According to a new study people with rosacea – the facial
redness affecting millions of people – are at an increased risk of developing
dementia, particularly Alzheimer's disease, compared with people without the
condition. The study also found that older patients and patients who were
diagnosed by a hospital dermatologist were at the highest risk of developing
Alzheimer’s.
However, the researchers were quick to point out that people
with rosacea should not be overly concerned about the finding.
“It is important for patients to remember that having
rosacea does not guarantee that they will develop Alzheimer’s disease,” said lead
author Dr. Alexander Egeberg of the department of dermato-allergology at Herlev
and Gentofte Hospital, in Copenhagen, Denmark.
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“In fact, while the risk in rosacea patients may be slightly
increased compared with the general population, the absolute risk [to any one
patient] is still quite low,” he said.
Rosacea is very common, where some estimates suggest up to 1
in 10 people may have it. According to the National Rosacea Society,
approximately 16 million Americans suffer from it. Around 1 in every 600 people
in the UK are diagnosed with the condition each year. It most commonly affects
people with fair skin, but can also occur in people of Asian and
African origin. The condition is often mistaken for eczema, acne, or some other
skin condition. Rosacea occurs in both men and women, but tends to be more
common in women. Most cases are first diagnosed in people aged 30 to 50. There
are no cures for the condition, but some medicines can alleviate symptoms.
The study was conducted by the team because there is
evidence rosacea is linked with higher levels of certain proteins that have
also been implicated in various neurological disorders, such as Alzheimer's
disease and other forms of dementia. The proteins in question here are matrix
metalloproteinases and antimicrobial peptides.
For the new study, Dr. Egeberg’s team analyzed data from the
Danish nationalhealth registry system covering the period 1997-2012. The nation’s
entire population – nearly 6 million men and women – were included, out of whom
83,500 had rosacea.
Individuals were followed until December 31, 2012,
migration, a diagnosis of dementia, or death from any cause, whichever came
first. Altogether, just over 99,000 developed dementia, including around 29,000
who were diagnosed with Alzheimer's disease.
After analysis, researchers found that people with rosacea
had a 7% increased risk of dementia and a 25% increased risk of Alzheimer’s,
compared with patients who did not have the skin condition. Older people were
at higher risk.
The results also varied between men and women, where women
with rosacea were at 28% increased risk of Alzheimer’s and men were at 16%
increased risk.
For women, the raised risk of Alzheimer's linked to rosacea
was 28 percent, whereas for men with the skin disorder it was 16 percent.
When the analysis was limited to cases of rosacea that had
been diagnosed by a hospital dermatologist, the researchers found the increased
risk of dementia was 42%, while the risk was 92% for Alzheimer’s disease.
Dr. Egeberg says:
"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."
"Indeed," he continues, "emerging evidence
suggests that rosacea may be linked with neurological disorders including
Parkinson's disease and now also Alzheimer's disease."
He says that the risk may be explained by certain underlying
mechanisms shared by rosacea and Alzheimer's disease, but it is no known
whether one causes the other.
The team suggests doctors should look out for symptoms of
cognitive impairment in older patients with rosacea, and that only further
studies can affirm if treating rosacea may also improve patients' risk of
developing dementia.
The findings are published in the Annals of Neurology, a journal of the American
Neurological Association and Child Neurology Society.
