Klaus P. Ebmeier
Profile Url: klaus-p--ebmeier
Researcher at University of Oxford
0
0
0
Video Abstract (AI generated)
Paper
Preprint
Supplementary
Brain age is an influential index for quantifying brain health, assumed partially to reflect the rate of brain aging. We explicitly tested this assumption in two large datasets and found no association between cross-sectional brain age and steeper brain decline. Rather, brain age in adulthood was associated with early-life influences indexed by birth weight and polygenic scores. The results call for nuanced interpretations of cross-sectional indices of the aging brain.
0
0
0
Video Abstract (AI generated)
Paper
Preprint
Supplemental Information
Background. To test the hypothesis that worse self-reported sleep relates to memory decay and reduced hippocampal integrity as indexed by increased intra-hippocampal water diffusion, and that the relations are stronger in the presence of β-amyloid (Aβ) accumulation, a marker of Alzheimer's disease (AD) pathology. Methods. Two-hundred and forty-three cognitively healthy participants, aged 19-81 years, completed the Pittsburgh Sleep Quality Index, and 2 diffusion tensor imaging sessions, on average 3 years apart, allowing measures of decline in hippocampal microstructural integrity as indexed by increased mean diffusivity. We measured memory decay using delayed recall from the California Verbal Learning Test. 18F-Flutemetamol positron emission tomography, in 108 participants above 44 years of age, yielded 23 Aβ positive. Genotyping enabled controlling for APOE ϵ4 status, and polygenic scores for sleep efficiency and AD. Results. Worse global sleep quality and sleep efficiency related to more rapid reduction in hippocampal microstructural integrity over time. Focusing on sleep efficiency, the relation was stronger in presence of Aβ accumulation. Sleep efficiency related to memory decay indirectly via hippocampal integrity decline. The results were not explained by genetic risk for sleep efficiency and AD. Conclusions. Poor self-reported sleep efficiency related to decline in hippocampal integrity, especially in the presence of Aβ accumulation. Poor sleep and hippocampal microstructural decline may partly explain memory decline in older adults with Aβ pathology. The relationships were not explained by genetic risk. Poor self-reported sleep efficiency might constitute a risk factor for AD, although the causal mechanisms driving the of observed associations remain unknown. ### Competing Interest Statement The authors have declared no competing interest.
0
0
0
Video Abstract (AI generated)
Paper
Preprint
Supplemental Information
Socio-economic status (SES) has been proposed to have facilitating and protective effects on brain and cognition. Here we show that relationships between SES, brain volumes and general cognitive ability differ significantly across European and US cohorts (4-97 years, N ≈ 500,000; 54,000 with brain imaging). Education was positively related to intracranial (ICV) and total brain gray matter (GM) volume. Income was related to ICV, but not GM. Relationships varied significantly across samples, and SES was more strongly related to brain and cognition in US than European cohorts. Differences in neuroanatomical volumes explained part of the SES-cognition relationships. SES was more strongly related to ICV than to GM, implying that SES-cognition relations in adulthood are less likely grounded in neuroprotective effects on GM volume in aging. Rather, a relationship may be established early in life. The findings underscore that SES has no uniform association with, or impact on, brain and cognition. ### Competing Interest Statement Christian A Drevon is a cofounder, stock-owner, board member and consultant in the contract laboratory Vitas AS, performing personalized analyses of blood biomarkers. None of the other authors declare competing interests.