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npj Aging

Springer Science and Business Media LLC

Preprints posted in the last 7 days, ranked by how well they match npj Aging's content profile, based on 15 papers previously published here. The average preprint has a 0.04% match score for this journal, so anything above that is already an above-average fit.

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Transcriptomic Profiling in Skeletal Muscle Identifies Associations With Knee Osteoarthritis: the Study of Muscle, Mobility and Aging (SOMMA)

Evans, D. S.; Mansfield, T. A.; Many, G. M.; Sagendorf, T. J.; Farsijani, S.; Goodpaster, B. H.; Sparks, L. M.; Lane, N. E.

2026-04-16 genetic and genomic medicine 10.64898/2026.04.14.26350906 medRxiv
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Objectives. The association between skeletal muscle gene expression and knee osteoarthritis (OA) was examined among older adult participants of the Study of Muscle, Mobility and Aging (SOMMA). Methods. Inclusion criteria included knee radiographs and bulk RNA sequencing (RNAseq) in vastus lateralis muscle, resulting in 523 participants (56% female). Radiographic knee OA was determined by Kellgren-Lawrence (KL) grades. Differential gene expression was analyzed using a control group (KL [≤] 1, n = 326) and two nested case groups: (a) KL [≥] 2 (n = 197), (b) KL [≥] 3 (n = 112). Results. Compared with controls, there were 27 and 41 genes associated (FDR [≤] 0.05) with KL [≥] 2 and KL [≥] 3, respectively, and 16 genes significantly associated in both contrasts. For 15 of the 16 genes, the association magnitude was larger with more severe OA (KL [≥] 3). Genes associated in both contrasts included brain-derived neurotrophic factor (BDNF) and interferon regulatory factor-2 (IRF2). Gene sets enriched in KL [≥] 2 and KL [≥] 3 contrasts included DNA repair and branched chain amino acid (BCAA) catabolism. Conclusions. Our results in older adult SOMMA participants indicate that knee OA is associated with genes and pathways expressed in skeletal muscle that are involved in pain sensitization, BCAA catabolism, muscle function preservation, calcium transport and storage, inflammation, and extracellular matrix remodeling. Additional longitudinal studies will be needed to determine how these genes could affect the progression of knee OA.

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Trajectories of physical activity components among community-dwelling older adults.

Hoogerheide, B.; Maas, E.; Visser, M.; Hoekstra, T.; Schaap, L.

2026-04-11 rehabilitation medicine and physical therapy 10.64898/2026.04.10.26350593 medRxiv
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Background/Objective: Common measures of physical activity (PA) based on duration and intensity do not fully capture its complexity. Adding additional PA components of muscle strength, mechanical strain, and turning actions, can provide a more complete view of activity behavior. Furthermore, PA behaviors differ between men and women. Therefore, the goal of this study is to identify and cluster similar long-term PA patterns over time for each PA component, examined separately for men and women. Methods: We used data from 4963 participants (52% women; mean age 66 years, SD = 8.6) of the Longitudinal Aging Study Amsterdam (1992 to 2019). PA component scores were assigned to self-reported activities, and Sequence Analysis with Optimal Matching was used to identify and cluster similar activity patterns over a period of 10 years, separately for each component and stratified by sex. Results: PA components varied by sex and displayed a unique mix of trajectories, including predominately low, medium, or high activity, increasing or decreasing patterns, and trajectories characterized by early or late mortality. Importantly, trajectories remained independent, indicating that changes in one PA component were not linked to changes in others. Conclusion: Older men and women follow distinct and independent long term PA trajectories across components, underscoring that PA behaviour cannot be described by a single dimension. Significance/Implications: The observed independence and heterogeneity of trajectories suggest that muscle strength, mechanical strain, and turning actions capture meaningful and distinct aspects of PA that are not reflected by traditional measures alone. Future PA-strategies could incorporate these dimensions and acknowledge sex-specific patterns to better reflect natural movement. The independence of components suggests that future interventions should target multiple dimensions, as changes in one component may not translate to others. Such an approach may support more tailored and sustainable PA interventions in later life.

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A Multi-Cohort Study of Immunoglobulin G Glycans in Newly Diagnosed Inflammatory Bowel Disease Patients Reveals Accelerated Biological Aging

Flevaris, K.; Trbojevic-Akmacic, I.; Goh, D.; Lalli, J. S.; Vuckovic, F.; Capin Vilaj, M.; Stambuk, J.; Kristic, J.; Mijakovac, A.; Ventham, N.; Kalla, R.; Latiano, A.; Manetti, N.; Li, D.; McGovern, D. P. B.; Kennedy, N. A.; Annese, V.; Lauc, G.; Satsangi, J.; Kontoravdi, C.

2026-04-11 gastroenterology 10.64898/2026.04.10.26349930 medRxiv
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Background and Aims: Alterations in immunoglobulin G (IgG) N-glycosylation are implicated in inflammatory bowel disease (IBD); however, the robustness of IgG glycan signatures across IBD cohorts with diverse demographics and geographic origins remains underexplored. We aimed to determine whether compositional data analysis (CoDA) and machine learning (ML) can identify IBD-related IgG N-glycan signatures and whether these signatures capture disease-associated acceleration of biological aging. Methods: We analyzed the IgG glycome profiles of 1,367 plasma samples collected from healthy controls (HC), symptomatic controls (SC), and people with newly diagnosed Crohn's (CD), and ulcerative colitis (UC) across four cohorts (UK, Italy, United States, and Netherlands). IgG glycosylation was analyzed by ultra-high-performance liquid chromatography, yielding 24 total-area-normalized glycan peaks (GPs). Analyses were performed using cross-sectional data obtained at baseline. CoDA-powered association analyses were used to identify disease-related effects on GPs while controlling for demographic covariates. ML models were trained and evaluated to assess generalizability to unseen cohorts and demographic subgroups, with a focus on discrimination and reliability. Results: Across all cohorts, people with IBD demonstrated accelerated biological aging as quantified by the GlycanAge index. This was accompanied by consistent reductions in IgG galactosylation, with effects partially modulated by age. Classification models trained on glycomics and demographics achieved robust discrimination (AUROC~0.80) between non-IBD (HC+SC) and IBD across cohorts. Conclusion: These findings reveal accelerated biological aging in people with IBD and support the translational potential of IgG glycans as biomarkers and a novel route toward clinically interpretable personalized risk estimates.

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A multidomain intrinsic capacity score tracks longitudinal health trajectories in the UK Biobank

Zhai, T.; Babu, M.; Fuentealba, M.; Al Dajani, S.; Gladyshev, V. N.; Furman, D.; Snyder, M.

2026-04-13 epidemiology 10.64898/2026.04.10.26350621 medRxiv
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Quantitative measures for tracking functional health have generally been lacking. Intrinsic capacity (IC) has been proposed as an appropriate measure, but its metrics have been derived in small datasets and sparse longitudinal data. Using harmonized measures of cognition, locomotion, sensory function, vitality, and psychological well-being from 501,615 UK Biobank participants and followed for a median of 15.5 years, we derived domain-specific and composite IC scores. We examined associations with incident disease, cause-specific mortality, multimorbidity, lifestyle and socioeconomic factors, and multi-omic profiles from Olink proteomics, NMR metabolomics, clinical biochemistry, and blood-cell traits. We found that composite IC declined non-linearly with age, and within-person decline was steeper than the cross-sectional age measures. Participants with greater baseline morbidity, those who subsequently developed incident disease, and those who died earlier in follow-up showed lower IC trajectories across adulthood. The IC domains were only modestly correlated with one another, supporting multidimensionality, yet higher overall IC was associated with lower risk of most diseases examined. The dominant IC domain varied by endpoint, with cognition informative for dementia, sensory function for hearing loss, psychological capacity for depression, locomotion for osteoarthritis, and vitality for cardiometabolic outcomes. IC was also associated cross-sectionally with physical activity, insomnia, smoking, medication burden, and socioeconomic disadvantage. More proteins were found predictive for vitality, and enrichment converged on immune/inflammatory and metabolic pathways. Blood-based surrogates recapitulated part of the phenotypic signal, particularly for vitality. Overall, this IC framework captures longitudinal health trajectories and broad disease vulnerability in a large middle- to older-aged cohort and supports IC as a clinically meaningful, multidomain phenotype of aging and identifies blood-based correlates that may facilitate at-scale future monitoring of aging-related function declines.

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Characteristic resting state facial expressions in older adults with mild cognitive impairment level

Miyayama, M.; Sekiguchi, T.; Sugimoto, H.; Kawagoe, T.; Tripanpitak, K.; Wolf, A.; Kumagai, K.; Fukumori, K.; Miura, K. W.; Okada, S.; Ishimaru, K.; Otake-Matsuura, M.

2026-04-11 geriatric medicine 10.64898/2026.04.10.26350581 medRxiv
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Background: For early detection of Alzheimer's disease, it is essential to identify individuals showing cognitive performance consistent with the mild cognitive impairment (MCI) range during preliminary screening, ideally using methods that extend beyond conventional cognitive assessments. Non-invasive, easily accessible screening tools applicable in daily life are increasingly needed. Facial expressions, particularly during rest, may offer promising biomarkers for MCI level detection. This study aimed to identify specific facial features associated with MCI level during rest to inform development of facial expression-based screening tools. Methods: Participants were classified into an MCI level group and a healthy control (HC) group based on the Montreal Cognitive Assessment (MoCA) scores. Facial Action Units (AUs) were extracted from video recordings of resting-state facial expressions in 31 individuals with MCI level and 14 HC. Two statistical models were employed: a multilevel zero-inflated beta regression model for intensity of 17 AUs and a multilevel logistic regression model for presence or absence of 18 AUs. Results: In the zero-inflated beta regression, the AU relates to upper lip raiser showed a significant group effect (MCI level vs. HC; p <0.001), remaining significant after multiple comparison correction. The logistic regression revealed significant group differences for the AUs related to lip tightener (p <0.001) and lip suck (p <0.001), both remained significant after multiple comparison correction. Conclusions: Distinctive facial action patterns during rest were observed in individuals with MCI level. These findings highlight the potential of resting-state facial expressions as a basis for novel, unobtrusive screening tools for early MCI level detection.

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Pre-Dementia Indicators and Multidomain Vulnerabilities: Insights from AD8 Screening in Older Chinese Speaking Adults

You, W.; Koo, F. K.; Cheng, Y.; Huang, J.; Huang, H.; Li, M.; Sevastidis, J.; Chang, H.-C.

2026-04-13 geriatric medicine 10.64898/2026.04.08.26350424 medRxiv
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BackgroundEarly recognition of dementia-related changes is critical for timely intervention. The AD8 Dementia Screening Interview (AD8) detects subtle cognitive and functional changes, yet its broader associations with health and wellbeing among Chinese-speaking older adults remain underexplored. MethodsA cross-sectional study was conducted with 144 community-dwelling Chinese older adults (mean age 73.1 years; 81.3% female). Participants completed sociodemographic, health, functional, and psychosocial measures, including the AD8 and the Geriatric Depression Scale (GDS-15). Exploratory Factor Analysis (EFA) assessed the dimensionality of the AD8, and binary logistic regression examined associations between AD8 items and demographic, health, functional, and psychosocial outcomes. ResultsChronic disease was prevalent (68.1 percent), and 13.2 percent reported a mental health disorder. EFA identified three domains: memory impairment, executive and interest decline, and functional recall difficulties, explaining 61.7 percent of the variance. Logistic regression showed predictive roles for judgment problems (AD8_1), repetition (AD8_3), financial difficulties (AD8_6), tool-use difficulties (AD8_4), and daily memory problems (AD8_8). Financial and executive difficulties were associated with age and mobility challenges, while repetition predicted psychological disorders and hopelessness. Judgment problems were linked to lower life satisfaction and happiness but greater helplessness. Worthlessness was predicted by financial, tool-use, and memory difficulties, whereas intact temporal recall (AD8_5) was protective. Several outcomes including boredom, low energy, and staying home were not significant. ConclusionDistinct AD8 items predicted vulnerabilities across physical, psychological, and social domains. Findings highlight the multidimensional value of the AD8 as a culturally relevant screening and risk stratification tool for community-based assessments of Chinese older adults. Summary Statement Implications for PracticeO_ST_ABSWhat does this research add to existing knowledge in gerontology?C_ST_ABSThis study shows that specific AD8 items identify early multidimensional vulnerability among community-dwelling Chinese-speaking older adults. Difficulties with judgment, repetition, financial management, tool use, and daily memory were associated with functional limitations and psychosocial distress, extending the AD8 beyond dementia screening alone. The identification of three AD8 domains supports a broader understanding of early cognitive change as involving cognitive, functional, and emotional processes. The findings contribute culturally specific evidence from an under-researched population in gerontological research. What are the implications of this new knowledge for nursing care with older people?For nursing practice, the AD8 provides a brief, feasible tool to support holistic assessment in community and aged care settings. Key AD8 indicators can guide nurses in identifying older people at risk of functional decline and emotional vulnerability, enabling earlier, person-centred interventions. The findings highlight the importance of culturally and linguistically appropriate assessment when caring for diverse ageing populations. How could the findings be used to influence policy or practice or research or education?The results support integrating brief cognitive screening into routine nursing assessments and community-based aged care services to promote early identification and ageing in place. Nursing education should emphasise interpreting cognitive screening within psychosocial and cultural contexts. Longitudinal research is needed to assess intervention effectiveness. Key Points[tpltrtarr] Early cognitive changes matter for older Chinese-speaking adults, because difficulties with judgment, repetition, financial management, and tool use (AD8 domains) were consistently linked to poorer functional and psychosocial outcomes. [tpltrtarr]Beyond dementia screening, the AD8 proved useful for detecting vulnerabilities in wellbeing and daily functioning, extending its role beyond diagnostic sensitivity. [tpltrtarr]A cultural focus is vital, as this study is among the first to examine AD8 associations in older Chinese-speaking adults, underscoring the need for culturally tailored screening. [tpltrtarr]The psychosocial impact of cognitive changes was evident, with strong associations to helplessness, worthlessness, and reduced life satisfaction, reinforcing the overlap between cognitive and emotional health. [tpltrtarr]In practice, integrating AD8 screening into community and primary care could help identify at-risk individuals early and support targeted interventions in culturally and linguistically diverse populations.

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Effectiveness of a Socially Implemented Cognitive Decline Prevention Program: A Retrospective Observational Study

Kouzuki, M.; Fujita, K.

2026-04-11 geriatric medicine 10.64898/2026.04.08.26350304 medRxiv
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Background and ObjectivesMultifactorial interventions have been reported to be effective in improving cognitive function; however, their long-term effectiveness in community settings remains to be sufficiently examined. This study aimed to investigate the effects of a socially implemented multifactorial intervention program on dementia onset, long-term care insurance certification, and post-intervention cognitive and physical functions. MethodsThis retrospective observational study collected data from three municipalities. The study population comprised individuals suspected of having mild cognitive decline based on cognitive function screening tests conducted by March 31, 2024, and who had been invited to participate in a dementia prevention class, but had not applied for long-term care insurance at the time of the invitation. Participants were classified into class participation and non-participation groups for analysis. Most participants attended the class only once (intervention duration: 4 or 6 months). ResultsData from 104, 218, and 256 individuals were collected from the three municipalities, respectively. No significant association was found between class participation and suppression of dementia onset or long-term care insurance certification in any of the municipalities. Regarding pre-post comparisons among class participants, significant improvements in cognitive function and some physical functions were observed in all the three municipalities. ConclusionsThe multifactorial interventions implemented in community settings showed no effect on dementia onset or health outcomes. However, class participation was associated with improvements in cognitive function and some physical functions. These findings suggest that implementing programs based on evidence can achieve effects similar to those observed in studies conducted under ideal conditions.

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Dissecting PON1 Genotype Combinations Modulating Paraoxonase Activity and Risk of Dysglycemia and Liver Fibrosis

Herrera, L.; Meneses, M. J.; Ribeiro, R. T.; Gardete-Correia, L.; Raposo, J. F.; Boavida, J. M.; Penha-Goncalves, C.; Macedo, M. P.

2026-04-13 endocrinology 10.64898/2026.04.09.26350501 medRxiv
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Background & AimsMetabolic disorders such as dyslipidemia, metabolic dysfunction-associated steatotic liver disease (MASLD), and diabetes are promoted by chronic pro-inflammatory and pro-oxidative states. Paraoxonase 1 (PON1), a liver-derived HDL-associated enzyme, plays an important antioxidant role by hydrolyzing oxidized lipids and protecting against oxidative stress- induced damage. Genetic variation in PON1, particularly in promoter and coding regions, modulates enzyme expression and activity, thereby influencing susceptibility to metabolic and cardiovascular diseases. This study investigated the genetic determinants of serum paraoxonase (PONase) activity and their relationship with dysmetabolic phenotypes. MethodsA genome-wide association study was conducted in 922 Portuguese individuals from the PREVADIAB2 cohort. Genetic variants and haplotypes related to PONase activity were analyzed, and associations with dysglycemia and liver fibrosis were evaluated in individuals aged over 55 years. ResultsWe identified two key PON1 variants as determinants of PONase activity: rs2057681 (in strong linkage disequilibrium with the non-synonymous Q192R variant) and rs854572 (located in the promoter region). Analysis of rs854572-rs2057681 haplotypes revealed that specific combinations differentially modulate PONase activity and confer risk or protection for dysglycemia and liver fibrosis, depending on the rs2057681 genotype context. Notably, although PONase activity was strongly associated with PON1 variants, it did not directly correlate with dysmetabolic phenotypes, suggesting that genetic context and haplotype structure, rather than enzyme activity alone, shape disease susceptibility. ConclusionsThese findings highlight the complex genetic architecture of PON1 and its role in metabolic disease risk, supporting the use of PON1 genetic information to uncover predisposition to dysmetabolic conditions. Our results provide insights into the interplay between PON1 genetics, enzyme function, and dysmetabolism, with implications for risk stratification in metabolic liver disease. Lay SummaryPON1 is a liver-derived gene that encodes an enzyme involved in protection against oxidative stress, a key contributor to metabolic liver disease and diabetes. In this study, we found that specific combinations of PON1 genetic variants are associated with abnormalities in blood glucose regulation and with markers of liver fibrosis. These associations were dependent on genetic configuration rather than enzyme activity alone, suggesting that PON1 genetic information may help identify individuals at higher risk of metabolic liver disease.

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Sex Differences in Comparative Effectiveness and Safety of Second-line Antidiabetic Agents: Real-world Evidence from Large-scale Multinational Study

Ding, X.; Vadini, V.; Kim, C.; Bu, F.; Chen, H. Y.; Chai, Y.; Duarte-Salles, T.; Hsu, J. C.; Khera, R.; Lau, W. C. Y.; Man, K. K. C.; Nagy, P.; Ostropolets, A.; Pistillo, A.; Pratt, N.; Roel, E.; Seager, S.; Van Zandt, M.; Yuan, L.; Hripcsak, G.; Mathioudakis, N.; Suchard, M. A.; Nishimura, A.

2026-04-12 endocrinology 10.64898/2026.04.10.26350252 medRxiv
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Importance Women have been under-represented in clinical trials of type 2 diabetes mellitus (T2D), and evidence on sex differences in effectiveness of T2D treatments remains limited. Objective To assess sex differences in comparative effectiveness and safety of four second-line antidiabetic agents: glucagon-like peptide-1 receptor agonists (GLP-1RA), sodium-glucose cotransporter-2 inhibitors (SGLT2i), dipeptidyl peptidase-4 inhibitors (DPP4i), and sulfonylureas (SU). Design Retrospective cohort study using an active-comparator new-user design, following each participant till treatment discontinuation or end of data. Setting Multinational study across ten real-world databases from the Observational Health Data Sciences and Informatics (OHDSI) network in the United States, United Kingdom, Germany, and Spain. Participants 5.15 million adults with T2D who initiated one of the four second-line therapies following metformin during 1992-2021. Exposures GLP-1RA, SGLT2i, DPP4i, or SU. Main Outcomes and Measures Cardiovascular effectiveness as measured through 7 outcomes (major adverse cardiovascular events and glycemic control) and safety through 18 outcomes as highlighted by ADA guideline. Hazard ratios (HRs) are estimated separately for women and men using propensity score-stratified Cox models with empirical calibration. Sex differences were tested using Z-tests on log-HR differences. Results Drug initiation rates differed by sex with 9.28% of women initiating on GLP-1RA, 11.91% SGLT2i, 27.81% DPP4i, and 50.99% SU; the rates among the men were 5.41%, 12.84%, 24.64%, and 57.10%. No significant sex differences were observed for cardiovascular effectiveness outcomes. Several safety outcomes showed significant sex differences that are consistent across drug comparisons. Focusing on GLP-1RA compared to SGLT2i for brevity, GLP-1RA users experienced the following comparative benefits and risks: higher risk of acute pancreatitis among women (HR 1.39 [1.13, 1.70]) while non-differential risk among men (HR 0.91 [0.74, 1.12]) with p = 0.005 for the test of difference; non-differential risk of hypotension among women (HR 1.08 [0.98, 1.19]) while lower risk among men (HR 0.87 [0.78, 0.96]) with p = 0.003. Where no sex differences were found, our findings were consistent with existing evidence. Conclusions and Relevance This large-scale multinational study on antidiabetic agents identified clinically relevant sex differences, which are biologically plausible but previously lacked clinical evidence. Our findings reinforce the importance of tailoring T2D management according to sex.

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Current but Not Former Smoking Is Associated With Higher HbA1c in Adults Without Diabetes

Manafa, C. C.; Manafa, P. O.; Okoli, N.; Okafor-Udah, C. O.; Adilih, S.; Ogo, N.; Adilih, N.-a. A.

2026-04-17 endocrinology 10.64898/2026.04.10.26350673 medRxiv
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AimWe examined associations between smoking and HbA1c among U.S. adults, and whether these associations vary by diabetes status. MethodsWe analyzed NHANES data from 2015-2018 for adults aged [&ge;]20 years. Smoking was assessed by self-report and serum cotinine. Survey-weighted multivariable linear regression was used to evaluate the association between smoking and HbA1c in the full population (N=9,214) and in adults without diabetes (N=7,328), adjusting for demographics, blood pressure, waist circumference, lipids, and C-reactive protein. ResultsAfter adjustment for cardiometabolic covariates, there was no significant association between smoking and HbA1c in the full population (former: {beta}=0.029%, p=0.30; current: {beta}=0.053%, p=0.13). Among adults without diabetes, former smoking was not associated with HbA1c, whereas current smoking remained significantly associated (former: {beta}=-0.001%, p=0.923; current: {beta}=0.067%, p<0.001). These findings were similar when cotinine was used as the exposure measure, with active smoking ([&ge;]3.0 ng/mL) associated with higher HbA1c among non-diabetic adults (p<0.001), but not in the full population. ConclusionsAmong adults without diabetes, current but not former smoking was associated with higher HbA1c. The absence of an association in former smokers suggests that this effect may attenuate following cessation. These findings support early cessation interventions and may inform cessation counseling and diabetes screening.

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Probabilistic Cerebral Blood Flow Trajectories Across the Adult Lifespan Using Quantitative Water PET

Johansson, J.; Palonen, S.; Egorova, K.; Tuisku, J.; Harju, H.; Kärpijoki, H.; Maaniitty, T.; Saraste, A.; Saari, T.; Tuomola, N.; Rinne, J.; Nuutila, P.; Latva-Rasku, A.; Virtanen, K. A.; Knuuti, J.; Nummenmaa, L.

2026-04-11 radiology and imaging 10.64898/2026.04.08.26350393 medRxiv
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BackgroundQuantitative cerebral blood flow (CBF) measured with [15O]water positron emission tomography (PET) is the reference standard for quantifying brain perfusion. However, clinical interpretation of individual CBF measurements is limited by the absence of large normative datasets accounting for physiological variability across the adult lifespan. Long-axial field-of-view PET enables high-sensitivity quantitative [15O]water perfusion imaging without arterial blood sampling, allowing normative characterization of cerebral perfusion at unprecedented scale. The aim of this study was to establish normative and covariate-adjusted models of cerebral blood flow across the adult lifespan using total-body [15O]water PET. MethodsQuantitative CBF measurements were obtained in 302 neurologically healthy adults (age 21-86 years) using total-body [15O]water PET. Linear mixed-effects models were used to evaluate the effects of age, sex, body mass index (BMI), and blood hemoglobin concentration on CBF and to generate normative prediction models across the adult lifespan. Between-subject and within-subject variability were estimated from repeated scans in a subset of participants (n=51). ResultsMean grey matter CBF was 46.1 mL/(min*dL), with substantial inter-individual variability but high within-subject reproducibility (intraclass correlation coefficients 0.78-0.89). Advancing age was associated with a decline in CBF of approximately 7% per decade (p_FDR < 10-12). Higher BMI was associated with lower CBF (approximately -6% per 10 kg/m2; p_FDR < 0.01). Women exhibited higher CBF than men (approximately 7.5%), but this difference was largely explained by lower blood hemoglobin concentration in women. Covariate-adjusted models were used to generate normative predictions and prediction intervals describing expected CBF across adulthood. ConclusionThis study establishes a normative database of quantitative cerebral blood flow across the adult lifespan using high-sensitivity [15O]water PET. Age, BMI, and hemoglobin are major determinants of inter-individual variability in CBF. The resulting generative models provide a quantitative reference framework for interpreting cerebral perfusion measurements and may enable automated detection of abnormal brain perfusion in clinical PET imaging.

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Multi-task deep learning integrating pretreatment MRI and whole slide images predicts induction chemotherapy response and survival in locally advanced nasopharyngeal carcinoma

Hou, J.; Yi, X.; Li, C.; Li, J.; Cao, H.; Lu, Q.; Yu, X.

2026-04-11 radiology and imaging 10.64898/2026.04.07.26350350 medRxiv
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Predicting response to induction chemotherapy (IC) and overall survival (OS) is critical for optimizing treatment in patients with locally advanced nasopharyngeal carcinoma (LANPC). This study aimed to develop and validate a multi-task deep learning model integrating pretreatment MRI and whole slide images (WSIs) to predict IC response and OS in LANPC. Pretreatment MRI and WSIs from 404 patients with LANPC were retrospectively collected to construct a multi-task model (MoEMIL) for the simultaneous prediction of early IC response and OS. MoEMIL employed multi-instance learning to process WSIs, PyRadiomics and a convolutional neural network (ResNet50) to extract MRI features, and fused multimodal features through a multi-gate mixture-of-experts architecture. Clustering-constrained attention multiple instance learning and gradient-weighted class activation mapping were applied for visualization and interpretation. MoEMIL effectively stratified patients into good and poor IC response groups, achieving areas under the curve of 0.917, 0.869, and 0.801 in the train, validation, and test sets, respectively, and outperformed the deep learning radiomics model, the pathomics model and TNM staging. The model also stratified patients into high- and low-risk OS groups (P < 0.05). MoEMIL shows promise as a decision-support tool for early IC response prediction and prognostication in LANPC. Author SummaryWe have developed a deep learning model that integrates two types of medical images, including magnetic resonance imaging (MRI) and digital pathological slices, to simultaneously predict response to induction chemotherapy and prognosis in patients with locally advanced nasopharyngeal carcinoma. Current treatment decisions primarily rely on traditional tumor staging (TNM), which often fails to comprehensively reflect the complexity of the disease. Our model, named MoEMIL, was trained and tested on data from 404 patients across two hospitals and consistently outperformed both single-model approaches and TNM staging methods. By identifying patients who exhibit poor response to induction chemotherapy or higher prognostic risk, our tool can assist clinicians in achieving personalized treatment, enabling intensified management for high-risk patients and avoiding unnecessary side effects for low-risk patients. Additionally, we visualize the models reasoning process through heat map generation, which highlights the image regions exerting the greatest influence on prediction outcomes. This work represents a step toward more precise treatment for nasopharyngeal carcinoma; however, larger-scale prospective studies are required before the model can be integrated into routine clinical practice.

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Ultraprocessed foods elicit distinct metabolic and neural responses when compared to non-ultraprocessed foods

Hutelin, Z.; Ahrens, M.; Baugh, M. E.; Nartey, E.; Herald, D. L.; Hanlon, A. L.; DiFeliceantonio, A. G.

2026-04-11 nutrition 10.64898/2026.04.10.26350599 medRxiv
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Dietary patterns worldwide have shifted toward increased consumption of ultraprocessed foods (UPFs), which has been linked to higher disease burden. One mechanism proposed to impact both their consumption and contribution to metabolic disease is altered post-ingestive metabolic response in comparison to nutritionally similar foods. Here, we recruited 57 healthy-weight 18-45-year-old adults to examine the effects of food processing on postprandial metabolism and brain response. Despite nutritional matching, UPF meals evoked a greater insulinemic and energetic response with attenuated carbohydrate oxidation relative to non-UPF meals. Next, between-condition differences in peak carbohydrate oxidation were associated with mesolimbic and superior temporal gyrus activation in response to food cues. Finally, although food value did not differ between conditions, brain responses correlated with food valuation were positive for non-UPF but negative for UPF in visual cortex and striatum. These findings demonstrate that food processing influences post-ingestive metabolism in a way that could help explain long term health effects and differences in food reward through mechanisms beyond calories and macronutrient composition alone.

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Greater lean-body-mass decline with tirzepatide than semaglutide in routine care, revealed by body-composition digital phenotyping

Murugadoss, K.; Venkatakrishnan, A.; Soundararajan, V.

2026-04-13 endocrinology 10.64898/2026.04.11.26350687 medRxiv
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GLP-1 receptor agonists induce substantial weight loss, but the extent to which lean tissue and physical function are preserved in routine care remains poorly understood. Using an EHR-linked body-composition digital phenotyping pipeline with LLM-based extraction, we performed a large-scale longitudinal analysis of 670,422 first-episode GLP-1RA users, including 456,742 treated with semaglutide and 213,680 treated with tirzepatide. Among these, 7,965 individuals with paired pre- and post-initiation body-composition measurements were analyzed over 12 months. Tirzepatide was associated with greater relative lean body mass (LBM) loss than semaglutide at each measured time point, with excess LBM losses of 1.1%, 1.5%, 1.3% and 2% at 3, 6, 9 and 12 months, respectively. A Depletive GLP-1 metabotype, defined as >20% total body weight (TBW) loss with >5% LBM loss, was significantly more frequent with tirzepatide than semaglutide during the first year of therapy (10.3% versus 6.7%, p<0.001). By contrast, a Prime GLP-1 metabotype, defined as >10% TBW loss with <5% LBM loss, was numerically more frequent with semaglutide than tirzepatide, but not significantly so (12.3% versus 11.8%, p=0.66). Higher drug dose and longer exposure were associated with progressively greater LBM decline in both treatment groups (both p<0.001). Among 3,746 examined EHR phenotypes, baseline musculoskeletal pain emerged as the most significant correlate of greater LBM loss (BH-adjusted q<0.001): cervicalgia (semaglutide, -4.1 percentage points; tirzepatide, -14.3 percentage points) and knee pain (semaglutide, -4.8 percentage points; tirzepatide, -13.4 percentage points), consistent with mobility-limited patients being more vulnerable to lean-tissue depletion during incretin therapy. Analysis of EHR notes for on-treatment functional features showed reduced exercise tolerance was the strongest correlate of greater LBM loss, increasing by 7.2 and 11.1 percentage points in semaglutide- and tirzepatide-treated patients, respectively. An independent analysis of all available Single-cell RNA-seq data from human musculature showed broader GIPR+ cellular distribution than GLP1R+ cells across immune, stromal, vascular, and contractile compartments, providing plausible biological context for the greater LBM loss observed in routine care with tirzepatide (dual GLP1R-GIPR agonist) relative to semaglutide (GLP1R-specific agonist). In this observational study, greater weight-loss efficacy did not necessarily translate into more favorable body-composition outcomes, underscoring the need for clinical decision-making and trial designs that maximize each patient's likelihood of achieving a Prime GLP-1 metabotype.

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Normal is All You Need: A Symmetry-Informed Inverse Learning Foundation Model for Neuroimaging Diagnostics

Wang, S.; Ayubcha, C.; Hua, Y.; Beam, A.

2026-04-12 radiology and imaging 10.64898/2026.04.10.26350553 medRxiv
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Background: Developing generalizable neuroimaging models is often hindered by limited labeled data which has led to an increased interest in unsupervised inverse learning. Existing approaches often neglect geometric principles and struggle with diverse pathologies. We propose a symmetry-informed inverse learning foundation model to address these shortcomings for robust and efficient anomaly detection in brain MRI. Methods: Our framework employs a reconstruction-to-embedding pipeline, trained exclusively on healthy brain MRI slices. A 2D U-Net uses a novel, symmetry-aware masking strategy to reconstruct a disorder-free slice. Difference maps are embedded into a 1024-dimensional latent space via a Beta-VAE. Anomaly scoring is performed using Mahalanobis distance. We evaluated generalization by fine-tuning on external lesion datasets, BraTS Africa (SSA), and the ADNI-derived Alzheimer disease cohort (Alz). Results: On the source metastasis (Mets) dataset, the framework achieved high performance (AB1+MSE: 99.28% accuracy, 99.79% sensitivity). Generalization to the external lesion dataset (SSA) was robust, with the Symmetry ROC configuration achieving 91.93% accuracy. Transfer to the Alzheimer dataset (Alz) was more challenging, achieving a peak accuracy of 70.54% with a high false-positive rate, suggesting difficulty in separating subtle, diffuse changes. Conclusion: The symmetry-informed inverse learning framework establishes a robust foundation model for neuroimaging, showing strong performance for focal lesions and successful generalization under domain shift. Limitations in diffuse neurodegeneration underscore the necessity for richer representations and multimodal integration to improve future foundation models.

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High Dietary Linoleic Acid Intake Suppresses Eicosapentaenoic Acid Status and Shifts Oxylipin Metabolism Towards Arachidonic Acid in Healthy Adults: A Randomized Controlled Trial

Sergeant, S.; Easter, L.; Mustin, T.; Ivester, P.; Legins, J.; Seeds, M. C.; Standage-Beier, C. S.; Cox, A.; Furdui, C. M.; Hallmark, B.; Chilton, F. H.

2026-04-13 nutrition 10.64898/2026.04.09.26350499 medRxiv
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The modern Western diet (MWD) provides high linoleic acid (LA) exposure, typically contributing 6-9% of total caloric intake. These high LA levels have fueled a longstanding debate regarding whether this dietary pattern confers benefit or risk. Importantly, LA intake is disproportionately elevated among lower socioeconomic populations due to greater reliance on industrial seed oils and ultra-processed foods. Despite decades of research, controlled dietary intervention studies directly evaluating the biological consequences of varying LA exposure remain limited. The current randomized, double-blind intervention compared the effects of a 12-week Low LA diet (2.5% energy) versus a High LA diet (10.0% energy) in healthy adults. Primary outcomes included plasma highly unsaturated fatty acid (HUFA) concentrations and ex vivo zymosan-stimulated whole-blood oxylipin generation. Fifty- two participants completed the intervention. High LA exposure resulted in a marked reduction in plasma n-3 eicosapentaenoic acid (EPA) concentrations compared with the LowLA arm. In contrast, levels of arachidonic acid (ARA), dihomo-gamma-linolenic acid (DGLA) and docosahexaenoic acid (DHA) did not differ by dietary LA exposure. Analysis of oxylipin species revealed that levels of EPA-derived relative to ARA-derived mediators were significantly reduced in the High LA arm. These findings reveal that higher dietary LA selectively suppresses EPA pools and EPA-derived oxylipins without altering ARA, shifting the lipid mediator balance toward a more n-6-dominant profile.

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Analytical Choices Impact the Estimation of Rhythmic and Arrhythmic Components of Brain Activity

da Silva Castanheira, J.; Landry, M.; Fleming, S. M.

2026-04-11 neuroscience 10.1101/2025.09.24.678322 medRxiv
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Brain activity comprises both rhythmic (periodic) and arrhythmic (aperiodic) components. These signal elements vary across healthy aging, and disease, and may make distinct contributions to conscious perception. Despite pioneering techniques to parameterize rhythmic and arrhythmic neural components based on power spectra, the methodology for quantifying rhythmic activity remains in its infancy. Previous work has relied on parametric estimates of rhythmic power extracted from specparam, or estimates of rhythmic power obtained after detrending neural spectra. Variation in analytical choices for isolating brain rhythms from background arrhythmic activity makes interpreting findings across studies difficult. Whether these current approaches can accurately recover the independent contribution of these neural signal elements remains to be established. Here, using simulation and parameter recovery approaches, we show that power estimates obtained from detrended spectra conflate these two neurophysiological components, yielding spurious correlations between spectral model parameters. In contrast, modelled rhythmic power obtained from specparam, which detrends the power spectra and parametrizes brain rhythms, independently recovers the rhythmic and arrhythmic components in simulated neural time series, minimising spurious relationships. We validate these methods using resting-state recordings from a large cohort. Based on our findings, we recommend modelled rhythmic power estimates from specparam for the robust independent quantification of rhythmic and arrhythmic signal components for cognitive neuroscience.

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Colibactin-associated mutations in the human colon appear to reflect anatomy and early exposure, not oncogenesis

Hiatt, L.; Peterson, E. V.; Happ, H. C.; Major-Mincer, J.; Avvaru, A.; Goclowski, C. L.; Garretson, A.; Sasani, T. A.; Hotaling, J. M.; Neklason, D. W.; Uchida, A. M.; Quinlan, A. R.

2026-04-15 genetic and genomic medicine 10.64898/2026.04.13.26350783 medRxiv
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Colorectal cancer (CRC) is the second leading cause of cancer death globally and the number one cause of cancer death in people under 50 years old. The reasons for the rise of early-onset CRC are unknown, and while anatomically distinct subtypes of CRC have substantial clinical and molecular associations, the etiology of region-specific disease, such as early-onset CRC's enrichment in the distal colon, remains unclear. Understanding regional mutagenesis may identify risk factors for this public health concern and CRC more broadly. To evaluate mutational dynamics across the premalignant colon, we performed whole-genome sequencing of 125 individual colon crypts taken from six standardized regions biopsied during colonoscopy, collected from 11 donors without polyps and 10 with polyps. We observed mutation spectra and accumulation rates consistent with previous whole-organ studies, with greater subclonal mutation capture enabled by experimental design. T>[A,C,G] mutations, which are associated with colibactin genotoxicity from pks+ Escherichia coli, were significantly enriched in the rectum of donors with and without polyps (adjusted p-values < 0.01). Moreover, when comparing findings to crypts from individuals with CRC and sequenced CRC tumors, we observed consistent enrichment of the colibactin-associated mutational signature "ID18" in the rectum in both normal colon crypts and CRC tumors, without significant difference in colibactin-specific single nucleotide variant or insertion-deletion burden in crypts across the three clinical groups (i.e., no polyp, polyp, and CRC). These findings argue against a causal or prognostic role for colibactin in CRC, instead indicating that the proposed association with early-onset disease reflects anatomic specificity rather than cancer-specific clinical relevance.

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APOE4 Allele Frequencies Show Dramatic Variation Across Indian Populations

Ramdas, S.; Kahali, B.

2026-04-13 genetic and genomic medicine 10.64898/2026.04.09.26350483 medRxiv
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The APOE {varepsilon}4 allele is the strongest genetic risk factor for Alzheimers Disease. However, its distribution across Indian populations is poorly characterized. We analyze APOE allele frequencies in 9,524 individuals from 83 distinct populations in the GenomeIndia dataset. {varepsilon}4 frequencies show large variation across populations within India, ranging from 2.7% to 36.1%, with a median of 11%. Tribal populations have higher {varepsilon}4 frequencies compared to non-tribal groups, while Tibeto-Burman populations have significantly lower frequencies. One tribal population from the northern coastal highlands has {varepsilon}4 frequency of 0.36, with 59% of individuals being carriers. {varepsilon}4 carrier status correlates significantly with lipid phenotypes including LDL, HDL, total cholesterol, and triglycerides. Collectively, these findings reveal exceptional genetic diversity in Alzheimers Disease risk across India and have important implications for population-specific screening strategies, genetic counseling, and precision medicine approaches to dementia prevention.

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WITHDRAWN: Detection of Measles Virus RNA in Wastewater: Monitoring for Wild-Type and Vaccine-Derived Strains in a National Preparedness Trial

Ahmed, W.; Gebrewold, M.; Verhagen, R.; Koh, M.; Gazeley, J.; Levy, A.; Simpson, S.; Nolan, M.

2026-04-13 epidemiology 10.64898/2026.04.09.26350527 medRxiv
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Wastewater surveillance (WWS) is established as a vital tool for monitoring polio and SARS-CoV-2 with potential to improve surveillance for many other infectious diseases. This study evaluated the feasibility of detecting measles virus (MeV) RNA in wastewater as part of a national WS preparedness trial in Brisbane, Australia, from March to June 2025. Composite and passive sampling methods were employed in parallel at three wastewater treatment plants serving populations between 230,000 and 584,000. Nucleic acids were extracted and analyzed using RT-qPCR targeting MeV N and M genes to distinguish wild-type and vaccine strains. MeV RNA were detected in both 24-hour composite and passive samples on May 26 to 27, 2025 from the largest catchment of 584,000 which also included an international airport. No measles cases were reported in this city or region within 4 weeks of the WS detections. These were confirmed as vaccine-derived measles virus (MeVV) strain via specific RT-qPCR assay. Extraction recoveries varied (11.5% to 70.5%), with passive sampling showing higher efficiency. This is the first report of use of passive samples for detection of MeV. These findings are consistent with other studies reporting WWS results of both MeVV genotype A and wild type genotype B and/or D. It demonstrates the potential for sensitive MeV WWS with rapid differentiation of MeVV from wild type MeV shedding, including in airport transport hubs and with different sample types. Use of WWS could strengthen measles surveillance by enabling rapid detection of MeV RNA and supporting outbreak preparedness and response. This requires optimised methods which are specific to or differentiate wild-type MeV from MeVV. Furthermore, the successful detection of MeV using passive sampling in this study highlights its potential for deployment in diverse global contexts which may include non-sewered settings.