APOE and Schnyder corneal dystrophy: In analyses stratified by APOE ε4 allele carrier status, there was a suggestion that the risk of SCD was significantly elevated among women who were non-carriers of the APOE ε4 allele, but the p-for-interaction was not significant in either female cohort (p-interaction = 0.98 in NHS and 0.08 in NHS II) (Table 4).