Atopic Dermatitis Associated With Higher Dementia Risk

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Researchers discovered a notable correlation between atopic dermatitis and dementia, according to data published in Acta Dermato-Venereologica.¹ Despite randomization analysis failing to identify a causal relationship between the 2 conditions, study results were able to inform future exploration into this correlation.

“Several well-established modifiable risk factors, such as lower education, hearing loss, traumatic brain injury, hypertension, diabetes, obesity, alcohol consumption, smoking, exposure to air pollution, physical inactivity, social isolation, and depression, contribute to the development of dementia,” wrote the authors. “Recent studies suggest that atopic dermatitis, a chronic and highly pruritic inflammatory skin disease adversely affecting quality of life, may serve as a potential risk factor for heightened dementia risk, possibly attributed to immunologic dysregulation and disturbance.”

Skin diseases like atopic dermatitis tend to cause significant reductions in patients’ quality of life. With quality of life also constituting both patients’ mental and physical health, researchers have already explored various relationships between skin disorders and mental health conditions.

One example of this was published in Clinical, Cosmetic and Investigational Dermatology. The study explored overall relationships between Alzheimer disease and a variety of skin conditions. Researchers concluded their study by identifying a relationship between Alzheimer disease and some skin disorders, including hidradenitis suppurativa, psoriasis, and skin cancer. However, the relationship between atopic dermatitis and Alzheimer disease was unclear.²

“A systematic review and meta-analysis comprehensively synthesizing the published cohort studies [has] not been published. In addition, there is a lack of recent literature employing Mendelian randomization [MR]—widely utilized for inferring causal associations—to evaluate the relationship between atopic dermatitis and dementia,” the authors continued.¹ “Therefore, our aim is to analyze the association between atopic dermatitis and dementia through a comprehensive approach, encompassing systematic review, meta-analysis, and MR.”

MR is a specified mode of reviewing current evidence that is robust, helping researchers gain an understanding of environmentally modifiable influences on specific diseases.³ In this case, researchers used MR to understand the causal relationship between atopic dermatitis and dementia. Furthermore, the MR was also designed to include dementia subtypes such as Alzheimer disease, vascular dementia, and cognitive performance as an immediate outcome.¹

After a comprehensive search of various cohort studies, researchers included a total of 5 papers that met the inclusion criteria for the meta-analysis. Among all 5 studies, the final analysis included a total of 12,576,235 individuals whose study results were all published from 2008 to 2023. All individuals included were at least 39 years of age.

“In the systematic review and meta-analysis, 5 longitudinal cohort studies indicated a significant association between atopic dermatitis and all-cause dementia,” they continued.¹ “Subgroup analyses revealed an adjusted hazard ratio of 1.18 for Alzheimer disease in patients with atopic dermatitis, and an adjusted hazard ratio of 1.37 for all-cause dementia in patients with moderate to severe atopic dermatitis. However, MR analysis showed no significant causal link between atopic dermatitis and dementia, Alzheimer disease, vascular dementia, or cognitive performance.”

Regarding the main outcome of patients’ dementia risk when living with atopic dermatitis, researchers discovered significant results for all-cause dementia—most notably Alzheimer disease. However, there was no causal relationship between the 2 conditions identified in MR, leading researchers to express caution before these results are interpreted.

“In summary, the systematic review and meta-analysis uncovered a notable correlation between atopic dermatitis and dementia, particularly Alzheimer disease,” they concluded.¹ “However, [MR] analysis failed to substantiate a significant causal relationship. Given the limitations of the study, the results require meticulous interpretation. Further research is imperative to unravel the intricate interplay between atopic dermatitis and dementia, considering potential demographic variables such as racial differences and medication influences.”

References

1. Gwak YS, Kim SY, Woo CE, et al. Association between atopic dermatitis and dementia: evidence from systematic review, meta-analysis, and Mendelian randomization. Acta Derm Venereol. 2025;105:adv41321. doi:10.2340/actadv.v105.41321

2. Zhang H, Zhang D, Tang K, et al. The relationship between Alzheimer's disease and skin diseases: a review. Clin Cosmet Investig Dermatol. 2021;14:1551-1560. doi:10.2147/CCID.S322530

3. Richmond RC, Davey Smith G. Mendelian randomization: concepts and scope. Cold Spring Harb Perspect Med. 2022;12(1):a040501. doi:10.1101/cshperspect.a040501

[This article was originally published by our sister publication, Drug Topics.]