Sex differences in risk of Alzheimer's disease in adults with Down syndrome

INTRODUCTION: Adults with Down syndrome (DS) older than 40 have Alzheimer's disease (AD) neuropathology and high risk for dementia, but little is known about the relationship of sex to AD risk in this population. METHODS: Using nonparametric methods and Cox proportional hazards models we analyzed differences in incidence of dementia, by sex, presence of an apolipoprotein E (APOE) ε4 or ε2 allele, and dementia duration and decline in 246 adults over 40 with DS. RESULTS: There was no significant sex difference in risk of AD or rate of cognitive decline. APOE ε4 allele significantly increased risk of AD irrespective of sex. No significant interactions were found between sex and APOE status on AD risk. Among those who died, dementia duration was significantly longer in women. DISCUSSION: This study showed no effect of sex nor interaction between sex and APOE for risk of AD in adults with DS; however, women had longer dementia duration.