Psoriasis and Dementia: A Cross-sectional Study of 121,801 Patients.

Data regarding the association between psoriasis and dementia are inconclusive. The aim of this study was to evaluate this association in the database of Clalit Health Services, Israel. A comparative analysis for the association between psoriasis, dementia and its risk factors was performed for the entire study population and in the subgroup of patients with moderate-to-severe psoriasis. The study included 121,801 patients with psoriasis, of whom 16,947 were diagnosed with moderate-to-severe psoriasis, and 121,802 controls. Psoriasis was associated with a lower prevalence of dementia relative to control subjects (1.6% vs 1.8%; odds ratio (OR) 0.85; 95% confidence interval (95% CI) 0.80-0.91; p < 0.001). Multivariate analysis adjusting for demographic variables, cardiovascular-related risk factors, and healthcare utilization demonstrated a significant inverse association between psoriasis and dementia in the entire study population (adjusted OR 0.86; 95% CI 0.76-0.96; p = 0.009), but not in the subgroup of patients with moderate-to-severe psoriasis (adjusted OR 0.91; 95% CI 0.81-1.02; p = 0.113). In conclusion, these data support the hypothesis that psoriasis is inversely associated with dementia.