Clarifying relationships between amyloid, tau, and cognition is crucial to understanding dementia risk, but has been mainly performed in non-Hispanic White (NHW) participants. It is unknown whether fi Show more
Clarifying relationships between amyloid, tau, and cognition is crucial to understanding dementia risk, but has been mainly performed in non-Hispanic White (NHW) participants. It is unknown whether findings are generalizable to other ethnoracial groups. We evaluated relationships between amyloid-β (Aβ) positivity, apolipoprotein E allele (APOE) ε4, tau-positron emission tomography (PET) Black (β = 0.28, p < 0.001) and Hispanic (β = 0.34, p < 0.001) participants had higher medial temporal lobe (MTL) tau than NHW participants; however, findings were attenuated when accounting for choroid plexus off-target binding. Hispanic participants showed higher tau in lateral temporal regions compared to NHW and Black participants; however, reducing meningeal off-target binding through erosion demonstrated similar lateral temporal tau across groups. Factors other than amyloid and tau may impact cognition in Black participants. PI2620 off-target ethnoracial differences should be investigated. Show less
Ambient air pollution exposures increase risk for Alzheimer's disease (AD) and related dementias, possibly due to structural changes in the medial temporal lobe (MTL). However, previous MRI studies ex Show more
Ambient air pollution exposures increase risk for Alzheimer's disease (AD) and related dementias, possibly due to structural changes in the medial temporal lobe (MTL). However, previous MRI studies examining exposure effects on the MTL were cross-sectional and mostly focused on the hippocampus, yielding mixed results. We addressed these limitations using longitudinal data collected from 653 cognitively unimpaired community-dwelling women from the Women's Health Initiative Memory Study with two MRI scans (M Show less
Obesity is a crucial public health issue in developed countries, with implications for cardiovascular and brain health as we age. A number of commonly-carried genetic variants are associated with obes Show more
Obesity is a crucial public health issue in developed countries, with implications for cardiovascular and brain health as we age. A number of commonly-carried genetic variants are associated with obesity. Here we aim to see whether variants in obesity-associated genes--NEGR1, FTO, MTCH2, MC4R, LRRN6C, MAP2K5, FAIM2, SEC16B, ETV5, BDNF-AS, ATXN2L, ATP2A1, KCTD15, and TNN13K--are associated with white matter microstructural properties, assessed by high angular resolution diffusion imaging (HARDI) in young healthy adults between 20 and 30 years of age from the Queensland Twin Imaging study (QTIM). We began with a multi-locus approach testing how a number of common genetic risk factors for obesity at the single nucleotide polymorphism (SNP) level may jointly influence white matter integrity throughout the brain and found a wide spread genetic effect. Risk allele rs2815752 in NEGR1 was most associated with lower white matter integrity across a substantial portion of the brain. Across the area of significance in the bilateral posterior corona radiata, each additional copy of the risk allele was associated with a 2.2% lower average FA. This is the first study to find an association between an obesity risk gene and differences in white matter integrity. As our subjects were young and healthy, our results suggest that NEGR1 has effects on brain structure independent of its effect on obesity. Show less