Yoshii E, Yamana H, Ono S, et al. - The association between allergic or autoimmune diseases and the incidence of endometriosis was examined via analyzing data retrieved from a large-scale health insurance claims database in Japan. Overall 30,516 cases with endometriosis and 120,976 control participants were analyzed. An increased incidence of endometriosis was observed in correlation with several allergic diseases, like allergic rhinitis, urticaria, and allergic conjunctivitis. Patients with rheumatoid arthritis also showed a higher incidence.