Sex-related differences in composition of otosclerotic and unafflicted stapes

This research was undertaken to determine whether stapedial composition could be used to distinguish the sex of patients afflicted with otosclerosis and the sex of unafflicted controls. Energy dispersive-electron probe microanalyses (EDS/EPMA) of otosclerotic stapes from 10 male and 13 female patients were compared with analyses from four unafflicted men and five women. The composition of control stapes differed at p << 0.05 (discriminant analyses) from otosclerotic specimens. Thirteen elements analyzed are in two statistical categories: Group I: Ca, Cr, Fe, Zn, Mg, P, and S; and Group II: Al, K, Mn, Na, Si, and Ti. Elements of Group I distinguish unafflicted men from unafflicted women at a high level of significance (p << 0.05). The same group distinguished afflicted men from otosclerotic women at a lower level (p < or = 0.05), but only if comparisons are based on the single (rather than mean) maximum value of each trace element in each stapes, and only if both Cr and Zn are included in the group. Group I elements also distinguish control versus afflicted men and control versus afflicted women at p << 0.05. Group II elements do not distinguish any of the cohorts mentioned at p < or = 0.05, although they do more successfully classify control and afflicted women as to sex than they do men. They also more successfully predict the diseased status of afflicted men and women than the normal status of controls. The elements whose concentrations exhibit sex-related convergence in otosclerotic stapes are either fundamental constituents of stapedial hydroxyapatite in general or are specific activators of enzymes implicated in otosclerosis. Thus further investigation of the role of metal-potentiated enzymes in the origin of the disorder is warranted.