Background
Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections remain major global public health challenges and are leading causes of liver cirrhosis and hepatocellular carcinoma. While well-established transmission routes include injection drug use, sexual, and vertical transmission, infection routes are sometimes unidentified, hindering progress toward the WHO hepatitis elimination goals. Tattooing is a recognized but insufficiently quantified route of HBV/HCV transmission and has become increasingly common worldwide. Existing evidence is largely descriptive or based on analytical studies with limited control for confounding.
Objectives
To assess the risk of HBV and HCV infection associated with tattooing overall, and by tattoo characteristics, including tattooing context (inside vs outside studios) and the regulatory environment of the country where the tattoo was obtained.
Methods
We used data from the Cancer Risk Associated to the Body Art of Tattooing (CRABAT) study, a sub-study of the French population-based Constances cohort including 77,826 individuals aged ≥45 years who completed questionnaires on tattoo exposure. HBV and HCV infections were identified through self-reports and national health insurance records. Associations between tattooing (yes/no), tattooing context, and regional regulatory frameworks (countries with vs without national tattoo hygiene regulations in place for ≥10 years) were examined using multivariate logistic regression and Cox proportional hazards models. Analyses were adjusted for major HBV/HCV risk factors (e.g., number of sexual partners, homosexual intercourse among men). Individuals with HIV infection or proxy indicators of injection drug use were excluded.
Results
Overall, 7.4% of participants reported having at least one tattoo. Tattooed individuals had a higher prevalence of any hepatitis infection compared with non-tattooed individuals (adjusted prevalence odds ratio [POR] 1.49; 95% CI: 1.16–1.91), largely driven by HCV infection. The strongest association was observed for tattoos performed outside studios, which was associated with a markedly increased risk of HCV infection (hazard ratio [HR] 4.14; 95% CI: 2.33–7.35). Tattoos obtained in countries without long-standing hygiene regulations were associated with increased HBV risk (HR 3.22; 95% CI: 1.39–7.44). No increased risk of HBV or HCV was observed for tattoos performed exclusively in studios. Extrapolation to the population level suggests that more than 11,000 prevalent HCV infections in France among adults aged 45–75 years may be attributable to tattoos performed outside studios.
Conclusions / Implications
Unsafe tattooing practices represent a preventable and likely underestimated risk factor for HBV and HCV transmission in the general population. Infection risk was highly context-dependent, with no excess risk observed for tattoos performed in studios or in countries with strict hygiene regulations. As tattooing continues to expand globally, including in regions with high HBV/HCV prevalence and limited regulatory oversight, urgent public health action is needed. Beyond strengthening and harmonizing tattoo hygiene regulations, targeted awareness campaigns are required to discourage unsafe tattooing practices. Future research should estimate the global burden of tattoo-associated HBV/HCV infections and related cancers and assess the feasibility and effectiveness of implementing HBV/HCV point-of-care testing in tattoo studios.