Environmental risk factors in JIIMs are not as well understood, and most efforts have focused on the potential role of infections in their aetiologies. Studies of cohorts of patients with JDM indicate that respiratory and gastrointestinal infections may be temporally associated with the onset of JIIM [16, 17] . Prior studies of other autoimmune diseases suggest differences in environmental risk factors in different phenotypes [9] , but the relationship between environmental risk factors and phenotypes has not been examined in the JIIMs [16, 17] .