Tattoo practices and risk of hepatitis B and hepatitis C infection in the general population

ObjectivesTo prevent hepatitis B (HBV) and hepatitis C (HCV) infections and associated deaths from hepatocellular carcinoma and cirrhosis, better identification of transmission routes is needed. Here, we reassessed the impact of different tattooing practices on viral transmission. DesignPopulation based cohort-study. SettingCancer Risk Associated to the Body Art of Tattooing (CRABAT) cohort as part of the ongoing French national cohort study Constances (baseline examination from 2012-2018). Participants110,402 participants (60,387 women and 50,015 men), of which 11.6% (12,789) were tattooed as per Constances follow-up questionnaire 2020. Complete exposure data on different exposure settings and countries of tattooing collected via complementary exposure assessment in 2023 (response rate 60%) was available for 7740 tattooed (4930 women and 2810 men) participants. Main outcome measuresSelf-reported HBV and HCV infections that were confirmed by surface antigen testing (HBsAG) and antibody (Anti-HCV) testing, respectively. Associations of different tattoo exposure characteristics (any tattoo; tattooed in/outside tattoo parlours; tattooed in/outside regulating countries; no tattoos (reference)) on subsequent HBV and/or HCV infections were assessed via multivariate logistic regression models, minimally adjusted and adjusted for known hepatitis risk factors, in the population >=45 years. Post-hoc, number of preventable HCV infections due to unsafe tattooing outside tattoo parlours was estimated. ResultsIn fully adjusted models, tattooing was associated with increased risk of any hepatitis infection (Odds ratio (OR): 1.46 (95% confidence interval: 1.15; 1.86), with a particularly strong increased risk for HCV (2.26 (1.64; 3.11)) compared to HBV (1.08 (0.77; 1.52)) infection. The increased risk for HCV and to a lesser extend for HBV was due to tattooing outside tattoo parlours (HCV: 4.75 (2.81; 8.03); HBV: 1.88 (0.99; 3.57)) whereas tattooing outside regulating countries was associated with an increased risk for HCV (2.74 (1.00; 7.45) and HBV (1.96 (0.80; 4.84)). Risk of HBV and/or HCV were around 10-fold for tattooing outside tattoo parlours outside regulating countries. The estimated number of preventable HCV infections through safe tattoo practices was around 12,000 in France and over 150,000 in Europe. ConclusionThe impact of unsafe tattooing practices as a preventable risk factor for HCV transmissions is highly underestimated. What is already known on the topic?O_LITattooing was identified as a potential transmission route for hepatitis infections in the early 1990s. C_LIO_LIHygiene measures were implemented in tattoo parlours throughout (many) European countries to prevent bloodborne infection transmission through tattooing needles. C_LIO_LICurrent hepatitis prevention strategies rarely/never consider tattooing as a common transmission route. C_LI What this study addsO_LIUnsafe tattooing practices are very common. One in four tattooed people got at least one tattoo outside parlours and one in five got tattooed in a country without strict hygiene regulations. C_LIO_LIUnsafe tattooing practices strongly increase the risk of HCV and to a lesser extend for HBV, making it the most important HCV transmission route after injecting drugs. C_LIO_LIThe study provides evidence that raising awareness on unsafe tattooing and upscaling screening of persons that underwent unsafe tattooing might help to substantially reduce hepatitis infections and related morbidity and mortality. C_LI