We first used the current-ever use ratio as an indicator of how likely a tobacco product is used beyond experimentation among adolescents using cross-sectional data, and showed that adolescent ever users of nicotine-containing alternative tobacco products were more likely to keep using them than users of cigarettes and non-nicotine products, and more girls than boys in ever users of waterpipe and HTPs kept using them despite the lower use prevalences in girls. In addition, we showed the socioeconomic gradient in adolescent users of various tobacco products, and found J-shaped relations that adolescents from the richest families had the highest use prevalences and the middle groups had the lowest use prevalences. Moreover, the most commonly used category was cigarettes in the poorest families, but alternative tobacco products in the richest families.
We found J-shaped relations between family affluence and adolescent tobacco use. The poorest families had higher risks of child tobacco use than the middle-SES families, which could be due to parental smoking, peer influence, single parents, stress, and poor school performance.3,6-10,31 However, compared with those from the poorest families, higher proportions of adolescents from the richest families used the 4 tobacco products, especially alternative products, which were more expensive (a pack of cigarettes cost US$7.1–9.0 including US$4.9 of tax; ECs and HTPs cost US$25–130 per reusable device set in Hong Kong). Our previous study also showed that waterpipe use was more common in Hong Kong adolescents from rich families.32 The affordability of the products could modify the associations between family affluence and tobacco use in adolescents, which was also showed in overseas studies. Adolescents from poor families had higher smoking prevalences in countries and regions where cigarettes were more affordable, such as mainland China (as low as US$0.5/pack)10 and developed countries,6-8 but the differences were smaller in lower-income countries.9,11 In Ghana, smokeless tobacco (tawa) that is cheaper and more readily available than cigarettes, was more commonly used by adolescents from poor families, but cigarette use did not vary by family affluence.11 EC using adolescents in Korea usually had more spending money.33 High-SES adolescents usually used JUUL rather than cheaper EC devices in the US.34
Apart from affordability, several reasons could help explain why alternative tobacco products were more commonly used in the most well-off adolescents. First, new and alternative tobacco products have targeted the middle and upper classes, touting the so-called “premium” and “high-end” lifestyle,35 and this global marketing strongly influences consumers in Hong Kong especially through the internet. Second, privileged social groups are usually exposed to more advertising and they try new products earlier. In England, ECs were first used by high-SES groups before spreading to low-SES groups from 2014 to 2017.36 Third, adolescents and parents from the most affluent families would also be more health conscious and ready to pay a premium for alternative tobacco products that are claimed to be less harmful than cigarettes,23,37-39 especially in Hong Kong, where three-quarters of people were considered to be health conscious.40
We found lower current-ever use ratios for cigarettes (35%) and non-nicotine ECs (22%), and higher current-ever use ratios for nicotine-containing alternative products—HTPs (60%), nicotine ECs (52%) and waterpipe (51%). Based on the results of the National Youth Tobacco Survey (NYTS) 2019 in US students (grade 7–12),41 the current-ever use ratio calculated by us was 57.1% for ECs and 26.1% for cigarettes. The current-ever use ratio of nicotine ECs in Hong Kong appeared to be similar to that of ECs in the US where almost all ECs (99%) contain nicotine.42 High nicotine concentrations in products including JUUL and IQOS expose youth to high risk of addiction,43 and an adult study also shows that HTPs could reinforce nicotine dependence, rather than serving as a cessation aid.44 In addition, alternative tobacco products with kid-friendly flavours are less irritant than cigarettes,45 which may encourage regular use. We found higher current-ever use ratios of nicotine-containing alternative tobacco products in girls than boys, despite their lower prevalences of use. Prior studies also showed that women and teenage girls were more prone to nicotine addiction after smoking initiation,46 and had more difficulties in quitting.47 Researchers and tobacco control advocates should pay close attention to use progressions and nicotine dependence in adolescent users of alternative tobacco products, especially in girls. On the other hand, persistent use in experimenters of non-nicotine EC products should also be monitored.
Given the J-shaped relations between family affluence and various tobacco use, we propose to adopt diverse tobacco control measures to improve health equity. Raising tobacco taxes and prices is regarded as the most effective in curbing tobacco use in adolescents and disadvantaged groups.48 However, it may be less effective in reducing alternative tobacco product use, especially in high-income families. Total bans on advertising and sponsorship of new and alternative tobacco products should be strictly enforced. Hong Kong SAR Government has proposed a total ban of ECs and HTPs in February 2019, but it encounters strong resistance from the tobacco industry and some pro-industry legislators. The bills are still under debate as of 5 February 2021. As our results have shown that adolescent experimenters of alternative tobacco products were more prone to persistent use than cigarette experimenters, this total ban would greatly prevent the epidemic of adolescent tobacco use.
This study had some limitations. First, because our study was cross-sectional, the temporal sequence was uncertain. However, the risk factors (family SES) were unlikely to have been influenced by the outcomes (adolescent tobacco use). Second, the higher current-ever use ratios of new tobacco products might be partly due to their shorter history so that recent use would be more likely. The latest product included in this study was HTP, which became available and popular in Hong Kong only 1–2 years before this survey. Further studies are needed to confirm the findings.
Alternative tobacco product use has become as common as cigarette use. We have first shown by using the current-ever use ratio that, higher proportions (over half) of the ever users of nicotine-containing alternative tobacco products kept using them than users of cigarettes and non-nicotine products. Ever and current use prevalences and current-ever use ratios of cigarettes, e-cigarettes, HTPs and waterpipe showed J-shaped relations with family affluence, being highest in the richest families and lowest in the middle groups. High use prevalences of all products were associated with higher grades, the lowest parental education and boys, but current-ever use ratios of HTP and waterpipe were higher in girls. Such alarming situation needs urgent and strong regulations on tobacco products, especially in regions where new products are emerging.