Psoriasis is not associated with cognition, brain imaging markers, and risk for dementia: The Rotterdam Study

Background: Based on increased cardiometabolic comorbidities, inflammation, and an overlap in genetics with Alzheimer disease, psoriasis patients might be at risk for cognitive dysfunction and dementia. Objective: To compare cognition, magnetic resonance imaging (MRI)–markers, and dementia risk in psoriasis and nonpsoriasis participants in the population-based Rotterdam Study. Methods: We identified 318 psoriasis and 9678 nonpsoriasis participants (mean age 66.1 years, 58% women). The association of psoriasis with cognitive function, mild cognitive impairment, and MRI-markers of brain damage was examined by linear and logistic regression. Dementia risk was calculated using Cox regression. Models were adjusted for age, sex, education, and cardiovascular risk factors. Results: Cognitive test scores and volumetric, microstructural, focal measures on brain MRI did not differ between psoriasis (28% systemic and ultraviolet treatment) and nonpsoriasis participants, and psoriasis was not associated with mild cognitive impairment (adjusted odd ratio 0.87, 95% confidence interval 0.53-1.43). During 115.000 person-years of follow-up, 810 incident dementia cases (15 among psoriasis patients) occurred. After adjusting for confounders, psoriasis was associated with a lower risk of developing dementia (adjusted hazard ratio 0.50, 95% confidence interval 0.28-0.91). Limitations: Limited dementia cases among psoriasis patients. Conclusion: In this population-based study, psoriasis was not associated with preclinical markers or higher dementia risk.