The negative association between allergen-specific IgE and glioma risk has been previously identified,10 but this was not significant in another study.27 A reported history of atopy has also previously been associated with decreased glioma risk.4,8 However, a recent Mendelian randomization study only provided weak evidence for an association between atopy risk and glioma28; hence, the genetic component of this risk may be low. This evidence concerns the gene IGHE and glioma.