Impact of mandatory masking amid the COVID-19 pandemic on outdoor smoking: an interrupted time-series analysis of a 33-month unobtrusive observational study.

Background: Mask-wearing in outdoor public places in Hong Kong was mandated on 29 July 2020, amid the COVID-19 pandemic. We aimed to evaluate the impact of mandatory masking with no exemption for smoking on outdoor smoking. Methods: We conducted 253 unobtrusive observations at 10 outdoor smoking hotspots in 33 months from July 2019 to March 2022 and counted smokers and non-smoking pedestrians in fixed boundaries. We conducted interrupted time-series analyses on the monthly mean volume of smokers (persons per hour) using generalized linear models. The independent variables were as follows: time since the first observation, implementation of the mask regulation, time since the regulation, seasonality, and waves 1-5 outbreaks. We checked the robustness of the association using the daily mean volume of smokers as the dependent variable. Two sensitivity analyses were conducted to include the hotspot location or the number of all pedestrians as an offset. Results: Monthly outdoor smoking decreased immediately after the regulation (incidence rate ratio [IRR]: 0.505, 95% confidence interval [CI]: 0.374 to 0.680, P < 0.001). Daily smoking analysis and the two sensitivity analyses supported the results. However, monthly outdoor smoking increased by 11% since the regulation (IRR: 1.110, 95% CI: 1.074 to 1.147, P < 0.001). An exception was observed at the most severe wave 5 outbreak when monthly outdoor smoking decreased (IRR: 0.415, 95% CI: 0.327 to 0.525, P < 0.001). Conclusion: Outdoor smoking fell immediately after mandatory masking, rebounded to pre-pandemic levels, and decreased again at the most severe wave 5.

Cigarettes, heated tobacco products and dual use: exhaled carbon monoxide, saliva cotinine and total tobacco consumed by Hong Kong tobacco users.

BACKGROUND: Independent studies on exhaled carbon monoxide (CO) and saliva cotinine levels in regular heated tobacco product (HTP) users, and how they compare with conventional cigarette (CC) smokers, are lacking. METHODS: A total of 3294 current users of CCs, HTPs or electronic cigarettes (ECs) from a household survey and a smoking hotspot survey were classified into seven groups: exclusive users of CCs, HTPs, ECs; dual users of CCs and HTPs, CCs and ECs, HTPs and ECs; and triple users. We measured exhaled CO level using the piCo Smokerlyzer (n=780) and saliva cotinine using NicAlert cotinine test strips (n=620). Among the seven groups, the differences in (1) CO and cotinine levels were examined using Kruskal-Wallis test, and (2) the average daily tobacco consumption in the past 30 days was examined using multivariable linear regression. RESULTS: Both exclusive and dual users of CCs had a higher CO level than exclusive HTP or EC users (p<0.05). Exhaled CO levels were similar between HTP and EC users, as were saliva cotinine levels among the seven groups. Compared with exclusive CC users, those who also used HTPs or ECs smoked fewer CCs (CCs+HTPs: adjusted coefficient -2.79, 95% CI -3.90 to -1.69; CCs+ECs: -1.34, 95% CI -2.34 to -0.34), but consumed more tobacco sticks equivalent in total (2.79 (95% CI 1.61 to 3.96); 1.95 (95% CI 0.79 to 3.12)). CONCLUSIONS: HTP or EC use showed lower exhaled CO but similar saliva cotinine levels compared with CC use. Dual users of CCs and HTPs/ECs smoked fewer CCs than exclusive CC users, but consumed more tobacco in total.

Changes in Tobacco Use in the Early Phase of Coronavirus Disease 2019 Pandemic in Hong Kong: A Qualitative Study.

INTRODUCTION: Changes in tobacco use and related personal and environmental factors amid the coronavirus disease 2019 (COVID-19) pandemic can be captured by qualitative studies, but they are few in non-Western populations. AIMS AND METHODS: We assessed the perceived links between tobacco use and COVID-19, and changes in the use of cigarettes, electronic cigarettes (ECs), and heated tobacco products (HTPs) in the early phase of the pandemic in Hong Kong, where lockdown was not implemented. Semi-structured telephone interviews were conducted from January to June 2021 in 95 participants (36 EC users, 28 HTP users, and 32 exclusive cigarette users). Transcriptions were coded using deductive and inductive approaches, and factors for changes were nested in the social-ecological model. RESULTS: Two-thirds of participants perceived their infection susceptibility was the same as never tobacco users, and 44.2% perceived more severe COVID-19 disease if infected. Amid the pandemic, tobacco use decreased overall but increased indoors for all three products. Increased tobacco use was mostly attributed to increased emotional distress, while decreases were attributed to various personal (health concerns) and environmental factors (e.g., COVID-19 regulations). Perceived convenience and lower costs were reasons for increased EC use. Limited access to HTPs was compensated by cigarette use. CONCLUSIONS: Many participants were unaware of the potential harm of tobacco use on COVID-19. Overall tobacco use decreased due to COVID-19 regulations, which may not be sustainable post-pandemic. Indoor consumption increased, supporting a comprehensive smoke-free policy that covers private indoor areas. Better cessation services targeting EC, HTP, and cigarette use are needed. IMPLICATIONS: Smokers need better awareness of the risk of tobacco use on COVID-19. Smoking cessation services can be improved by offering brief advice, strengthening advocacy against secondhand smoke, and covering EC and HTP use, highlighting their potential harms to users and others, and their risk of addiction and relapse to cigarette use.

Changes in tobacco use at the early stage of the COVID-19 pandemic: Results of four cross-sectional surveys in Hong Kong.

INTRODUCTION: Changes in tobacco use since the COVID-19 outbreak differed by countries and little is known about changes in the use of specific tobacco products. METHODS: We analyzed data from four cross-sectional telephone/online surveys from April to June 2020 to investigate such changes since the 1st and 2nd wave outbreaks (February to April 2020) in Hong Kong. The respondents were 1595 adults (83.2% male) who used tobacco before the COVID-19 outbreak from our previous intervention study and surveys. We investigated the changes in tobacco use, intention to quit and quit attempts during the outbreak. RESULTS: About two-thirds (65.3%) of respondents reported no change in overall tobacco use, while 23.1% used less (including cessation) and 11.6% used more, resulting in a net decrease of 11.5 percentage points. A greater net decrease was observed for cigarettes (14.3% points) than heated tobacco products (HTPs, 3.3% points) and electronic cigarettes (e-cigarettes, 2.5% points). Decreased use was mainly due to the more extended stay at home (63.2%), health considerations (52.6%) and mask-wearing (47.4%), while increased use was for passing time (75.0%) and releasing stress (46.4%). Eight percent of cigarette, HTP and e-cigarette users reported a higher intention to quit since the pandemic outbreak. Nineteen percent of tobacco users (176/948) attempted to quit during the pandemic. Only 2.9% (46/1569) were abstinent at the time of the survey. CONCLUSIONS: Overall tobacco use decreased after the first two waves of the COVID-19 outbreak in Hong Kong. A greater proportion of cigarette users decreased use than HTP and e-cigarette users. Given the different methods used in the four surveys, future studies should aim for a large and representative sample.

Use patterns of cigarettes and alternative tobacco products and socioeconomic correlates in Hong Kong secondary school students.

Smoking is a major cause of health inequities. However, sociodemographic differences in adolescent tobacco use are unclear. In a territory-wide school-based anonymous survey in 2018/19, we investigated tobacco use and sociodemographic correlates in 33,991 students (mean age 14.8 ± 1.9 years) in Hong Kong. Tobacco use prevalence and current-ever use ratios by sociodemographic factors were calculated. Generalised linear mixed models were used in association analyses. Current use was highest for cigarettes (3.2%), closely followed by alternative tobacco products (3.0%). Current-ever use ratios were highest for heated tobacco products (HTPs, 0.60), followed by nicotine e-cigarettes (0.52), waterpipe (0.51), and cigarettes (0.35). Use prevalence and current-ever use ratios of all products showed curvilinear relations with perceived family affluence (P values < 0.01), being highest in the richest families. Tobacco use was also associated with more senior grades, the lowest parental education, and boys, but current-ever use ratios of HTPs and waterpipe were higher in girls (P values < 0.05). The results suggested that adolescent ever users of nicotine-containing alternative tobacco products were more likely to keep using them than cigarettes, and the richest adolescents were at the highest risks of tobacco use. Diverse tobacco control measures are needed to improve health equity, especially on alternative tobacco products.

Characterization of Respiratory Symptoms Among Youth Using Heated Tobacco Products in Hong Kong.

Importance: Heated tobacco products (HTPs) are promoted as less harmful than combustible cigarettes but epidemiological evidence is scarce, especially in youth. Objective: To investigate the associations of persistent respiratory symptoms with HTP use, cigarette use, and dual use among Hong Kong youth. Design, Setting, and Participants: This was a territorywide cross-sectional school-based survey conducted from October 2018 to July 2019 using an anonymous questionnaire. Schools were randomly invited from a proportionate stratified sample in all 18 districts of Hong Kong. Poisson regression models using generalized estimating equations yielded adjusted prevalence ratios (APRs) of respiratory symptoms in (1) former and current HTP (vs never) users in the whole sample and stratified by cigarette use status and (2) exclusive HTP and dual users vs exclusive cigarette users. Statistical analysis was performed from October 2020 to March 2021. Exposures: Former and current use of cigarettes, HTPs, e-cigarettes, and other tobacco products. Main Outcomes and Measures: Respiratory symptoms for 3 consecutive months in the past 12 months. Results: The study included 33 627 students with a mean (SD) age of 14.8 (1.9) years; 51.3% (18 171) were boys. Respiratory symptoms were reported by 16.3% (n = 5549) of all students, 29.3% (n = 226) of current users of e-cigarettes, 31.2% (n = 314) of current users of cigarettes, and 33.5% (n = 179) of current users of HTPs. Respiratory symptoms were associated with former (APR, 1.30; 95% CI, 1.06-1.59) and current (APR, 1.59; 95% CI, 1.23-2.06) vs never HTP use and current vs never cigarette use (APR, 1.50; 95% CI, 1.30-1.74) after adjusting for various tobacco use. Associations between respiratory symptoms and current vs never HTP use were observed in never (APR, 1.88; 95% CI, 1.36-2.59) and former (APR, 2.15; 95% CI, 1.12-4.12) cigarette users, but not in current cigarette users (APR, 1.24; 95% CI, 0.97-1.59). Respiratory symptoms were associated with exclusive ever HTP use (APR, 1.46, 95% CI, 1.15-1.86) and ever dual use (APR, 1.29; 95% CI, 1.08-1.54) vs exclusive ever cigarette use. There was no association between exclusive current HTP (vs cigarette) use and respiratory symptoms (1.40; 95% CI, 0.93-2.11). Conclusions and Relevance: This cross-sectional study found that former and current HTP use were associated with persistent respiratory symptoms among youth, especially among never and former cigarette users. Respiratory symptoms were more prevalent in ever exclusive HTP users and ever dual users than ever exclusive cigarette users. These findings suggest that using HTPs instead of cigarettes may not reduce health risks.

Exposure to e-cigarette advertising, attitudes, and use susceptibility in adolescents who had never used e-cigarettes or cigarettes.

BACKGROUND: Tobacco advertisements have been banned in Hong Kong, but low intensity e-cigarette (EC) advertising can still be found in various media outlets. We investigated the associations between exposure to EC advertising and susceptibility to EC use in adolescents who had never used cigarettes or ECs, with potential mediation by attitudes towards ECs and the tobacco industry. METHODS: The School-based Smoking Survey 2016/17 assessed exposure to EC advertising in the past 30 days, attitudes towards ECs and the tobacco industry, susceptibility to EC use, and other covariates. Generalised linear mixed models and multiple mediation analysis methods were used in data analyses. RESULTS: Among 7082 students (mean age 14.9 years), 28.8% reported exposure to EC advertising. Exposure was associated with being uncertain about the harm of EC use, being tolerant towards ECs, believing the tobacco industry is respectable, and being susceptible to EC use; the magnitudes of these associations increased with the number of types of advertising exposed (0, 1, and ≥ 2) (all p-values < 0.01). These attitudinal factors were in turn associated with EC use susceptibility (all p-values < 0.001). The perception that tobacco companies make youth smoke was not associated with the advertising exposure or EC use susceptibility. Of the total effects of EC advertising on use susceptibility, only 16.6% were mediated by attitudinal factors: perceived harm (3.1%), attitudes towards ECs (8.2%), and attitudes towards the tobacco industry (4.9%). CONCLUSIONS: Even exposure to low intensity EC advertising was associated with susceptibility to EC use in adolescents who had never used cigarettes or ECs. The association was weakly mediated by tolerant attitudes towards ECs and the tobacco industry. The government should reinforce the regulations on EC advertising to protect adolescent health.

Adolescent Smoking in Hong Kong: Prevalence, Psychosocial Correlates, and Prevention.

Preventing adolescent smoking is important as smoking is typically initiated by young people. This article reviews the prevalence, psychosocial correlates, and prevention of smoking in Hong Kong adolescents. The past 30-day smoking prevalence in adolescents decreased from 9.6% in 2003 to 2.5% in 2017. Tobacco advertisements, parental and best friends smoking, nonintact families, poor family relationships, lower socioeconomic status, being a new immigrant, poor knowledge of smoking-related harm, positive attitudes toward smoking, overestimation of peer smoking, and depressive symptoms were positively associated with smoking outcomes, whereas positive youth development, authoritative mother and permissive father, family functioning, school competence, and stronger tobacco industry denormalization beliefs were protective against smoking. Along with tobacco tax increase, ban on tobacco advertisements, smoke-free law and pictorial warnings, educational efforts through theater performances, social norms campaigns, and positive adolescent training programs have been conducted to prevent adolescent smoking. To achieve the ultimate goal of tobacco endgame, further tax increase, plain packaging, banning point-of-sale display of tobacco products, smoke-free area extension, and raising minimum age of purchase should be implemented. The government proposed law to ban e-cigarettes, and heated tobacco products should be passed soon to protect children and adolescents from using these products.

School-level electronic cigarette use prevalence and student-level tobacco use intention and behaviours.

Prevalent electronic cigarette (e-cigarette) use in schools may undermine tobacco denormalisation, and thus increase tobacco use in students. We investigated the associations of school-level e-cigarette use prevalence with student-level intention and behaviours related to e-cigarettes, cigarettes, and other tobacco products. In a 2014-15 school-based cross-sectional survey of 41035 secondary school students (grade 7-12; age 11-18 years) in Hong Kong, information was collected on the use of e-cigarettes, cigarettes, and non-cigarette tobacco products (NCTPs), susceptibility to e-cigarette and cigarette use, intention to quit cigarette smoking, and sociodemographic characteristics. The adjusted odds ratio (AOR) of e-cigarette use susceptibility in relation to high (vs low) school-level e-cigarette use prevalence was 1.40 (95% CI 1.05-1.87) in never e-cigarette users. The AORs of cigarette smoking susceptibility in relation to medium and high (vs low) school-level e-cigarette use prevalence were 1.24 (1.01-1.52) and 1.34 (1.02-1.75), respectively, in never cigarette smokers. School-level e-cigarette use prevalence was associated with ever and past 30-day cigarette smoking, but not with intention to quit (in past 30-day cigarette smokers) or past 30-day NCTP use. The findings highlight the importance of strictly banning e-cigarettes in schools, and add to the evidence that prevalent e-cigarette use in adolescents may increase cigarette smoking prevalence.

Adolescent Support for Tobacco Control Policies and Associations with Tobacco Denormalization Beliefs and Harm Perceptions.

Public support is crucial for advancing tobacco control policies. We investigated adolescent support for such policies, and its association with potential factors of social denormalization (SD) beliefs of smoking, tobacco industry denormalization (TID) beliefs (negative perceptions of the industry), and harm perceptions of smoking. In a cross-sectional survey in Hong Kong, 13,964 secondary school students (mean age 15.0 years, 51.3% boys) reported their support (yes/no) for each of 14 tobacco control policies (e.g., further increase tobacco tax). Tobacco-related beliefs and perceptions, and smoking status were also measured. Support for the 14 tobacco control policies ranged from 17.6% to 54.1%. In current non-smokers, SD beliefs, TID beliefs, and harm perceptions were all associated with support for all tobacco control policies. In current smokers, the study factors were each associated with support for two to three policies. To conclude, support for tobacco control policies was weak to moderate in Hong Kong adolescents. SD beliefs, TID beliefs, and harm perceptions of smoking were associated with policy support in current non-smokers. In current smokers, the corresponding associations were less consistent or weaker.

Tobacco Industry Denormalization Beliefs in Hong Kong Adolescents.

BACKGROUND: Tobacco industry denormalization (TID) seeks to expose the industry's misconducts. Research on TID beliefs, meaning negative attitudes toward the tobacco industry (TI), may inform TID programs, but was limited to western populations. We investigated TID beliefs and their association with smoking and sociodemographic characteristics in Hong Kong adolescents. METHODS: In a school-based cross-sectional survey of 14214 students (mean age 15.0 years, 51.5% boys), TID beliefs were assessed by two questions: (1) whether the TI was respectable and (2) whether the TI tried to get youth to smoke, each with four options from "definitely no" to "definitely yes." Smoking susceptibility and behaviors were also assessed. Sociodemographic characteristics included age, sex, perceived family affluence, highest parental education, numbers of co-residing smokers, and school-level smoking prevalence. RESULTS: Of all students, 77.6% considered the TI not respectable and 56.6% believed that the TI tried to get youth to smoke. Stronger TID beliefs were inversely associated with smoking susceptibility and behaviors. For example, students considering the TI definitely not respectable (vs. definitely yes) were 56% (95% confidence intervals [CI] = 45% to 66%), 49% (95% CI = 41% to 56%), and 53% (95% CI = 36% to 65%) less likely to be susceptible to smoking (among never-smokers) and be ever- and current smokers, respectively. Of all correlates examined, only younger age and having no co-residing smoker were associated with TID beliefs. CONCLUSIONS: Substantial proportions of Hong Kong adolescents did not hold TID beliefs, but those who did were less likely to smoke. Our results suggest that TID programs may help reduce adolescent smoking. IMPLICATIONS: The TI's misconducts and responsibility for the tobacco epidemic were not well known by Hong Kong adolescents. TID beliefs in this population were inversely associated with smoking. These findings suggest that TID programs in local adolescents may be of value. The investigation into the correlates of TID beliefs found that socioeconomic status and school-level smoking prevalence were not associated with TID beliefs. This suggests that local TID programs targeting adolescents in general, for example, mass-media campaigns, may be more appropriate than those targeting particular schools or selected groups of adolescents.

Perceived family relationship quality and use of poly-tobacco products during early and late adolescence.

BACKGROUND: The role of family relationship in adolescent use of emerging tobacco products, which have become increasingly popular, is unknown. We examined the associations of perceived family relationship quality with current use of poly-tobacco products including cigarettes, electronic cigarettes (e-cigarettes), waterpipe and smokeless tobacco in adolescents. METHODS: Data from a representative sample of 42,250 US grade 7-12 equivalent students (mean ±â€¯SD age 14.6 ±â€¯1.9 years; 51.3% boys) from 75 randomly selected secondary schools in Hong Kong (2012-13) were analysed. Logistic regressions yielded adjusted odds ratios (AORs) for current (past 30-day) use of cigarettes, e-cigarettes, waterpipe, smokeless tobacco and poly-tobacco (≥2 products) in relation to perceived family relationship quality, adjusted for age, sex, perceived family affluence, parental education, family structure, parental and sibling smoking and secondhand smoke exposure at home. Subgroup analyses were conducted to compare the associations in early (aged ≤14 years) versus late (>14) adolescents. RESULTS: The odds of current use increased with worse perceived family relationship quality with AORs (95% confidence interval) of up to 2.92 (2.32-3.68) for cigarettes, 7.28 (4.71-11.2) for e-cigarettes, 5.04 (3.44-7.40) for waterpipe, 8.09 (4.87-13.4) for smokeless tobacco and 5.25 (3.45-8.01) for poly-tobacco products use (all P for trend <.001). The associations for all tobacco use outcomes were stronger in early than late adolescents (all P for interaction <.001). CONCLUSIONS: Dose-response relationships were found between negatively perceived family relationship quality and current poly- and individual tobacco product use by Hong Kong Chinese secondary students. The associations were stronger for alternative tobacco products and in early adolescents.

Favourable Perceptions of Electronic Cigarettes Relative to Cigarettes and the Associations with Susceptibility to Electronic Cigarette Use in Hong Kong Chinese Adolescents.

We investigated favourable perceptions of electronic cigarettes (ECs) relative to cigarettes and their associations with EC use susceptibility in adolescents. Hong Kong Chinese Secondary 1-6 (U.S. grade 7-12) students (n = 40,202) were surveyed in 2014/2015 on EC use, cigarette smoking, favourable perceptions of ECs relative to cigarettes, EC use susceptibility, family smoking, and socio-demographic characteristics. Cox regression yielded adjusted prevalence ratios (APRs) of EC use susceptibility in never users, excluding those unaware of ECs. In all students, 8.9% were ever EC users, 47.2% reported favourable perceptions of ECs relative to cigarettes, such as less likely to cause accidents (25.2%) and less harmful to users (24.5%), and 28.9% did not know ECs. Among never EC users who were aware of ECs (n = 24,663), EC use susceptibility was associated with each of the favourable perceptions, especially greater attractiveness (APR 2.84, 95% CI 2.53-3.19), and better parental (2.75, 2.41-3.15) and school acceptability (2.56, 2.15-3.05). An increased number of favourable perceptions of ECs relative to cigarettes was associated more strongly with the susceptibility (p for trend < 0.001). Our findings inform strategies to reduce unwarranted favourable perceptions and prevent adolescent EC use.

Exclusive and concurrent use of cigarettes and alternative tobacco products among Hong Kong adolescents.

INTRODUCTION: The use of alternative tobacco products (ATPs) is becoming increasingly popular among the youth. This study aimed to assess cigarette-only smoking, exclusive ATP use, and concurrent use (cigarettes and ATPs) among adolescents in Hong Kong. METHODS: We analyzed data of the Hong Kong School-based Survey on Smoking among Students 2012/13 from a representative sample of 45 857 secondary school students. Weighted prevalence of cigarette-only smoking, exclusive ATP use, and concurrent tobacco use were calculated. Multinomial logistic regression examined correlates of exclusive ATP use and concurrent use relative to cigarette-only smoking. Among current (past-30-days) cigarette smokers, multivariable logistic regression assessed whether ATP use was associated with nicotine dependence, quit intention and quit attempt. RESULTS: Overall, 5.8% of adolescents reported current tobacco use (2.1% cigarette-only smoking, 2.5% exclusive ATP use and 1.2% concurrent use). Compared with cigarette-only smoking, exclusive ATP use and concurrent tobacco use were associated with younger age, higher perceived family financial status, absence of cigarette smoking peers, poor knowledge about smoking and more frequent alcohol use. Among current cigarette smokers, ATP use was negatively associated with cigarette quit intention and quit attempt. CONCLUSIONS: ATP use was as prevalent as cigarette smoking among adolescents, and ATP users were different from cigarette smokers in many demographic and psychosocial factors. Tobacco control programs among youth should target different types of tobacco users and address all forms of tobacco products.

Secondhand Smoke From Multiple Sources, Thirdhand Smoke and Respiratory Symptoms in Hong Kong Adolescents.

Introduction: Reports on involuntary tobacco smoke exposure in children have focused mostly on secondhand smoke (SHS) from smoking inside the home. We studied the separate and combined prevalence of SHS exposure from multiple sources and thirdhand smoke (THS) and the associations with respiratory symptoms in Hong Kong adolescents. Methods: In 2010-2011, 61 810 Secondary 1 (US Grade 7) to seven students reported their smoking status, respiratory symptoms, and exposure to four sources of tobacco smoke in the past 7 days. Weighted prevalence of exposure was calculated. Associations with respiratory symptoms were analyzed in 50 762 never smokers using logistic regression. Results: Tobacco smoke exposure at home was 23.2% considering SHS exposure from inside the home, but increased to 33.2% including SHS from neighbors and 36.2% further including THS. Including SHS outside home (55.3%), 63.3% of adolescents were exposed to SHS anywhere or THS at home. In never smokers, SHS from each source and THS at home were linearly associated with respiratory symptoms. Exposure to more sources yielded stronger associations with respiratory symptoms (p for trend<.001). The adjusted odds ratios (95% CI) were 1.04 (0.97-1.11), 1.12 (1.03-1.22), 1.40 (1.26-1.56) and 1.99 (1.74-2.28) for 1, 2, 3, and 4 sources, respectively. Conclusions: Although Hong Kong's smoking prevalence is among the lowest in the developed world, over 60% of its adolescents were involuntarily exposed to tobacco smoke from one or more sources with a linear association with respiratory symptoms in never smokers. More stringent policies are needed to protect adolescents from tobacco smoke. Implications: In a high-density urban setting, involuntary exposure to tobacco smoke in adolescents can be much higher than the smoking prevalence of the general population, especially if SHS exposure from multiple sources and THS are also considered. Such exposures have important health implications as demonstrated by their linear associations with respiratory symptoms. Tobacco control measures effective in reducing smoking prevalence may have little effect in reducing adolescent exposure to tobacco smoke, especially in the private home, in which other public health strategies are urgently needed.

Associations of perceived interparental relationship, family harmony and family happiness with smoking intention in never-smoking Chinese children and adolescents: a cross-sectional study.

OBJECTIVE: To examine the associations of perceived interparental relationship, family harmony and family happiness with smoking intention in never-smoking Chinese children and adolescents in Hong Kong. DESIGN, SETTINGS AND PARTICIPANTS: Cross-sectional surveys of 15 753 primary (grades 4-6) and 38 398 secondary (grades 7-12) never-smoking students from 71 to 75 randomly selected primary and secondary schools in Hong Kong, 2012-2013. MEASUREMENTS: Outcome variable was smoking intention which denoted any affirmative response to smoke within the coming year or when a cigarette was offered by a good friend. Exposure variables were perceived interparental relationship and family harmony each measured on a five-point scale from 'very good' to 'very bad' and perceived family happiness on a four-point scale from 'very happy' to 'not happy at all'. Potential confounders included age, sex, family structure, perceived family affluence, parental smoking and sibling smoking. RESULTS: In primary students, the adjusted ORs (AORs) (95% CI) of smoking intention generally increased with more negative perception of the family relationship: up to 3.67 (1.91 to 7.05) for interparental relationship, 7.71 (4.38 to 13.6) for family harmony and 5.40 (3.41 to 8.55) for family happiness. For secondary students, the corresponding AORs (95% CI) were 2.15 (1.64 to 2.82) for interparental relationship, 2.98 (2.31 to 3.84) for family harmony and 2.61 (1.80 to 3.79) for family happiness. All p for trend <0.001. CONCLUSIONS: More negatively perceived interparental relationship, family harmony and family happiness were associated with higher odds of smoking intention with dose-response relationships in never-smoking Chinese children and adolescents in Hong Kong. Children's perception of their family relationship may be an important intervening point for preventing youth from initiating smoking.

Associations of unhappiness with sociodemographic factors and unhealthy behaviours in Chinese adolescents.

Background: Evidence on the effects of lack of physical exercise, alcohol drinking and smoking on happiness is limited and inconsistent. We examined the associations of unhappiness with sociodemographic factors and these unhealthy behaviours in Chinese adolescents. In a school-based survey in 2012-13 in Hong Kong, 45 857 secondary school students (mean age 14.8 years, 54.0% boys) reported their happiness level (not happy at all/not very happy/happy/very happy), frequency of physical exercise, alcohol drinking status, smoking status and sociodemographic factors. A main and a sensitivity analysis examined the associations of unhappiness with the study factors, treating unhappiness as a binary (combining 'not happy at all' and 'not very happy') and a four-level ordered variable, respectively. The main and the sensitivity analysis both showed that unhappiness was associated with older age, very poor families, non-intact families, more co-residing smokers, lack of physical exercise and alcohol drinking; current smokers were unhappier than never and ex-smokers; unhappiness also increased significantly with the number of unhealthy behaviours ( P for trend < 0.001). In Chinese adolescents, unhappiness levels were higher in those who had a very poor family, a non-intact family and more co-residing smokers, and in those who were physically inactive, drank alcohol and smoked.

The relationship of waterpipe use with cigarette smoking susceptibility and nicotine dependence: A cross-sectional study among Hong Kong adolescents.

INTRODUCTION: Waterpipe smoking has become increasingly popular in adolescents. We examined the association of waterpipe smoking with cigarette smoking susceptibility and nicotine dependence among adolescents in Hong Kong. METHODS: We analyzed the data of School-based Survey on Smoking among Students 2012/13 from a representative sample of 45,857 secondary school students (US grades 7-12) in Hong Kong. Among never cigarette smokers (n=37,740), we conducted chi-square test to compare cigarette smoking susceptibility by current (past 30-day) waterpipe smoking status, and used multivariate logistic regression to examine the association between current waterpipe smoking and cigarette smoking susceptibility controlling for age, sex, peer cigarette smoking, and living with a cigarette smoker. Then we conducted chi-square test and multivariate logistic regression among current cigarette smokers (n=1694) to examine the relationship of current waterpipe smoking with two nicotine dependence outcomes, including heavier smoking (≥5 cigarettes/day) and first cigarette within 30min of waking, controlling for demographics and the number of smoking days in the past 30days. RESULTS: Among never cigarette smokers, current waterpipe use was associated with cigarette smoking susceptibility (adjusted odds ratio [AOR]=3.58, 95% confidence interval [CI]: 1.61-7.97). Of current cigarette smokers, waterpipe use was associated with heavier smoking (AOR=1.56, 95% CI: 1.00-2.43) and first cigarette within 30min of waking (AOR=2.08, 95% CI: 1.35-3.19). CONCLUSIONS: Surveillance, prevention, and intervention programs should address waterpipe use in addition to cigarette smoking. Educational programs need to inform youth about the harmful and addictive effects of waterpipe smoking. Public health campaigns deglamourizing waterpipe use may help reduce waterpipe smoking among youth.

Electronic cigarette use among adolescents: a cross-sectional study in Hong Kong.

BACKGROUND: Little is known about electronic cigarette (e-cigarette) use among Chinese adolescents. We examined the prevalence of current (past 30-day) e-cigarette use and its associated factors in a large sample of adolescents in Hong Kong. METHODS: We analyzed data of the School-based Survey on Smoking among Students 2012/13 from a representative sample of 45,857 secondary school students (mean age: 14.8 ± 1.9). We conducted chi-square tests and t-test to compare current e-cigarette use by covariates. We used multivariable logistic regression to examine the association between current e-cigarette use and demographic variables, parental smoking, peer smoking, knowledge about the harm of cigarette smoking, attitudes toward cigarette smoking, cigarette smoking status, use of other tobacco products, and alcohol consumption. RESULTS: Overall, 1.1% of students reported current e-cigarette use. Of e-cigarette users, 11.7% were never-cigarette smokers, 15.8% were experimental cigarette smokers, 39.3% were former cigarette smokers, and 33.2% were current cigarette smokers. Current e-cigarette use was associated with male sex, poor knowledge about the harm of smoking, cigarette smoking, use of other tobacco products, and alcohol consumption. CONCLUSIONS: Surveillance and intervention efforts should address a wide range of tobacco products, including e-cigarettes. Tobacco cessation programs should also address alcohol use collectively. Policies prohibiting e-cigarette sales to minors may help prevent e-cigarette uptake among adolescents.

Waterpipe smoking among secondary school students in Hong Kong.

OBJECTIVES: To examine the prevalence of waterpipe smoking and its associated factors among adolescents in Hong Kong. METHODS: We analyzed data of the School-based Survey on Smoking among Students 2012/2013 from a representative sample of 45,857 secondary school students in Hong Kong (mean age 14.8, SD 1.9). We conducted Chi-square tests and t test to compare current (past 30 days) waterpipe users and nonusers by sociodemographic variables and other covariates. Univariate and multivariable logistic regression models were used to examine the factors associated with current waterpipe smoking. RESULTS: Overall, 1.2 % of students reported current waterpipe smoking, of whom 43 % reported concurrent use of cigarettes. Waterpipe was the most popular alternative tobacco product (non-cigarette) used by students. Current waterpipe smoking was associated with older age, male sex, higher self-perceived family financial status, poor knowledge about the harm of cigarette smoking, positive attitudes toward smoking, current cigarette smoking, other tobacco use, and alcohol consumption. CONCLUSIONS: Waterpipe smoking was the most popular alternative tobacco product among Hong Kong adolescents. Despite the low prevalence, it should be routinely monitored. Education programs and cessation interventions need to address waterpipe smoking in addition to cigarette smoking.