Waterpipe use in Germany (2018 - 2024): Prevalence and sociodemographic differences in age of initiation.

Background: Waterpipe (WP) use poses not only a risk of nicotine dependence but also additional health hazards. This study examined trends in WP use in Germany, focusing on prevalence by age group and differences in initiation age.

Methods: We analysed data from 76,239 respondents (≥ 14 years) from the German Study on Tobacco Use (DEBRA); a series of bi-monthly national surveys using face-to-face interviews at home (2018 - 2024). Prevalence trends were modelled using binomial logistic regression models with restricted cubic splines.

Results: The prevalence of WP use decreased over time, to an estimated 0.9 % (95 % CI = 0.6 - 1.2) by mid-2024. This prevalence is made up of 0.1 % (95 % CI = 0.0 - 0.2) 14- to 17-year-olds, 0.3 % (95 % CI = 0.2 - 0.6) 18- to 24-year-olds, 0.3 % (95 % CI = 0.2. - 0.4) 25- to 39-year-olds, and 0.2 % (95 % CI = 0.1 - 0.3) people aged 40 years and older. WP use increased until 2020 up to 2.8 % (95 % CI = 2.3 - 3.4), remained stable for two years and then decreased, especially among people between 25 and 39 years of age. The proportion of 14- to 17-year-old users and users aged at least 40 years remained stable over the years at a low level. Median initiation age was 18 years (25th percentile: 16 years; 75th percentile: 22 years). A lower initiation age was associated with male gender and lower income.

Conclusions: WP use increased from 2018 - 2020, stabilised from 2020 - 2022, and then decreased until 2024. Median initiation age was 18, with males and people with lower income starting at a younger age. Targeted public health interventions, focusing on younger males and those with lower socioeconomic status, are needed to prevent early use.