Risk of cutaneous malignant melanoma in patients with celiac disease: a population-based study.

BACKGROUND Celiac disease (CD) carries an increased risk of several malignancies, including cancers of the gastrointestinal tract and hematologic malignancies. The disease course of cutaneous malignant melanoma (CMM) is affected by the immune status of the host, and therefore may be associated with CD. OBJECTIVE We sought to test for an association between CD and CMM in a population-based setting. METHODS We queried all (n = 28) pathology departments in Sweden and identified patients with intestinal histology consistent with CD. Each patient was matched to up to 5 control subjects by age, gender, calendar period, and region. Using Cox proportional hazards, we tested for an association between CD and the subsequent diagnosis of CMM. RESULTS Among patients with CD (n = 29,028), 78 subsequently developed CMM (0.3%). Compared with control subjects there was no significant association between CD and CMM (hazard ratio 0.94, 95% confidence interval 0.73-1.20). This null association was similar for men (hazard ratio 0.99, 95% confidence interval 0.68-1.44) and women (hazard ratio 0.89, 95% confidence interval 0.64-1.24), and in all age strata. LIMITATIONS Lack of data regarding undiagnosed CD is a limitation. CONCLUSION In this population-based study we found no association between CD and the subsequent diagnosis of CMM. Prior studies showing a positive association between these 2 entities may have been a result of referral bias.