Alternative tobacco product use in Hong Kong adolescents : use patterns, environmental correlates, and associations with respiratory symptoms

Abstract

Cigarette use prevalence has started to decrease in many countries and regions, but alternative tobacco products (ATPs), such as electronic cigarettes (ECs), heated tobacco products (HTPs), and waterpipe, became increasingly popular, especially in youth, threatening tobacco denormalisation. This thesis examined 1) the prevalence and use patterns, 2) environmental correlates, 3) gateway effects, and 4) respiratory health risks of ATP use, and 5) the influence of the COVID-19 pandemic on ATP use, in Hong Kong adolescents. Quantitative data were from a cross-sectional tobacco survey among 27159 secondary school students in 2016/17 and 34063 in 2018/19. Qualitative data were from a study of 32 in-depth interviews on tobacco use during the COVID-19 pandemic in 2021. Multivariable regression models were used to assess the associations of ATP use with sociodemographic factors, exposure to tobacco advertising, subsequent cigarette use, and persistent respiratory symptoms. Inductive analysis was used to examine perceived risks of COVID-19 in relation to tobacco use, and the influence of the COVID-19 pandemic on tobacco use. The current use prevalence of any ATPs (3.0%) was similar to that of cigarettes (3.2%). Over half the ever users of HTPs, ECs, and waterpipe were currently using them. Ever use, current use, and current use in ever users of ECs, HTPs, and waterpipe showed J-shaped associations with perceived family affluence (P values <0.05), being lowest in the middle groups and highest in the richest families. Susceptibility to EC use was associated with exposure to EC advertising in the past 30 days (adjusted odds ratio [AOR] 2.00, 95% confidence interval [CI] 1.56–2.48), and 16.6% of the association was mediated through tolerant attitudes towards ECs and the tobacco industry. Use of waterpipe (adjusted prevalence ratio [APR] 2.43, 95% CI 2.05–2.88), ECs (1.95, 1.75–2.16), or HTPs (3.44, 2.92–4.05) was associated with subsequent cigarette use initiation versus no ATP use. In addition, use of HTPs (versus no HTP use) and nicotine products (versus nicotine-free products) was associated with progression to monthly and weekly cigarette use, progression within 1 year, and current cigarette use. Persistent respiratory symptoms were independently associated with former (APR 1.30, 95% CI 1.06–1.59) and current (1.59, 1.23–2.06) HTP use. The associations were significant in never and former cigarette users, but not in current cigarette users. Compared with exclusive ever cigarette use, exclusive ever HTP use and ever dual use of both products were associated with persistent respiratory symptoms. Cigarette use was perceived to increase the susceptibility and vulnerability to COVID-19, but EC use was perceived as less hazardous. Students reduced or intended to reduce cigarette use under the COVID-19 pandemic, but covert EC use at home was unaffected. In conclusion, ATP use in Hong Kong adolescents had become as common as cigarette use. It was associated with subsequent cigarette use, and unaffected by the COVID-19 pandemic. Nicotine-containing ATPs and exposure to tobacco advertising could facilitate ATP use. Stringent regulations and thorough implementation are needed to prevent tobacco epidemic in adolescents. Education programmes should also be enhanced to combat misperceptions.