A new study has uncovered an increased risk of dementia--in particular Alzheimer's disease--in patients with rosacea. Importantly, the risk was highest in older patients and in patients where rosacea was diagnosed by a hospital dermatologist. The findings are published in the Annals of Neurology, a journal of the American Neurological Association and Child Neurology Society.

Rosacea is a common chronic inflammatory skin disorder that is characterized by elevated expression of certain proteins--including matrix metalloproteinases and antimicrobial peptides--that are also involved in various neurodegenerative disorders such as Alzheimer's disease and other forms of dementia. Because of this potential link, a team led by Alexander Egeberg, MD, PhD, of University of Copenhagen, investigated the association between rosacea and dementia in Danish registers.

There were 5,591,718 Danish citizens aged ?18 between 1997 to 2012, including 82,439 patients with rosacea. Individuals were followed until December 31, 2012, migration, a diagnosis of dementia, or death from any cause, whichever came first. A total of 99,040 individuals developed dementia, of which 29,193 were diagnosed with Alzheimer's disease. After adjustments for potential confounding factors, patients with rosacea had a 7 percent increased risk of dementia and a 25 percent increased risk of Alzheimer's disease compared with individuals without rosacea. Stratified by sex, women had a 28 percent increased risk of Alzheimer's disease and men had a 16 percent increased risk if they had rosacea. When results were stratified by age at study entry, the risk of Alzheimer's disease was only significantly increased in individuals ?60 years (who had a 20 percent increased risk). When analyses were limited to patients with a hospital dermatologist diagnosis of rosacea only, the increased risks of dementia and Alzheimer's disease were 42 percent and 92 percent, respectively.

"A subtype of patients have prominent neurological symptoms such as burning and stinging pain in the skin, migraines, and neuropsychiatric symptoms, suggesting a link between rosacea and neurological diseases," explained Dr. Egeberg. "Indeed, emerging evidence suggests that rosacea may be linked with neurological disorders including Parkinson's disease and now also Alzheimer's disease. There are certain mechanistic overlaps between rosacea and Alzheimer's disease that may explain the observed association, albeit the pathogenic links between these conditions are still unclear."

Dr. Egeberg noted that it is important for patients to remember that having rosacea does not necessarily mean that they will develop dementia; however, the results may provide new insights into the link between the skin and neurodegenerative disorders. Further research is warranted to examine whether treating rosacea may also modify patients' risk of developing dementia.

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Full citation: "Patients with rosacea have increased risk of dementia." Alexander Egeberg, Peter R. Hansen, Gunnar H. Gislason, and Jacob P. Thyssen. Annals of Neurology; Published Online: April 28, 2016 (DOI:10.1002/ana.24645).

URL Upon Publication: http://doi. wiley. com/ 10. 1002/ ana. 24645

Author Contact: Lead author, Dr. Alexander Egeberg from the University of Copenhagen at alexander.egeberg@gmail.com.

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Annals of Neurology, the official journal of the American Neurological Association and the Child Neurology Society, publishes articles of broad interest with potential for high impact in understanding the mechanisms and treatment of diseases of the human nervous system. All areas of clinical and basic neuroscience, including new technologies, cellular and molecular neurobiology, population sciences, and studies of behavior, addiction, and psychiatric diseases are of interest to the journal. The journal is published by Wiley on behalf of the American Neurological Association and Child Neurology Society. For more information, please visit http://onlinelibrary. wiley. com/ journal/ 10. 1002/ ana .

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