Flavoured electronic cigarette use and intention to smoke cigarettes in never smoking Hong Kong adolescents

Abstract

SIGNIFICANCE: Electronic cigarettes (ECs) with nicotine have not been approved legally in Hong Kong, but low cost ECs with many flavours are on sale and easily accessible to young people. We studied flavoured EC use and its relation with smoking intention in never smoking adolescents. METHODS: Of 10923 Secondary 1-6 (US Grade 7-12) students surveyed in 2014/15 in Hong Kong, we analysed 9637 never smokers (n=9637; mean age 14.9, SD 1.8; 49.7% boys). Ever EC users indicated the flavours they had ever used (study factors) with 9 options, including “plain flavour”, 7 specified flavours and “other flavours”. Smoking intention (outcome) referred to choosing any responses other than “definitely not” to smoke cigarettes (i) in the next 12 months, (ii) when good friends smoked in front, or (iii) when a good friend offered a cigarette. Descriptive data were weighted by age, sex and grade. Logistic regression yielded adjusted odds ratios (AORs) of smoking intention for each flavour and the number of flavours used, with “other flavours” treated as a single flavour. Socio-demographic characteristics, family smoking and school clustering effect were adjusted for. RESULTS: In never smokers, 3.2% (95% CI 2.9%-3.6%) had ever used ECs. No user had used plain flavour, while mint (78.4%), coffee (36.7%), candy (6.1%), fruits (3.8%), spice (3.4%), alcohol (1.9%), tobacco (1.6%) and other flavours (25.5%) were reported. Significant associations were observed between smoking intention and using any flavours versus never EC use. Candy and tobacco flavours showed the strongest associations with AOR (95% CI) of 25.44 (7.97-81.13) and 21.42 (1.67-274.37) respectively. In EC users, 20.8% used 2 flavours and 14.9% used 3 or more. Using more flavours was more strongly associated with smoking intention, compared with never EC use. The AOR (95% CI) was 2.62 (1.92-3.59) for 1 flavour, 5.16 (2.94-9.08) for 2 and 9.25 (4.46-19.20) for 3 or more. CONCLUSIONS: Flavoured ECs were popular in never smoking EC users in Hong Kong adolescents. The strong association between using more flavours and smoking intention supports a ban on ECs, especially non-nicotine flavoured ECs, for smoking prevention in adolescents.