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Rosacea may indicate increased risk for Parkinson’s disease

Researchers identified an increased risk for Parkinson’s disease in patients with rosacea, according to data published in JAMA Neurology.

This risk further increased in patients specifically with ocular rosacea, according to Alexander Egeberg, MD, PhD, department of dermato-allergology, Herlev and Gentofte Hospital, University of Copenhagen, and colleagues.

They suggested that the association may be due to elevated matrix metalloproteinase activity.

"Rosacea skin shows an upregulation of various cytokines, in particular, antimicrobial peptides, and displays increased activation and expression of matrix metalloproteinases," they wrote. "There is a critical interplay between [matrix metalloproteinases] and antimicrobial peptides in rosacea skin; for example, matrix metalloproteinase-9 activates the kallikrein 5 serine protease, leading to generation of LL-37 (the cathelicidin-derived antimicrobial peptide), which may then further stimulate inflammation."

Egeberg and colleagues continued: "Matrix metalloproteinases have also been implicated in the pathogenesis of Parkinson’s disease and other neurodegenerative disorders; in experimental models of Parkinson’s disease, matrix metalloproteinase-3 and matrix metalloproteinase-9 levels are increased and contribute to dopaminergic neuronal loss."

The researchers conducted a nationwide cohort study of Danish citizens aged 18 years and older via the Danish Civil Registration System, which connects people to various registries nationwide. The cohort consisted of 5,472,745 participants who were identified and tracked between January 1997 and December 2011.

Data showed that 22,387 participants were diagnosed with Parkinson’s disease during the study period and 68,053 participants were registered as having rosacea.

Incidence rates of Parkinson’s disease per 10,000 person-years were 3.54 (95% CI, 3.49-3.59) for the reference population and 7.62 (95% CI, 6.78-8.57) for patients with rosacea.

Egeberg and colleagues stated that adjusted incidence rate ratio for Parkinson’s disease was 1.71 (95% CI, 1.52-1.92) for patients with rosacea compared with the reference population. There was an increased risk for Parkinson’s disease in patients with ocular rosacea (adjusted IRR = 2.03; 95% CI, 1.67-2.48). Participants who were prescribed tetracycline demonstrated a reduced risk of Parkinson’s disease (adjusted IRR = 0.98; 95% CI, 0.97-0.99).

"We observed a significantly increased risk of new-onset Parkinson’s disease in patients with rosacea and a younger age at Parkinson’s disease onset in these individuals," the researchers concluded. "The results remained consistent in fully adjusted models and in sensitivity analyses. Analyses aimed at evaluating the risk of Parkinson’s disease in rosacea subtypes showed a tendency toward an increased risk in patients with ocular rosacea. In addition, regardless of the presence of rosacea, a decreased risk of Parkinson’s disease was found in individuals who had filled prescriptions for tetracyclines." – by Chelsea Frajerman Pardes

Disclosures: Egeberg reported being employed by Pfizer Inc. at the time of the study. Please see the full study for a complete list of all other authors' relevant financial disclosures.