IL4 and asthma: Although no study was available before for the association IL‐4 polymorphism with steroid‐induced ONFH, this SNP has been associated with autoimmune hepatitis (Yousefi et al., 2016), osteoarthritis (Vargiolu et al., 2010), asthma (Zhang et al., 2007), chronic periodontitis (Chen, Zhang, & Wang, 2016), and other clinical features (Wadley et al., 2013).