A German research team has found a significant association between psoriasis and all-cause dementia among patients living in that country. The study report appears in the .
Associations between chronic inflammation and forms of dementia including Alzheimer's disease (AD) have been the subject of robust research attention in recent years. Further, prior studies have found genetic links between psoriasis and AD. The current study was the first to seek out these associations in the German population.
The retrospective cohort study included 10,583 patients with psoriasis and 10,583 controls. After 15 years of follow-up, dementia developed in 22% of the patients with psoriasis and in 19.1% (P<0.001) of those without psoriasis. Overall, a significant link emerged between psoriasis and an increased dementia risk (HR 1.24, 95% CI 1.14-1.35 P<0.001).
The incidence rate of dementia in 1,000 person-years was 15.0 in psoriasis patients and 11.9 in the non-psoriasis cohort.
Karel Kostev, DrMS, is scientific principal for epidemiology research at IQVIA, a multinational health IT and clinical research firm. Kostev served as a co-author of the current paper and recently discussed its findings with the Reading Room. The exchange has been edited for length and clarity.
What was the impetus for this study, and what was the key knowledge gap it was designed to address?
Kostev: Our research team has been investigating dementia and its risk factors for many years. Rebecca Zingel, my colleague and co-author on this paper, dedicated her PhD thesis to dementia, and we both have investigated potential roles of cholesterol values, inflammatory bowel disease, and psoriasis.
A genetic association between psoriasis and Alzheimer's disease was previously found in a genetic epidemiological study, and the relationship between chronic psoriasis and dementia has been examined and summarized in different meta-analyses over the years.
However, no study in clinical practice had examined the relationship between psoriasis and dementia in Germany. This was the gap we wanted to address.
How would you summarize your main findings?
Kostev: We found a higher incidence rate of all-cause dementia in patients with psoriasis -- particularly in those with psoriatic arthritis (PsA) -- compared with patients who do not have psoriasis.
Psoriasis was associated with a 1.2-fold higher risk of developing dementia. The risk was 1.4-fold in patients with PsA, but this number was not statistically significant due to a lower number of patients.
What are the clinical implications for clinicians who treat people with psoriasis?
Kostev: Patients with psoriasis warrant a thorough investigation and need to be advised about the relationship between the disease and the development of dementia.
This is important from a certain age, let's say 50 and over. Patients, however, should not be afraid: a 1.2 times risk increase means only that if without chronic inflammatory diseases, 10 out of 100 people can get dementia in old age, while with psoriasis it is 12 out of 100, and thus only a little more.
Where is more study needed on this topic?
Kostev: We need studies on the protective effect of different biologics against dementia.
On the other hand, we are still hopeful that herbal preparations like ginkgo biloba can be helpful in the risk groups; studies on ginkgo biloba are also needed.
Study authors did not disclose any relevant financial relationships with industry.
Primary Source
Journal of Alzheimer's Disease Reports
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