Psoriasis in a nationwide cohort study of patients with celiac disease

Earlier studies on the association between celiac disease (CD) and psoriasis show contradictory results. The purpose of this study was to assess the risk of psoriasis in patients with biopsy-verified CD. Through 28 pathology departments in Sweden, we identified individuals with CD diagnosed between 1969 and 2008 (Marsh 3: villous atrophy; n = 28,958 unique individuals). We then used Cox regression to compare individuals with CD with 143,910 sex- and age-matched controls regarding their risk of psoriasis. CD was a risk factor for future psoriasis (hazard ratio (HR) = 1.72; 95% confidence interval (CI) = 1.54-1.92; during follow-up, 401 individuals with CD and 1,139 controls had a diagnosis of psoriasis). The absolute risk of future psoriasis in patients with CD was 135/100,000 person-years (excess risk = 57/100,000). In all, 42% of all psoriasis in patients with CD could be attributed to the underlying CD. Moreover, in children we saw a positive association between CD and psoriasis (HR = 2.05; 95% CI = 1.62-2.60). The association between CD and psoriasis seems to be independent of a temporal relationship, as we also found a positive association between CD and psoriasis before CD diagnosis (odds ratio = 1.91; 95% CI = 1.58-2.31). In conclusion, individuals with CD were at increased risk of psoriasis both before and after CD diagnosis.