An increased focus on neurologic symptoms in patients with rosacea may be warranted, according to Danish researchers, who found a significantly increased risk of glioma associated with rosacea, in a nationwide study of Danish citizens.
The observational study followed 5,484,910 Danish adults from January 1997 through December 2011; 68,372 were diagnosed with rosacea, and the remaining 5,416,538 were the reference group. The incidence rate of glioma per 10,000 person-years (adjusted for age, sex, and socioeconomic status) was 3.34 in the reference population, but was 4.99 among those with rosacea, reported Dr. Alexander Egeberg of the department of dermatoallergology, Herlev and Gentofte University Hospital, University of Copenhagen, Hellerup, and his coauthors (JAMA Dermatol. 2016 Jan 27. doi: 10.1001/jamadermatol.2015.5549).
The adjusted incidence rate ratio (IRR) of glioma in patients with rosacea was 1.36 (P less than .001). When the researchers limited the analysis to patients who had been diagnosed by a hospital dermatologist, the adjusted IRR was 1.82. The results remained significant after sensitivity analyses and after adjustment for potential confounders.
Among the patients with rosacea, men had an increased risk of glioma, compared with women (an incidence rate per 10,000 person-years of 6.45 vs. 4.30), although “gliomas and rosacea were generally more common among women,” the authors reported.
The association might be partially mediated by mechanisms dependent on matrix metalloproteinases (MMPs), the authors said, referring to studies indicating that MMPs, in particular MMP-9, “play a pivotal role in rosacea and regulation of the invasiveness of malignant glioma cells.” While speculative, “mechanisms dependent on MMPs may contribute to the link between rosacea and the risk for glioma,” the investigators added.
An increased focus on neurologic symptoms such as headaches, memory loss, visual symptoms, cognitive decline, and personality changes in patients with rosacea “and timely referral to relevant specialists may be warranted,” they concluded.
Limitations of the study included the observational design, which cannot establish causation, the authors noted. Dr. Egeberg reported being a former employee of Pfizer; one coauthor reported receiving consultancy and/or speaker honoraria from Galderma. The study was supported by an unrestricted grant from the LEO Foundation and the Lundbeck Foundation and an unrestricted research scholarship from the Novo Nordisk Foundation.