Genetics have long been thought to play a role in rosacea, but researchers had yet to isolate their influence. In what may be the first study of rosacea to measure and define genetic and environmental contributions, Dr. Daniel Popkin, assistant professor of dermatology at Case Western Reserve University, and colleagues have found that genetics and environmental factors may contribute equally to the disorder.
To examine and isolate the potential genetic and environmental factors that may be involved in rosacea, the researchers studied a sample of 275 twin pairs (550 individuals) in whom at least one sibling has rosacea, recruited at the Twin Day Festival in Twinsburg, Ohio, near Cleveland. The study group included 233 pairs of identical twins and 42 pairs of nonidentical twins. Participants were scored based on the National Rosacea Society’s grading system and a physical examination by board-certified dermatologists. The researchers found that the disorder occurred significantly more often in both identical twins than in both members of a pair of fraternal (nonidentical) twins, and noted the association held true even after such common rosacea risk factors as age and skin type were accounted for, suggesting that genetics may play a substantial role in rosacea.
The researchers then evaluated factors such as gender, age, smoking/alcohol consumption history, heart health and lifetime sun exposure to determine the influence of certain environmental variables on the disease, and found that a higher rosacea score was positively associated with age and lifetime ultraviolet radiation exposure. They also found correlations with body mass index (BMI), smoking, alcohol consumption, cardiovascular issues and skin cancer.
"We found about a 50-50 contribution, nature versus nurture," said Popkin. "In our cohort, about 50 percent of the disease seems to be genetically driven, and the other half is environmental."
The researchers noted that although alcohol has been found to be a trigger of rosacea symptoms, it has not been identified as risk factor for development of the disorder. However, they did point out that the correlation between BMI (body mass index) and cardiovascular disease may be an opportunity for additional analysis. Recent studies have further highlighted a potential link between rosacea and the increased risk of cardiovascular disease.