Alopecia areata may increase dementia risk

Patients with alopecia areata had increased risk for dementia, according to a nationwide cohort study published in Journal of Clinical Psychiatry.

“Dementia, and [Alzheimer’s disease] specifically, has been shown to include an inflammatory component that may share some of the same mediators seen in [alopecia areata], such as interleukin-1 (IL-1), IL-6 and tumor necrosis factor– (TNF-),” Cheng-Yuan Li, MD, MSc, of the department of dermatology at Taipei Veterans General Hospital in Taiwan, and colleagues wrote. “In addition, the great negative psychosocial impact of [alopecia areata] might further lead to physical inactivity or less social engagement, which are significant risk factors of dementia, according to one meta-analysis. Therefore, it is reasonable to hypothesize that [alopecia areata] might be associated with an increased risk of dementia.”

Using the Taiwan National Health Insurance Research Database, the investigators analyzed data of 2,534 patients aged 45 years or older with alopecia areata according to ICD-9 criteria and 25,340 controls matched by age, sex, residence, income, dementia-related comorbidities, systemic steroid use and annual outpatient visit. They drew data from 1998 to 2011 to examine subsequent dementia between enrollment and the end of 2013. They controlled for potential confounders and then applied stratified Cox regression analysis on each matched pair to investigate the dementia risk between the alopecia areata and control groups.

Results showed increased risk for developing any dementia among patients with alopecia areata (adjusted HR = 3.24; 95% CI, 2.14-4.90), AD (aHR = 4.34; 95% CI, 1.45-12.97) and unspecified dementia (aHR = 3.36; 95% CI, 2.06-5.48) compared with the control cohort. After stratifying analysis by age and sex, the researchers observed increased risks for any dementia and unspecified dementia among those younger than 65 years and those 65 years or older, as well as among both sex groups. They also noted increased risk for AD among men and among those with age at dementia onset of 65 years or older. Findings appeared consistent after sensitivity analyses that excluded the first year or first 3 years of observation.

“Patients with [alopecia areata] who were [45 years or older] had an increased risk of developing any dementia, AD and unspecified dementia in comparison to the control group,” Li and colleagues wrote. “Further studies are required to confirm our findings and clarify the possible pathophysiology between [alopecia areata] and dementia risk.”