JMIR Publications

ABSTRACT

Background:

The prevalence of decorative tattoos is increasing worldwide. Tattooing is an invasive body art that involves the injection of chemical mixtures into the upper layer of the dermis. Although these mixtures may contain environmental toxins, including known human carcinogens, their long-term health effects are poorly studied. Although epidemiological studies are urgently needed, there is no validated method for assessing tattoo exposure so far.

Objective:

To develop and validate a method to assess ink exposure in the tattooed population suitable for application in large cohort studies.

Methods:

Three preliminary versions of the EpiTAT (Epidemiological Assessment Tool for Tattooing) using the tattoo measurement unit "hand surface", "credit card" or "body schemes", were randomly filled in by tattooed volunteers in Lyon, France. A validation study was conducted with 97 selected respondents to compare the self-assessment with validation measurements of tattoo surface, color and fill made by trained study personnel. Interclass correlation, Kendall's rank correlation and two-tailed Student's t-tests were used to statistically compare tattoo size, color area and tattoo fill. Participants' comments on the questionnaire were also considered. For quality control of validation measures, digital surface analysis of 62 photographs of selected tattoos was performed via Fiji/ImageJ.

Results:

In general, results revealed overestimation of self-assessed compared to validation measures (e.g. mean tattooed body surface 1768 cm2 (SD: 1547) vs. 930 cm2 (SD: 1047; p<0.005) for the “hand surface”), and validation measures to digital image analysis (mean tattoo surface 147 cm2 (SD:303.9) vs 101 cm2 (SD:154.7; p=0.045)). Although the "credit card" approach yielded the most accurate measures for all variables of interest, it had a much lower completion rate (60%; 78/129) compared to "hand surface" (86%; 89/104) and "body patterns" (85%; 90/106). The "hand surface" measured total tattoo size more accurately than the "body schemes" (absolute agreement intraclass correlation coefficients: 0.71 versus 0.64).

Conclusions:

The final version of EpiTAT contains 21 items and uses the "hand surface" as a visual unit of measurement. Likert scales are used to assess color and filling as a proportion of the total tattoo area. Overestimation of tattoo size by self-reporting must be corrected when calculating exposure.