Prevalence and associated factors of waterpipe tobacco smoking in Japan

INTRODUCTION Despite the global increase in waterpipe tobacco use (hookah tobacco, shisha), its prevalence and characteristics are understudied in Japan. We aimed to investigate the prevalence and associated factors of waterpipe tobacco use in the Japanese population. METHODS Data were obtained from the Japan 'Society and New Tobacco' Internet Survey, conducted in February 2023. Of the 34000 surveyed participants, a total of 31037 respondents (91.3%) aged 15-82 years were included. Current waterpipe tobacco smokers were defined as those reporting use 'occasionally' or 'almost every day' in the past 30 days. Inverse probability weighting was used to calculate waterpipe tobacco use, which approximated the Japanese national population. Logistic regression analyses were conducted to estimate the effect of waterpipe tobacco use, adjusted for sociodemographic variables. RESULTS The prevalence of current and former waterpipe tobacco use in Japan was 1.4% and 3.9%, respectively, both with higher prevalence among men. Use was notably higher among individuals in their 20s, with prevalence rates of 4.4% among those aged 20-29 years. Waterpipe tobacco use among current tobacco product users was 2.5% for cigarette users, 4.7% for heated tobacco product users, and 32.5% for electronic cigarette users. Waterpipe tobacco use was more strongly associated with current e-cigarette (AOR=4.06; 95 % CI: 2.7-6.0) and heated tobacco product (HTP) use (AOR=2.44; 95 % CI: 1.9-3.2), while individuals with former combustible tobacco (AOR=3.12; 95 % CI: 2.4-4.1) or cannabis use (AOR=14.8; 95 % CI: 9.5-23.2) reported higher prevalence of current waterpipe use. CONCLUSIONS We found a high prevalence of waterpipe tobacco smoking among young adults and other tobacco product users in Japan. Public health initiatives should focus on educating the population about the risks associated with waterpipe tobacco use and developing policies to regulate its availability and marketing.