk and self-help booklet at baseline, brief phone advice during follow-ups, and nicotine replacement therapy for continuing smokers at 6 months. The primary outcome measured was self-reported 7-day point prevalence abstinence (PPA) at 6 months. Secondary outcomes included PPA at 1, 3, 9, and 12 months, changes in mental health, and engagement with the intervention. Results: During the COVID-19 pandemic, a higher percentage of smokers reduced smoking on the street than at home (46.1% vs. 8.7%), with no significant association with perceived increased risk of COVID-19 infection due to smoking (adjusted RR=1.13, P=0.09). Among smokers who received usual smoking cessation services amid the pandemic, those with mental symptoms reported lower PPA at 9 (13.4% vs. 21.2%, adjusted OR=0.36, 95% CI 0.16 to 0.78, P<0.05) and 12 months (17.2% vs. 25.9%, 0.42, 0.20 to 0.87, P<0.05) than those without mental symptoms. In the main trial, 300 smokers with mental symptoms (84.3% male, 57.3% aged 30 to 49 years) were randomly assigned to the intervention (n=144) and control (n=156) groups. A significant difference in 7-day PPA between intervention and control groups at 6 months (16.0% vs. 13.5%, OR=1.22, 95% CI 0.64 to 2.32) was observed. At 12 months, there was weak evidence of an intervention benefit (21.5% vs. 13.5%, OR=1.76, 95% CI 0.96 to 3.24), which became statistically significant after adjusting for baseline factors (adjusted OR=2.61, 95% CI 1.22 to 5.58, P=0.01). Conclusions: This thesis found that usual smoking cessation services are less effective for smokers with mental symptoms compared to those without. While a personalized chat-based intervention did not achieve the expected cessation effect in this vulnerable group, the growing difference between groups over time suggests a potential long-term benefit.