Sex and family history differences in Aβ and tau vulnerability in preclinical Alzheimer’s disease

Abstract

AbstractBackgroundFemales and individuals with a family history (FH) of Alzheimer’s disease (AD) are considered at higher risk of sporadic AD. However, how sex and maternal/paternal heredity affects in vivo AD biomarkers is not well understood. Our objectives were to 1) assess if females or individuals with a first‐degree maternal FH of AD accumulate amyloid‐beta (Aβ) and/or tau faster than males or individuals with a first‐degree paternal FH of AD and 2) assess if both could influence the rate of Aβ driving tau in preclinical AD.MethodTwo hundred and thirty‐five older adults (age 68.3 ± 5.1 years, 69.8% female) from the PREVENT‐AD cohort, cognitively unimpaired at baseline, underwent [18F]‐NAV4694 and [18F]‐AV1451 positron emission tomography (PET) scans. Longitudinal PET scans were available for 106 individuals (4.3 ± 0.4 years follow‐up). We extracted and averaged the standard uptake value ratio (SUVr) in fronto‐parietal regions for Aβ and in temporal regions for tau. We performed t‐tests and ANOVA models to assess sex or maternal/paternal FH (FHsex) differences in Aβ and tau burden or annual change. We then performed linear regression models with an interaction term between Aβ and sex (or Aβ and FHsex) on tau burden and annual change, plus additional models to adjust for age and education.ResultSex and FHsex differences on Aβ and tau burden or annual rate of change did not reach significance although females tended to have higher tau SUVr at baseline (p = 0.053) (Figure 1 & 2). We found an interaction between Aβ and sex (𝛽 = ‐0.13, p = 0.008), and between Aβ and FHsex (𝛽 = 0.11, p = 0.03), on tau at baseline (Figure 3) suggesting that, for the same level of Aβ burden, females and individuals with paternal FH of AD had higher tau burden than males and individuals with maternal FH of AD. Results were similar when adjusted for age and education.ConclusionFemales and individuals with a paternal FH of AD might need less Aβ before developing AD‐related tau, but did not accumulate tau faster. Identifying individuals more vulnerable to AD pathology, by disentangling sex‐specific effects, would help to design personalized interventions for AD.