The Association between Sex and Risk of Alzheimer’s Disease in Adults with Down Syndrome

Background: Sex differences in the risk of Alzheimer’s Disease (AD) in adults with Down Syndrome (DS) have not been extensively investigated, and existing studies have found conflicting results. This study examined the effect of sex on the risk of AD in adults with DS, adjusted for covariates. Methods: Adults with DS were assessed longitudinally for the development of AD. Competing risk survival analyses were used to determine the effect of sex alone and after adjustment for APOE-ε4 status, ethnicity, and level of intellectual disability (ID). Results: Sex differences were significant only in adults over 60 years of age, where men with DS were 6.32 (95% CI: 2.11–18.96, p < 0.001) times more likely to develop AD compared with age-matched women with DS. Conclusions: There is an age-associated effect of sex on the risk of AD, with men over 60 years old having six times the risk of AD compared with age-matched women, independent of APOE-ε4 status, ethnicity, and level of ID.