“Psoriasis has been linked with a variety of systemic disorders, including cardiovascular (CV) conditions, which may predispose patients to developing dementia,” explains Megan Lam, BSc. “While the etiologies of many dementias are poorly understood, neuroinflammation and vasculopathy are hypothesized to play a role. A comprehensive understanding of risks and comorbidities associated with a chronic inflammatory condition such as psoriasis is important for clinicians and patients alike.”

For a paper published in the Journal of the American Academy of Dermatology, Lam and colleagues conducted a systematic review and meta-analysis to better characterize the association between psoriasis and dementia. They included cross-sectional, case control, and cohort studies examining the incidence or prevalence of dementia among adults with psoriasis compared with adults without psoriasis. “We included four studies in our meta-analysis, pooling hazard ratios (HRs) for overall dementia, vascular dementia, and dementia of the Alzheimer’s type to determine the overall risk of each type of dementia in patients with psoriasis,” she says.

Deficiencies in Executive Functioning

The study team’s findings not only support an association between psoriasis and dementia, but also characterize the extent of this association and the type of dementia to which patients with psoriasis may be predisposed. Overall, dementia is generally linked with psoriasis, with a pooled HR of 1.13 (95% CI, 0.91-1.41), but with substantial heterogeneity across three studies (I2 = 82%). “Based on these findings, it is possible that inflammatory skin diseases may lead to systemic changes and vice versa,” adds Lam. “Our study showed that vascular dementia had the greatest association with psoriasis, in line with previous research. Individuals with psoriasis were 1.43 times more likely to have vascular dementia, compared with those without psoriasis (Figure).” Dementia of the Alzheimer’s type was also found to have a significant association with psoriasis (HR, 1.08).

Vasculopathy associated with psoriasis, including arterial stiffness and impaired endothelial function, may predispose patients with psoriasis to dementia, particularly vascular dementia, according to the study authors. “Oxidative stress and proinflammatory cytokines, which are elevated in patients with psoriasis, may impair neurogenesis and synaptic plasticity, promoting neurodegenerative processes and contributing to cognitive decline,” they write. “Individuals with psoriasis have been reported to have deficiencies in executive functioning, suggesting some involvement of the prefrontal cortex.”

Managing & Reducing CV Risk

Preventative health measures and lifestyle changes to reduce dementia risk may be of particular benefit to patients with psoriasis, says Lam. “In recognizing a potentially elevated risk for vascular dementia in this patient population, clinicians should emphasize the importance of managing and reducing CV risk factors,” she says. “Patients already at high risk may benefit from increased observation for the development of dementia.”

Lam and colleagues note the need for additional research on the impacts of psoriatic inflammation and associated predisposition to vascular disease on dementia risk and cognition. “This investigation has the potential to help gain more understanding of the pathogenesis of both diseases, as well as to better inform patients and clinicians alike,” Lam explains. “Characterizing how inflammatory cutaneous conditions may lead to downstream, and in extension, systemic effects, is critical.”