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Item Evaluating the association of APOE genotype and cognitive resilience in SuperAgers(medRxiv, 2025-01-07) Durant, Alaina; Mukherjee, Shubhabrata; Lee, Michael L.; Choi, Seo-Eun; Scollard, Phoebe; Klinedinst, Brandon S.; Trittschuh, Emily H.; Mez, Jesse; Farrer, Lindsay A.; Gifford, Katherine A.; Cruchaga, Carlos; Hassenstab, Jason; Naj, Adam C.; Wang, Li-San; Johnson, Sterling C.; Engelman, Corinne D.; Kukull, Walter A.; Keene, C. Dirk; Saykin, Andrew J.; Cuccaro, Michael L.; Kunkle, Brian W.; Pericak-Vance, Margaret A.; Martin, Eden R.; Bennett, David A.; Barnes, Lisa L.; Schneider, Julie A.; Bush, William S.; Haines, Jonathan L.; Mayeux, Richard; Vardarajan, Badri N.; Albert, Marilyn S.; Thompson, Paul M.; Jefferson, Angela L.; Alzheimer’s Disease Neuroimaging Initiative (ADNI); Alzheimer’s Disease Genetics Consortium (ADGC); The Alzheimer’s Disease Sequencing Project (ADSP); Crane, Paul K.; Dumitrescu, Logan; Archer, Derek B.; Hohman, Timothy J.; Gaynor, Leslie S.; Radiology and Imaging Sciences, School of MedicineImportance: "SuperAgers" are oldest-old adults (ages 80+) whose memory performance resembles that of adults in their 50s to mid-60s. Factors underlying their exemplary memory are underexplored in large, racially diverse cohorts. Objective: To determine the frequency of APOE genotypes in non-Hispanic Black and non-Hispanic White SuperAgers compared to middle-aged (ages 50-64), old (ages 65-79), and oldest-old (ages 80+) controls and Alzheimer's disease (AD) dementia cases. Design: This multicohort study selected data from eight longitudinal cohort studies of normal aging and AD. Setting: Variable recruitment criteria and follow-up intervals, including both population-based and clinical-based samples. Participants: Inclusion in our analyses required APOE genotype, that participants be age 50+, and are identified as either non-Hispanic Black or non-Hispanic White. In total, 18,080 participants were included in the present study with a total of 78,549 datapoints. Main outcomes and measures: Harmonized, longitudinal memory, executive function, and language scores were obtained from the Alzheimer's Disease Sequencing Project Phenotype Harmonization Consortium (ADSP-PHC). SuperAgers, controls, and AD dementia cases were identified by cognitive scores using a residual approach and clinical diagnoses across multiple timepoints when available. SuperAgers were compared to AD dementia cases and cognitively normal controls using age-defined bins (middle-aged, old, oldest-old). Results: Across racialized groups, SuperAgers had significantly higher proportions of APOE-ε2 alleles and lower proportions of APOE-ε4 alleles compared to cases. Similar differences were observed between SuperAgers and middle-aged and old controls. Non-Hispanic White SuperAgers had significantly lower proportions of APOE-ε4 alleles and significantly higher proportions of APOE-ε2 alleles compared to all cases and controls, including oldest-old controls. In contrast, non-Hispanic Black SuperAgers had significantly lower proportions of APOE-ε4 alleles compared to cases and younger controls, and significantly higher proportions of APOE-ε2 alleles compared only to cases. Conclusions and relevance: In the largest study to date, we demonstrated strong evidence that the frequency of APOE-ε4 and -ε2 alleles differ between non-Hispanic White SuperAgers and AD dementia cases and cognitively normal controls. Differences in the role of APOE in SuperAging by race underlines distinctions in mechanisms conferring resilience across race groups given likely differences in genetic ancestry.Item Genetic and Sex Associations with Earlier Estimated Onset of Amyloid Positivity from over 4000 Harmonized Positron Emission Tomography Images(Wiley, 2025-01-09) Castellano, Tonnar; Wang, Ting Chen; Nolan, Emma; Archer, Derek B.; Cody, Karly; Harrison, Theresa M.; Wu, Yiyang; Durant, Alaina; Janve, Vaibhav A.; Engelman, Corinne D.; Jagust, William J.; Albert, Marilyn S.; Johnson, Sterling C.; Resnick, Susan M.; Sperling, Reisa A.; Bilgel, Murat; Saykin, Andrew J.; Vardarajan, Badri N.; Mayeux, Richard; Betthauser, Tobey J.; Dumitrescu, Logan C.; Mormino, Elizabeth; Hohman, Timothy J.; Koran, Mary Ellen I.; Radiology and Imaging Sciences, School of MedicineBackground: New techniques have been developed to estimate the age when someone converted to amyloid positivity (EAOA) from PET, oftentimes offering information about a participant decades before they joined a research study. EAOA is variable across populations but we do not know the causes for these differences. This study aims to validate APOE associations with EAOA and explore genetic and sex‐based factors with EAOA. Methods: Data from six cohorts were analyzed. Our analysis included 4220 non‐Hispanic white people (57.6% women; 86.7% cognitively unimpaired at baseline scan). Amyloid PET data were harmonized using gaussian mixture models. EAOA was calculated using the sampled iterative local approximation (SILA) algorithm. Sex differences in EAOA were compared using t‐tests amongst amyloid positive individuals. A genome‐wide association study of EAOA was performed. Gene analyses were conducted using MAGMA. Results: Average EAOA was 81.1 years across all individuals regardless of amyloid status. APOE e2 homozygotes had slightly later EAOA than e3/e3 homozygotes. APOE e4 homozygotes converted to amyloid positivity 8.2 years before e3/e4 heterozygotes and over two decades earlier than e3 homozygotes. APOE e2/e4 converted to positivity roughly three years later than e3/e4 and nearly ten years earlier than e3 homozygotes. APOE genotype differences in EAOA described were statistically significant (p < .01). There were significant sex differences between men and women when examining amyloid positivity. Men converted to amyloid positivity over 2 years later than women (65.3 vs 63.2 years, p=3.23x10‐5). The rs12981369 polymorphism in ABCA7 was associated with EAOA (β = 2.14, p=9.27×10−9). Brain eQTL databases indicate associations between rs12981369 and gene expression of ABCA7. Gene‐level analyses revealed significant associations for ABCA7, HMHA1, and KIF13B. Conclusion: This study further describes the role of APOE and reveals roles for ABCA7 and KIF13B on amyloid onset. We identified a novel variant on chromosome 19 correlating with later amyloid onset conversion and highlight important differences between sexes. These findings highlight EAOA as a powerful endophenotype of AD and offer insights into potential drug‐targetable mechanisms for early AD intervention.Item Leveraging longitudinal diffusion MRI data to quantify differences in white matter microstructural decline in normal and abnormal aging(bioRxiv, 2023-05-18) Archer, Derek B.; Schilling, Kurt; Shashikumar, Niranjana; Jasodanand, Varuna; Moore, Elizabeth E.; Pechman, Kimberly R.; Bilgel, Murat; Beason-Held, Lori L.; An, Yang; Shafer, Andrea; Ferrucci, Luigi; Risacher, Shannon L.; Gifford, Katherine A.; Landman, Bennett A.; Jefferson, Angela L.; Saykin, Andrew J.; Resnick, Susan M.; Hohman, Timothy J.; Alzheimer’s Disease Neuroimaging Initiative; Radiology and Imaging Sciences, School of MedicineIntroduction: It is unclear how rates of white matter microstructural decline differ between normal aging and abnormal aging. Methods: Diffusion MRI data from several well-established longitudinal cohorts of aging [Alzheimer's Neuroimaging Initiative (ADNI), Baltimore Longitudinal Study of Aging (BLSA), Vanderbilt Memory & Aging Project (VMAP)] was free-water corrected and harmonized. This dataset included 1,723 participants (age at baseline: 72.8±8.87 years, 49.5% male) and 4,605 imaging sessions (follow-up time: 2.97±2.09 years, follow-up range: 1-13 years, mean number of visits: 4.42±1.98). Differences in white matter microstructural decline in normal and abnormal agers was assessed. Results: While we found global decline in white matter in normal/abnormal aging, we found that several white matter tracts (e.g., cingulum bundle) were vulnerable to abnormal aging. Conclusions: There is a prevalent role of white matter microstructural decline in aging, and future large-scale studies in this area may further refine our understanding of the underlying neurodegenerative processes. Highlights: Longitudinal data was free-water corrected and harmonizedGlobal effects of white matter decline were seen in normal and abnormal agingThe free-water metric was most vulnerable to abnormal agingCingulum free-water was the most vulnerable to abnormal aging.Item Longitudinal change in memory performance as a strong endophenotype for Alzheimer's disease(Wiley, 2024) Archer, Derek B.; Eissman, Jaclyn M.; Mukherjee, Shubhabrata; Lee, Michael L.; Choi, Seo-Eun; Scollard, Phoebe; Trittschuh, Emily H.; Mez, Jesse B.; Bush, William S.; Kunkle, Brian W.; Naj, Adam C.; Gifford, Katherine A.; Alzheimer's Disease Neuroimaging Initiative (ADNI); Alzheimer's Disease Genetics Consortium (ADGC); Alzheimer's Disease Sequencing Project (ADSP); Cuccaro, Michael L.; Pericak-Vance, Margaret A.; Farrer, Lindsay A.; Wang, Li-San; Schellenberg, Gerard D.; Mayeux, Richard P.; Haines, Jonathan L.; Jefferson, Angela L.; Kukull, Walter A.; Keene, C. Dirk; Saykin, Andrew J.; Thompson, Paul M.; Martin, Eden R.; Bennett, David A.; Barnes, Lisa L.; Schneider, Julie A.; Crane, Paul K.; Dumitrescu, Logan; Hohman, Timothy J.; Radiology and Imaging Sciences, School of MedicineIntroduction: Although large-scale genome-wide association studies (GWAS) have been conducted on AD, few have been conducted on continuous measures of memory performance and memory decline. Methods: We conducted a cross-ancestry GWAS on memory performance (in 27,633 participants) and memory decline (in 22,365 participants; 129,201 observations) by leveraging harmonized cognitive data from four aging cohorts. Results: We found high heritability for two ancestry backgrounds. Further, we found a novel ancestry locus for memory decline on chromosome 4 (rs6848524) and three loci in the non-Hispanic Black ancestry group for memory performance on chromosomes 2 (rs111471504), 7 (rs4142249), and 15 (rs74381744). In our gene-level analysis, we found novel genes for memory decline on chromosomes 1 (SLC25A44), 11 (BSX), and 15 (DPP8). Memory performance and memory decline shared genetic architecture with AD-related traits, neuropsychiatric traits, and autoimmune traits. Discussion: We discovered several novel loci, genes, and genetic correlations associated with late-life memory performance and decline. Highlights: Late-life memory has high heritability that is similar across ancestries. We discovered four novel variants associated with late-life memory. We identified four novel genes associated with late-life memory. Late-life memory shares genetic architecture with psychiatric/autoimmune traits.Item Novel rare variant associations with late‐life cognitive performance(Wiley, 2025-01-09) Regelson, Alexandra N.; Archer, Derek B.; Durant, Alaina; Mukherjee, Shubhabrata; Lee, Michael L.; Choi, Seo-Eun; Scollard, Phoebe; Trittschuh, Emily H.; Mez, Jesse; Bush, William S.; Kuzma, Amanda B.; Cuccaro, Michael L.; Cruchaga, Carlos; Farrer, Lindsay A.; Wang, Li-San; Schellenberg, Gerard D.; Mayeux, Richard; Kukull, Walter A.; Keene, C. Dirk; Saykin, Andrew J.; Johnson, Sterling C.; Engelman, Corinne D.; Bennett, David A.; Barnes, Lisa L.; Larson, Eric B.; Nho, Kwangsik; Goate, Alison M.; Renton, Alan E.; Marcora, Edoardo; Fulton-Howard, Brian; Patel, Tulsi; Risacher, Shannon L.; DeStefano, Anita L.; Schneider, Julie A.; Habes, Mohamad; Seshadri, Sudha; Satizabal, Claudia L.; Maillard, Pauline; Toga, Arthur W.; Crawford, Karen; Tosun, Duygu; Vance, Jeffery M.; Mormino, Elizabeth; DeCarli, Charles S.; Montine, Thomas J.; Beecham, Gary; Biber, Sarah A.; De Jager, Philip L.; Vardarajan, Badri N.; Lee, Annie J.; Brickman, Adam M.; Reitz, Christiane; Manly, Jennifer J.; Lu, Qiongshi; Rentería, Miguel Arce; Deming, Yuetiva; Pericak-Vance, Margaret A.; Haines, Jonathan L.; Crane, Paul K.; Hohman, Timothy J.; Dumitrescu, Logan C.; Medical and Molecular Genetics, School of MedicineBackground: Despite evidence that Alzheimer’s disease (AD) is highly heritable, there remains substantial “missing” heritability, likely due in part to the effect of rare variants and to the past reliance on case‐control analysis. Here, we leverage powerful endophenotypes of AD (cognitive performance across multiple cognitive domains) in a rare variant analysis to identify novel genetic drivers of cognition in aging and disease. Method: We leveraged 8 cohorts of cognitive aging with whole genome sequencing data from the AD Sequencing Project to conduct rare variant analyses of multiple domains of cognition (N = 9,317; mean age = 73; 56% female; 52% cognitively unimpaired). Harmonized scores for memory, executive function, and language were derived using confirmatory factor analysis models. Participants genetically similar to the 1000Genomes EUR reference panel were included in analysis. Variants included in the analysis had a minor allele frequency < 0.01, a minor allele count of ≥ 10, and were annotated as a high or moderate impact SNP using VEP. Associations of baseline scores in each cognitive domain were performed using SKAT‐O, including 92,905 rare variants among 16,243 genes. All tests were adjusted for sex, baseline age, sequencing center and platform, and genetic principal components. Correction for multiple comparisons was completed using the Benjamini‐Hochberg false discovery rate (FDR) procedure. Result: APOE was associated with baseline memory, language, and executive function, though only memory survived multiple‐test correction (p.FDR = 0.001). Outside of APOE, ITPKB was associated with baseline executive function (p.FDR = 0.048). AKTIP, SHCBP1L, and CCNF showed nominal associations with multiple domains of cognition that did not survive correction for multiple comparisons (p.FDRs<0.07). Conclusion: These results highlight novel rare variants associated with cognition. IPTKB is an AGORA nominated gene target for potential AD treatment. It is important in the regulation of immune cells and displays higher expression in the cortex of AD patients compared to controls. CCNF and AKTIP are brain eQTLs and have differential RNA expression in AD brains. Previously, variants in AKTIP have been associated with educational attainment, intelligence, and memory, while variants in CCNF have been associated with neuritic plaques and neurofibrillary tangles. Future analyses will incorporate longitudinal cognition and expand into additional populations.Item Sex and APOE ε4 allele differences in longitudinal white matter microstructure in multiple cohorts of aging and Alzheimer's disease(Wiley, 2025) Peterson, Amalia; Sathe, Aditi; Zaras, Dimitrios; Yang, Yisu; Durant, Alaina; Deters, Kacie D.; Shashikumar, Niranjana; Pechman, Kimberly R.; Kim, Michael E.; Gao, Chenyu; Khairi, Nazirah Mohd; Li, Zhiyuan; Yao, Tianyuan; Huo, Yuankai; Dumitrescu, Logan; Gifford, Katherine A.; Wilson, Jo Ellen; Cambronero, Francis E.; Risacher, Shannon L.; Beason-Held, Lori L.; An, Yang; Arfanakis, Konstantinos; Erus, Guray; Davatzikos, Christos; Tosun, Duygu; Toga, Arthur W.; Thompson, Paul M.; Mormino, Elizabeth C.; Habes, Mohamad; Wang, Di; Zhang, Panpan; Schilling, Kurt; Alzheimer's Disease Neuroimaging Initiative (ADNI); BIOCARD Study Team; Alzheimer's Disease Sequencing Project (ADSP); Albert, Marilyn; Kukull, Walter; Biber, Sarah A.; Landman, Bennett A.; Johnson, Sterling C.; Schneider, Julie; Barnes, Lisa L.; Bennett, David A.; Jefferson, Angela L.; Resnick, Susan M.; Saykin, Andrew J.; Hohman, Timothy J.; Archer, Derek B.; Radiology and Imaging Sciences, School of MedicineIntroduction: The effects of sex and apolipoprotein E (APOE)-Alzheimer's disease (AD) risk factors-on white matter microstructure are not well characterized. Methods: Diffusion magnetic resonance imaging data from nine well-established longitudinal cohorts of aging were free water (FW)-corrected and harmonized. This dataset included 4741 participants (age = 73.06 ± 9.75) with 9671 imaging sessions over time. FW and FW-corrected fractional anisotropy (FAFWcorr) were used to assess differences in white matter microstructure by sex and APOE ε4 carrier status. Results: Sex differences in FAFWcorr in projection tracts and APOE ε4 differences in FW limbic and occipital transcallosal tracts were most pronounced. Discussion: There are prominent differences in white matter microstructure by sex and APOE ε4 carrier status. This work adds to our understanding of disparities in AD. Additional work to understand the etiology of these differences is warranted. Highlights: Sex and apolipoprotein E (APOE) ε4 carrier status relate to white matter microstructural integrity. Females generally have lower free water-corrected fractional anisotropy compared to males. APOE ε4 carriers tended to have higher free water than non-carriers.Item Sex, racial, and APOE-ε4 allele differences in longitudinal white matter microstructure in multiple cohorts of aging and Alzheimer’s disease(bioRxiv, 2024-06-12) Peterson, Amalia; Sathe, Aditi; Zaras, Dimitrios; Yang, Yisu; Durant, Alaina; Deters, Kacie D.; Shashikumar, Niranjana; Pechman, Kimberly R.; Kim, Michael E.; Gao, Chenyu; Khairi, Nazirah Mohd; Li, Zhiyuan; Yao, Tianyuan; Huo, Yuankai; Dumitrescu, Logan; Gifford, Katherine A.; Wilson, Jo Ellen; Cambronero, Francis; Risacher, Shannon L.; Beason-Held, Lori L.; An, Yang; Arfanakis, Konstantinos; Erus, Guray; Davatzikos, Christos; Tosun, Duygu; Toga, Arthur W.; Thompson, Paul M.; Mormino, Elizabeth C.; Zhang, Panpan; Schilling, Kurt; Alzheimer’s Disease Neuroimaging Initiative (ADNI); BIOCARD Study Team; Alzheimer’s Disease Sequencing Project (ADSP); Albert, Marilyn; Kukull, Walter; Biber, Sarah A.; Landman, Bennett A.; Johnson, Sterling C.; Schneider, Julie; Barnes, Lisa L.; Bennett, David A.; Jefferson, Angela L.; Resnick, Susan M.; Saykin, Andrew J.; Hohman, Timothy J.; Archer, Derek B.; Radiology and Imaging Sciences, School of MedicineIntroduction: The effects of sex, race, and Apolipoprotein E (APOE) - Alzheimer's disease (AD) risk factors - on white matter integrity are not well characterized. Methods: Diffusion MRI data from nine well-established longitudinal cohorts of aging were free-water (FW)-corrected and harmonized. This dataset included 4,702 participants (age=73.06 ± 9.75) with 9,671 imaging sessions over time. FW and FW-corrected fractional anisotropy (FAFWcorr) were used to assess differences in white matter microstructure by sex, race, and APOE-ε4 carrier status. Results: Sex differences in FAFWcorr in association and projection tracts, racial differences in FAFWcorr in projection tracts, and APOE-ε4 differences in FW limbic and occipital transcallosal tracts were most pronounced. Discussion: There are prominent differences in white matter microstructure by sex, race, and APOE-ε4 carrier status. This work adds to our understanding of disparities in AD. Additional work to understand the etiology of these differences is warranted.Item Sex, racial/ethnic, and APOE‐ε4 allele differences in longitudinal white matter microstructure in multiple cohorts of aging(Wiley, 2025-01-09) Peterson, Amalia Jo; Sathe, Aditi; Yang, Yisu; Durant, Alaina; Shashikumar, Niranjana; Pechman, Kimberly R.; Dumitrescu, Logan C.; Gifford, Katherine A.; Risacher, Shannon L.; Beason-Held, Lori L.; An, Yang; Schilling, Kurt; Landman, Bennett A.; Schneider, Julie A.; Barnes, Lisa L.; Bennett, David A.; Jefferson, Angela L.; Resnick, Susan M.; Saykin, Andrew J.; Hohman, Timothy J.; Archer, Derek B.; Alzheimer’s Disease Neuroimaging Initiative (ADNI); Radiology and Imaging Sciences, School of MedicineBackground: There is growing recognition that white matter microstructural integrity is affected in Alzheimer’s disease. The goal of this study was to characterize sex, racial/ethnic, and apolipoprotein (APOE)‐ε4 allele differences in white matter integrity. Methods: This study included participants from ADNI, BLSA, ROS/MAP/MARS, and VMAP, all longitudinal cohorts of aging. This combined dataset included 6,837 imaging sessions from 2,619 participants age 50+ with diffusion MRI (dMRI) and demographic and clinical data (60% female, 31.4% APOE‐ε4 carriers, 78.9% White). dMRI was preprocessed using the PreQual pipeline. Free‐water (FW) correction was used to generate FW and FW‐corrected intracellular metrics including fractional anisotropy (FAFWcorr), mean diffusivity (MDFWcorr), axial diffusivity (AxDFWcorr), and radial diffusivity (RDFWcorr). Conventional and FW‐corrected metrics were harmonized using the Longitudinal ComBat package. Linear mixed‐effects models related sex, race/ethnicity, and APOE‐ε4 allele status to longitudinal diffusion metrics in 48 white matter tracts, adjusting for age at baseline, sex, education, race/ethnicity, APOE‐ε4 carrier status, cognitive status at baseline, and converter status. All models were corrected for multiple comparisons using the FDR approach. Result: Sex differences in white matter were most notable in projection tracts (Figure 1A) and were primarily in FW‐corrected metrics. Females had lower FAFWcorr and higher RDFWcorr, indicative of worse microstructure, but lower AxDFWcorr. This sex difference was most pronounced for FAFWcorr in the ventral premotor projection tract (p=1.53x10‐62). There were global differences in white matter integrity by race/ethnicity (Figure 1B). Non‐Hispanic White participants tended to have higher conventional FA, FAFWcorr and AxDFWcorr and lower RDFWcorr. There was no association between APOE‐ε4 status and white matter integrity and no significant sex x race/ethnicity, sex x APOE‐ε4, or race/ethnicity x APOE‐ε4 interactions for conventional or FW‐corrected metrics when corrected for multiple comparisons. Conclusion: There were striking sex and racial/ethnic (but not APOE‐ε4) differences in white matter tract integrity in a large cohort of aging adults. Female participants tended to have measures reflective of worse white matter integrity, and non‐Hispanic White participants tended to have measures reflective of greater integrity. Additional research exploring the etiology of these differences will be important to better understand disparities in Alzheimer’s disease.Item Sex-specific genetic architecture of late-life memory performance(Wiley, 2024) Eissman, Jaclyn M.; Archer, Derek B.; Mukherjee, Shubhabrata; Lee, Michael L.; Choi, Seo-Eun; Scollard, Phoebe; Trittschuh, Emily H.; Mez, Jesse B.; Bush, William S.; Kunkle, Brian W.; Naj, Adam C.; Gifford, Katherine A.; Alzheimer's Disease Neuroimaging Initiative (ADNI); Alzheimer's Disease Genetics Consortium (ADGC); The Alzheimer's Disease Sequencing Project (ADSP); Cuccaro, Michael L.; Cruchaga, Carlos; Pericak-Vance, Margaret A.; Farrer, Lindsay A.; Wang, Li-San; Schellenberg, Gerard D.; Mayeux, Richard P.; Haines, Jonathan L.; Jefferson, Angela L.; Kukull, Walter A.; Keene, C. Dirk; Saykin, Andrew J.; Thompson, Paul M.; Martin, Eden R.; Bennett, David A.; Barnes, Lisa L.; Schneider, Julie A.; Crane, Paul K.; Hohman, Timothy J.; Dumitrescu, Logan; Radiology and Imaging Sciences, School of MedicineBackground: Women demonstrate a memory advantage when cognitively healthy yet lose this advantage to men in Alzheimer's disease. However, the genetic underpinnings of this sex difference in memory performance remain unclear. Methods: We conducted the largest sex-aware genetic study on late-life memory to date (Nmales = 11,942; Nfemales = 15,641). Leveraging harmonized memory composite scores from four cohorts of cognitive aging and AD, we performed sex-stratified and sex-interaction genome-wide association studies in 24,216 non-Hispanic White and 3367 non-Hispanic Black participants. Results: We identified three sex-specific loci (rs67099044-CBLN2, rs719070-SCHIP1/IQCJ-SCHIP), including an X-chromosome locus (rs5935633-EGL6/TCEANC/OFD1), that associated with memory. Additionally, we identified heparan sulfate signaling as a sex-specific pathway and found sex-specific genetic correlations between memory and cardiovascular, immune, and education traits. Discussion: This study showed memory is highly and comparably heritable across sexes, as well as highlighted novel sex-specific genes, pathways, and genetic correlations that related to late-life memory. Highlights: Demonstrated the heritable component of late-life memory is similar across sexes. Identified two genetic loci with a sex-interaction with baseline memory. Identified an X-chromosome locus associated with memory decline in females. Highlighted sex-specific candidate genes and pathways associated with memory. Revealed sex-specific shared genetic architecture between memory and complex traits.Item Uncovering the role of white matter microstructure in longitudinal memory and executive function decline: insights from a multi‐site study of 2,220 participants across 4,918 paired imaging‐cognition sessions(Wiley, 2025-01-09) Archer, Derek B.; Peter, Chris; Sathe, Aditi; Yang, Yisu; Durant, Alaina; Shashikumar, Niranjana; Pechman, Kimberly R.; Dumitrescu, Logan C.; Gifford, Katherine A.; Mukherjee, Shubhabrata; Klinedinst, Brandon S.; Lee, Michael L.; Choi, Seo-Eun; Scollard, Phoebe; Trittschuh, Emily H.; Risacher, Shannon L.; Beason-Held, Lori L.; An, Yang; Schilling, Kurt; Landman, Bennett A.; Schneider, Julie A.; Barnes, Lisa L.; Bennett, David A.; Crane, Paul K.; Kukull, Walter A.; Johnson, Sterling C.; Albert, Marilyn S.; Jefferson, Angela L.; Resnick, Susan M.; Saykin, Andrew J.; Hohman, Timothy J.; Alzheimer's Disease Neuroimaging Initiative (ADNI); Radiology and Imaging Sciences, School of MedicineBackground: Recent research emphasizes the significance of white matter tracts and the free‐water (FW) component in understanding cognitive decline. The goal of this study is to conduct a large‐scale assessment on the role of white matter microstructure on longitudinal cognitive decline. Method: This study used a cohort collated from seven longitudinal cohorts of aging (ADNI, BIOCARD, BLSA, NACC, ROS/MAP/MARS, VMAP, and WRAP). In total, this dataset included 2,220 participants aged 50+ who had both diffusion MRI and harmonized composites of memory performance and executive function. This dataset included a total of 4,918 imaging sessions with corresponding cognitive data (mean number of visits per participant: 1.69 ± 1.67, interval range: 1‐10 years). Diffusion MRI was preprocessed using the PreQual pipeline and FW correction was used to create FW and FW‐corrected intracellular metrics. Conventional and FW‐corrected measures were harmonized using the Longitudinal ComBat package. Linear mixed effects regression was used for longitudinal analysis, in which we covaried for age, age squared, education, sex, race/ethnicity, diagnosis at baseline, APOE‐ε4 status, and APOE‐ε2 status. All models were corrected for multiple comparisons using the FDR approach. Result: For longitudinal memory performance, we found global associations with conventional diffusion MRI metrics, in which abnormalities were associated with lower memory performance. Following FW correction, we found that the FW metric itself was strongly associated with memory performance, in which higher FW was associated with lower memory performance and exacerbated decline. Interestingly, following FW‐correction the intracellular contributions were largely mitigated. As illustrated in Figure 1A, the most significant effects were found in the limbic tracts, with the most significant associations found for cingulum bundle FW (p=5.80x10‐45). Figure 1B illustrates the association between cingulum FW and longitudinal memory performance. Findings for longitudinal executive function performance are shown in Figure 2. Conclusion: To date, this is the largest study combining FW‐corrected diffusion MRI data and harmonized cognitive composites to understand cognitive trajectories in aging. Future studies evaluating how white matter microstructure may be incorporated into models of AD may further our knowledge into the neurodegenerative cascade of AD.