A total of 275 twin pairs (550 individuals) participated in the study. There were 233 identical twin pairs with a mean rosacea score of 2.46 and 42 fraternal twin pairs with a mean rosacea score of 0.75.
There was a higher association of NRS scores between identical versus fraternal twins (r = 0.69 versus r = 0.46, P = 0.04), demonstrating a genetic contribution.
The study found that approximately half of the contribution to the NRS score could be accounted for by genetics and the other half by environment. Correlations were found between rosacea and UV radiation exposure, alcohol, smoking, skin cancer history, cardiac comorbidity and age.
Aldrich N, Gerstenblith M, Fu P et al. JAMA Dermatol August 26, 2015; doi:10.1001/jamadermatol.2015.2230