Rosacea seems to independently predict the risk of developing Parkinson’s disease (PD), according to Danish research.
Of the 5.4 million adults analysed, 22,387 had PD and 68,053 had rosacea. Parkinson’s incidence was 3.54 and 7.62 per 10,000 person-years in the reference population and patients with rosacea respectively.
The adjusted risk of developing PD was 71 per cent higher in rosacea patients and doubled in those with ocular rosacea (incidence rate ratio [IRR] 2.03). Tetracyclines, a common rosacea treatment, slightly, but significantly, reduced PD risk (IRR 0.98 for each filled prescription).
Increased activity of members of a group of enzymes called matrix metalloproteinases (MMP) could link the pathogenesis of rosacea and PD. MMPs show increased activation and expression in rosacea, PD and other neurodegenerative disorders. On the other hand, tetracyclines reduce MMP expression.
Previous studies suggest other mechanisms that could contribute to both rosacea and PD, including small intestine bacterial overgrowth and H. pylori infection. The authors comment that “the clinical consequences of this association require further study”. In the meantime, focusing on neurologic symptoms in rosacea patients “may be warranted”.
(JAMA Neurol. doi:10.1001/aneurol.2016.0022)