Sleep complaints and genetic risk of Alzheimer's disease in older women: associations with memory and tau deposition.

BACKGROUND

Emerging evidence point to a bidirectional relationship between sleep disturbances and Alzheimer's disease (AD). Poor sleep may be an overlooked risk factor for older women, who are disproportionately affected by AD and report worse subjective sleep quality than men. High genetic AD risk-characterized by the polygenic hazard score (PHS), including apolipoprotein (APOE) ε4 carriership-may further compound the effects of disrupted sleep on AD, particularly for older women.

OBJECTIVE

This study examined the moderating effect of genetic AD risk on subjective sleep as it related to memory and tau burden in a sample of older women.

PARTICIPANTS

The sample consisted of older women (≥65 years old) from the Women Inflammation Tau Study.

MEASUREMENT: Participants completed the Pittsburgh Sleep Quality Index (PSQI), Rey Auditory Learning Test, and Brief Visuospatial Memory Test-Revised. They also underwent [18]F-MK6240 positron emission tomography. Tau burden was calculated in composite regions across Braak stages. Genetic risk groups were characterized by PHS stratified at the 75th percentile. PSQI global score × PHS group interactions on memory composite scores (N = 69) and tau burden (N = 63) were examined.

RESULTS

PSQI global score × PHS group interactions were observed on visual memory and pathological tau in Braak regions III/IV (ps<0.10). Poorer subjective sleep was associated with worse visual memory and greater limbic tau deposition only among higher genetic risk women (ps<0.04). No significant associations were observed for verbal memory or tau in Braak regions I/II or V/VI.

CONCLUSION

Older women with elevated genetic AD risk and subjective sleep difficulties may be at greater risk for visual memory deficits and tau burden in regions affected in early AD. This suggests that sleep complaints may represent a promising AD risk factor. Improving sleep may be a potential intervention target for AD mitigation and prevention, particularly for older women.