A Utah case-control study of 1,167 melanoma cases and 5,835 controls found that patients with four or more tattoo sessions or three or more large tattoos had lower odds of melanoma, while one tattoo session was linked with higher odds, particularly among women. Patients tattooed before age 20 also showed reduced odds of invasive melanoma. Researchers noted unmeasured confounding due to missing data on indoor tanning, sunburn history, and family history of melanoma. They emphasized the need for further studies to clarify biological mechanisms.

Source: Journal of the National Cancer Institute