Individual Variation Research Articles

Individual variability in lactate response to cycling prescribed using physiological thresholds and peak work rate: a crossover within-participant repeated measures study.

(1) To determine if the blood lactate concentration ([BLa]) response is a repeatable individual trait, and (2) To examine whether threshold-based prescription (THR) reduces interindividual variability in [BLa] response compared to traditional (maximally anchored) exercise prescription (TRAD). A crossover within-participant repeated measures design was used to assess [BLa] during the TRAD and THR exercise in 17 participants (9M/8F). Participants initially undertook an incremental test to exhaustion to determine peak work rate (WRpeak), a lactate threshold (LT) test and a critical power (CP) test. All baseline tests were repeated twice. Participants then completed 6 15-min bouts of continuous cycling at 65%WRpeak (TRAD; 3 bouts) and 80% of the difference (Δ80) between LT and CP (THR; 3 bouts). [BLa] response was measured at 10 and 15min of exercise. Across individuals, there was a wide range in [BLa] response, but within individual responses were repeatable. [BLa] ranges and mean individual 90% confidence interval width (CIw) were as follows: TRAD@10min = 2.1-9.7mmol, CIw = 0.5mmol, THR@10min = 3.4-9.3mmol, CIw = 0.6mmol, TRAD@15min = 2.2-9.9mmol, CIw = 0.6mmol, THR@15min = 3.6-12.3mmol, CIw = 0.7mmol. Levene's tests revealed no significant differences in the variability of [BLa] response between TRAD and THR at 10min (F = 0.523, p = 0.475) or 15min (F = 0.351, p = 0.558) of exercise. Our results demonstrate that true interindividual variability in the [BLa] response to exercise exists, but failed to confirm that variability in [BLa] response is reduced with the use of THR.

Surgical treatment for hepatocellular carcinoma in era of multidisciplinary strategies.

Hepatocellular carcinoma (HCC) remains a significant global health challenge, with over 800,000 new cases diagnosed annually. This comprehensive review examines current surgical approaches and emerging multidisciplinary strategies in HCC treatment. While traditional surgical criteria, such as the Barcelona Clinic Liver Cancer (BCLC) staging system, have been relatively conservative, recent evidence from high-volume Asian centers supports more aggressive surgical approaches in carefully selected patients. The review discusses the evolution of selection criteria, including the new "Borderline Resectable HCC" classification system, which provides more explicit guidance for surgical decision-making. Technical innovations have significantly enhanced surgical precision, including three-dimensional simulation, intraoperative navigation systems, and the advancement of minimally invasive approaches. The review evaluates the ongoing debate between anatomical versus non-anatomical resection and examines the emerging role of robotic surgery. In liver transplantation, expanded criteria beyond the Milan criteria show promising outcomes, while the integration of novel biomarkers and imaging techniques improves patient selection. The role of preoperative and adjuvant therapies is increasingly important, with recent trials demonstrating the potential of immune checkpoint inhibitors combined with anti-VEGF agents in both settings. Despite these advances, postoperative recurrence remains a significant challenge. The review concludes that successful HCC treatment requires a personalized approach, integrating surgical expertise with emerging technologies and systemic therapies while considering individual patient factors and regional variations in practice patterns.

The drivers of intimacy toward social media-based brand communities: perspective of attachment theory

PurposeSocial media-based brand communities (SMBBCs) have emerged as one of the most significant marketing tools due to their ability to create and maintain close relationships between SMBBCs and consumers. However, past studies have ignored intimacy toward SMBBCs, particularly the role of individual variances in their development. Researchers have revealed the significant impacts of individual differences in attachment styles on the development of brand–consumer relationships based on attachment theory. Accordingly, this study aims to explore the drivers of intimacy toward SMBBCs from the perspective of attachment theory.Design/methodology/approachThis study examines a proposed model that integrates two attachment styles – attachment avoidance and attachment anxiety – self-disclosure on social media and intimacy toward SMBBCs through two samples in the context of brands’ Facebook fan pages.FindingsThe results show that attachment avoidance and attachment anxiety have significantly negative and positive effects on self-disclosure on social media, respectively, which contribute to intimacy toward SMBBCs.Practical implicationsThe results offer brand managers significant implications for segmenting markets and developing relationship marketing strategies for their brand communities on social media.Originality/valueThis study is the first attempt to explore the driving factors of intimacy toward SMBBCs from the attachment theory perspective.

Longitudinal Assessment of Subclinical Arterial Inflammation in Patients Receiving Immune Checkpoint Inhibitors by Sequential [18F]FDG PET Scans.

Immune checkpoint inhibitors (ICIs), though revolutionary in cancer treatment, may accelerate atherosclerosis by inducing arterial inflammation. Due to a lack of controlled studies, the capacity of arterial 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake in patients with cancer to detect this arterial inflammation remains unclear. Arterial [18F]FDG uptake at 6 anatomic landmarks was assessed on serial positron emission tomography scans in patients with cancer treated at a German University Hospital between January 2010 and May 2023. Patients aged ≥65 years with at least 4 sequential scans within 30 months were included. Linear mixed regression analyses were used to evaluate the change in arterial tracer uptake in patients who received ICI or not. Of the 156 patients included, 50 (30.1%) received ICIs after the baseline scan. Baseline arterial [18F]FDG uptake correlated with traditional cardiovascular risk factors, such as body mass index and male sex. Cross-sectional analyses suggested a negative effect of cholesterol-lowering medication on arterial [18F]FDG uptake at follow-up. In a time-dependent interaction analysis, arterial [18F]FDG uptake increased by 0.8% annually in patients without ICIs (95% CI, 0.2%-1.4%), potentially reflecting the background progression of arterial inflammation in patients with cancer. In ICI users, [18F]FDG uptake increased by 2.5% annually (95% CI, 1.7%-3.3%; P=0.001 for interaction with no ICI). Higher annual increase rates in ICI users were consistent across several anatomic landmarks, preexisting cardiovascular disease status, arterial calcification status, and concomitant chemotherapy or steroid use. However, this effect did not reach statistical significance in patients with melanoma and those with prior irradiation therapy. This is the first controlled clinical study supporting the role of ICIs in accelerating atherosclerosis through low-grade arterial inflammation. However, although detectable by repeated [18F]FDG scans, the increase in tracer uptake associated with ICI use was modest compared with individual variability, questioning whether [18F]FDG captures the full pathophysiological process of ICI-induced, lymphocyte-driven inflammation.

Deep, Unbiased, and Quantitative Mass Spectrometry-Based Plasma Proteome Analysis of Individual Responses to mRNA COVID-19 Vaccine.

Global campaign against COVID-19 have vaccinated a significant portion of the world population in recent years. Combating the COVID-19 pandemic with mRNA vaccines played a pivotal role in the global immunization effort. However, individual responses to a vaccine are diverse and lead to varying vaccination efficacy. Despite significant progress, a complete understanding of the molecular mechanisms driving the individual immune response to the COVID-19 vaccine remains elusive. To address this gap, we combined a novel nanoparticle-based proteomic workflow with tandem mass tag (TMT) labeling, to quantitatively assess the proteomic changes in a cohort of 12 volunteers following two doses of the Pfizer-BioNTech mRNA COVID-19 vaccine. This optimized protocol seamlessly integrates comprehensive proteome analysis with enhanced throughput by leveraging the enrichment of low-abundant plasma proteins by engineered nanoparticles. Our data demonstrate the ability of this workflow to quantify over 3,000 proteins, providing the deepest view into COVID-19 vaccine-related plasma proteome study. We identified 69 proteins with boosted responses post-second dose and 74 proteins differentially regulated between individuals who contracted COVID-19 despite vaccination and those who did not. These findings offer valuable insights into individual variability in response to vaccination, demonstrating the potential of personalized medicine approaches in vaccine development.

Effect of sleep deprivation on gait complexity.

Gait complexity is considered an indicator of adaptability, reflecting the complex interaction between multiple components of the neuromuscular system. Previous research provided evidence that chronobiology, which reflects the individual expression of circadian rhythms, affects the regulation of gait dynamics. The literature also suggests the disruption of these circadian rhythms affects multiple human physiological systems. Considering the association between chronobiology and gait complexity, and its clinical relevance, it would be important to investigate whether the disruption of sleep-wake cycle could affect gait complexity. This study aimed to investigate the effect of 1 night of sleep deprivation on gait complexity and variability of healthy individuals, exploring potential implications for motor control. Seventeen healthy and young male adults underwent an in-lab supervised 24-hr sleep deprivation protocol, with gait complexity and variability assessed using detrended fluctuation analysis and coefficient of variation, respectively. Chronotype was also assessed through the Morningness-Eveningness Questionnaire. We observed a loss of gait complexity with sleep deprivation (PRE: 0.8 ± 0.13; POST24: 0.62 ± 0.08, p < 0.001), while gait variability remained unaltered (p = 0.132). Additionally, we demonstrated an association between gait complexity's relative changes and chronotype (r = -0.665, p = 0.004). Overall, our findings suggest sleep deprivation induces a decrease in the neuromuscular system's ability to flexibly adapt gait output. Moreover, we also highlight the importance of chronobiology in motor control, as we observed the more morning-type an individual is, the greater the loss of complexity following 1 night of sleep deprivation. Altogether, our findings underscore the potential impact of sleep deprivation on central processes underlying gait complexity.

Memory deficits in children and adolescents with a psychotic disorder: a systematic review and meta-analysis.

Early-onset psychosis (EOP) is a severe disorder which takes place before 18years. It entails diverse clinical and functional implications, and it may lead to critical impairments in neurocognitive functions. Although deficits in memory are well described in adult populations and they appear to be clinically related with psychosis, impairments in memory in EOP show inconsistencies between studies. This study aimed to gain insight into the relationship between EOP and memory impairments, studying the potential contribution of moderators (storage source and memory content) on the observed memory deficits. This systematic review and meta-analysis was conducted following the PRISMA-2020 guidelines. Search was conducted in English and Spanish in five databases. Case-control studies which met all requirements were selected. Overall effect size was calculated under the random-effects model and Z-based tests were used. Heterogeneity was analysed by the I2 statistic. Mixed-effects meta-regression analysis was used to study the influence of methodological quality of studies, mean age, proportion of female participants within sample, mean diagnosis, memory storage type, memory content as moderators on individual effect size variability. As a result, 32 articles were finally selected, pooling data from 2636 participants (49.29% EOP participants). Overall effect size was Hedges' g = - 1.01, CI95 = [ - 1.35, - 0.67], p < .01, indicating lower memory performance in the EOP group in comparison to healthy controls. Diagnosis and memory storage were found as significant moderators in the memory performance variance: larger deficits were found in children with psychosis and in working memory tasks.

Hyperthermia and targeting heat shock proteins: innovative approaches for neurodegenerative disorders and Long COVID

Neurodegenerative diseases (NDs) and Long COVID represent critical and growing global health challenges, characterized by complex pathophysiological mechanisms including neuronal deterioration, protein misfolding, and persistent neuroinflammation. The emergence of innovative therapeutic approaches, such as whole-body hyperthermia (WBH), offers promising potential to modulate underlying pathophysiological mechanisms in NDs and related conditions like Long COVID. WBH, particularly in fever-range, enhances mitochondrial function, induces heat shock proteins (HSPs), and modulates neuroinflammation—benefits that pharmacological treatments often struggle to replicate. HSPs such as HSP70 and HSP90 play pivotal roles in protein folding, aggregation prevention, and cellular protection, directly targeting pathological processes seen in NDs like Alzheimer's, Parkinson's, and Huntington's disease. Preliminary findings also suggest WBH's potential to alleviate neurological symptoms in Long COVID, where persistent neuroinflammation and serotonin dysregulation are prominent. Despite the absence of robust clinical trials, the therapeutic implications of WBH extend to immune modulation and the restoration of disrupted physiological pathways. However, the dual nature of hyperthermia's effects—balancing pro-inflammatory and anti-inflammatory responses—emphasizes the need for dose-controlled applications and stringent patient monitoring to minimize risks in vulnerable populations. While WBH shows potential interest, significant challenges remain. These include individual variability in response, limited accessibility to advanced hyperthermia technologies, and the need for standardized clinical protocols. Future research must focus on targeted clinical trials, biomarker identification, and personalized treatment strategies to optimize WBH's efficacy in NDs and Long COVID. The integration of WBH into therapeutic paradigms could mark a transformative step in addressing these complex conditions.

Mapping Inflammatory Markers in Cerebrospinal Fluid Following Aneurysmal Subarachnoid Hemorrhage: An Age- and Sex-Matched Analysis

Despite extensive research on aneurysm treatment and neurocritical care, aneurysmal subarachnoid hemorrhage (SAH) is still a life-threatening disease, often leaving survivors with lasting neurological and cognitive impairments. Early brain injury (EBI) and delayed cerebral ischemia (DCI) are the main contributors to brain damage, with neuroinflammation being a critical shared pathophysiological process. While numerous inflammatory markers and their temporal profiles in cerebrospinal fluid (CSF) have already been identified, comparisons with age- and sex-matched controls are limited. This study analyzed CSF from 17 SAH patients requiring an external ventricular drain (EVD) due to symptomatic hydrocephalus, sampled on days 4 and 10 post-ictus. An age- and sex-matched control group included 17 cerebrovascularly healthy patients requiring lumbar drains during aortic surgery. Chemokines and cytokines were quantified using immunoassays. Significantly elevated markers in SAH patients across both time points included MCP-1, CXCL-13, Eotaxin-1, CXCL-10, IL-8, and MIF. MIP-1α and MIP-1β showed significant differences at particular time points, indicating a distinct temporal profile for each parameter. These findings highlight neuroinflammation’s key role in intracranial and systemic pathophysiology following SAH, emphasizing its complexity and individual variability. Knowing demographic factors impact the specific manifestations of pathophysiological processes, the comparison with an age- and sex-matched control group is meaningful.

Boar-to-Boar Variations in Quality Characteristics of Sperm from Different Ejaculates Following Freezing–Thawing

The main objective of this study was to investigate boar-to-boar variations in the quality characteristics of sperm from the sperm-rich fractions (SRFs) and whole ejaculates (WEs) following freezing–thawing. Several sperm attributes, such as motility patterns analyzed by the computer-assisted sperm analysis (CASA) system, mitochondrial function, membrane integrity, and DNA fragmentation were used to compare the cryo-survival of sperm from SRFs and WEs from boars with good and poor semen freezability (GSF and PSF, respectively). In this study, boars with post-thaw total motility (TMOT) more than 30% (&gt;30%) were classified as having GSF, while those with post-thaw TMOT less than 30% (&lt;30%) were classified as having PSF. Principal component analysis 1 (PCA1), which is the main component of the sample variation, explained approximately 75% of the variance between the GSF and PSF groups, reaffirming the reliability of post-thaw TMOT as a reliable criterion used to classify the animals. Most of the post-thaw sperm parameters of the SRFs and WEs were positively correlated. Furthermore, scatter plot analyses show stronger relationships between the analyzed post-thaw parameters of the frozen–thawed (FT) sperm of SRFs than those of WEs. Individual boar variations or the sperm source had marked effects on the quality characteristics of FT sperm. The higher TMOT, velocity straight line (VSL), and velocity average path (VAP) of FT sperm were more enhanced in the SRFs compared with the WEs of the PSF group. Furthermore, the mitochondrial function, membrane integrity, and DNA fragmentation of FT sperm were markedly higher in the SRFs than in the WEs, particularly for the poor freezability boars. We suggest that the freezability potential of sperm of the GSF group does not differ significantly between the SRFs and WEs, reaffirming that boar variability is an important factor that affects the cryo-survival of sperm.

Different social experiences drive the development of divergent stress coping styles in female swordtails (Xiphophorus nigrensis).

Individual variation in stress coping styles is widespread and consequential to health and fitness. Proactive (bold behavior, low stress reactivity, low cognitive flexibility) and reactive (shy behavior, high stress reactivity, high cognitive flexibility) coping styles are found in many species, but the developmental forces shaping them remain elusive. We examined how social influences, specifically mating interactions, shape the development of adult female coping styles with a manipulative rearing experiment using El Abra swordtails, Xiphophorus nigrensis. We raised juvenile females in environments with different male reproductive phenotypes: coercive-only, courting-only, or complex (both coercive and courting males). At adulthood, we measured female stress reactivity (cortisol release following acute stress), boldness (scototaxis and open field responses), and cognitive flexibility (as inhibitory control in a detour task). Females raised in coercive and complex environments developed higher cortisol reactivity than females raised with only courtship. Stress coping trait correlations varied significantly across social environments producing different coping styles across treatments. Traditional proactive and reactive stress coping styles developed in the coercive-only environment with negative correlations between stress response and boldness, stress response and cognitive flexibility, and boldness and cognitive flexibility. Meanwhile, the courtship-only environment produced a negative correlation between stress response and boldness. We thus demonstrate that the relationship between stress response and boldness can be socially modulated. These findings suggest that developmental variation in social experiences can shape suites of traits with complex relationships; and that highly stressful social interactions, such as sexual coercion, can be a strong driver of stress coping styles.

Individual Variability in Cortical Representations of Tonic Pain

Individual Variability in Cortical Representations of Tonic Pain

Drivers of individual differences in the sleep behaviour of fallow deer neonates.

Inter-individual differences are necessary for selection to act, while plasticity (intra-individual variation) may buffer against selection. Sleep is a critical self-maintenance behaviour but, unlike most behaviours, the causes and consequences of its inter- and intra-individual variation in wild animals is poorly understood, particularly in neonates where sleep plays a key role in development. We have shown previously that free-ranging neonate fallow deer (Dama dama) differ in sleep during the first few weeks of life. Here, we test whether individual variability in sleep is organised systematically across the population, and whether these individual differences are associated with chronic stress measured using hair cortisol, or the timing of birth. Four dimensions of sleep behaviour (total sleep time, sleep fragmentation, sleep quality, and sleep distribution over 24-h) were quantified using state-of-the-art triaxial accelerometers. We then used a multivariate mixed-effects model in a Bayesian framework to evaluate covariation between multiple dimensions of sleep behaviour, and quantify the relative importance of chronic stress and the timing of birth, while accounting for the confounding effects of environmental conditions and age. We found that the timing of birth and chronic stress were not associated with changes in sleep between individuals. While both total sleep time and the number of bouts per day declined with age, their rate of development covaried, but no other sleep dimensions covaried. Our results represent an in-depth analysis of natural variation in sleep, and show that individual differences in four aspects of sleep architecture in free-living fallow deer fawns are strong but independent of one another and unrelated to chronic stress or the timing of birth. We suggest that covariation between sleep dimensions might emerge later in life and effects of cortisol and birth timing might be very short and transient.

Reward Decision Network Disconnection in Poststroke Apathy: A Prospective Multimodality Imaging Study.

Apathy is a common neuropsychiatric symptom following stroke, characterized by reduced goal-directed behavior. The reward decision network (RDN), which plays a crucial role in regulating goal-directed behaviors, is closely associated with apathy. However, the relationship between poststroke apathy (PSA) and RDN dysfunction remains unclear due to apathy heterogeneity, the confounding effect of depression and individual variability in lesion impacts. This study aims to dissect the heterogeneity of PSA and explore the link between lesion-induced RDN damage and PSA. We prospectively recruited 207 patients with acute ischemic infarction and 60 demographically matched healthy controls. Participants underwent neuroimaging and longitudinal neuropsychiatric assessments. To characterize PSA heterogeneity, we employed multivariate analysis and clustering algorithms based on whole-brain functional connectivity and clinical assessments to classify patients into different PSA biotypes. We embedded each patient's lesion into a structural connectome atlas to obtain white matter (WM) disconnection maps. On this basis, WM disconnection scores were calculated for each brain region to quantify lesion-induced WM damage. We employed the XGBoost model to predict PSA biotypes based on WM disconnection scores, comparing the performance of models focusing on RDN-specific versus whole-brain WM disconnection. Additionally, we explored WM damage patterns across different biotypes by comparing disconnection scores in critical brain regions. We identified four PSA biotypes with unique clinical trajectories and neurobiological underpinnings. Biotype 4 was characterized by persistent apathy with depressive symptoms. Biotype 2 showed persistent apathy. Biotype 3 was non-apathetic. Biotype 1 exhibited delayed-onset apathy. The XGBoost models, when focused on the RDN-specific WM disconnection, performed significantly better in predicting PSA biotypes compared to the whole-brain WM disconnection model (t(164.66) = 8.871, p < 0.001). Analysis of WM disconnection patterns revealed that Biotype 4 exhibited more extensive RDN damage in crucial regions, Biotype 1 had a unique pattern of damage in the anterior cingulate cortex (t(61) = 1.874, p = 0.032), and Biotype 2 had a unique pattern of damage in the orbitofrontal cortex (t(53)= 1.827, p = 0.036). This study dissected PSA heterogeneity and demonstrated that RDN damage is a critical factor in PSA variability. We found that lesion-induced WM disconnections in anterior cingulate cortex and orbitofrontal cortex can lead to delayed-onset and persistent apathy, respectively. Furthermore, our findings revealed that apathy not only has distinct pathogenic mechanisms, but also shares neurobiological substrates with depression.

Person-specific characteristics of people with low back pain moderate the movement pattern within motor skill training and strength and flexibility exercise: Secondary analysis of a randomized clinical trial

People with low back pain (LBP) display an altered movement pattern during functional activities. Exercise-based treatments improve the altered pattern, but there is individual variability in the response to treatment. This study investigates the moderating effect of person-specific characteristics on a movement pattern at baseline and change over time in the pattern in people with chronic LBP who received motor skill training (MST) or strength and flexibility exercise (SFE). Kinematic data were collected at baseline, immediately post-treatment, and 6 months post-treatment. Lumbar contribution (LC) to total movement was used to quantify the magnitude of the altered movement pattern. Hierarchical linear modeling was used to explore the moderating effects of treatment group, age, sex, duration of LBP, and baseline LC on 1) baseline LC and 2) the change in LC over time. We found that person-specific characteristics moderated the change over time in LC within MST. Older people had a smaller change over time in LC and did not retain the improved pattern as well as younger people (β = 0.01, SE = 0.004, p < 0.01).

Refining colorectal cancer screening strategies using polygenic risk scores and classical risk factors: A proof-of-concept study in the UK Biobank cohort.

104 Background: While the rising incidence of CRC in younger populations has led to a push for lowering the screening age to 40, current clinical guidelines lack sufficient consideration of individual risk variations, raising concerns about the potential harms of over-diagnosis and false positives. Our proof-of-concept study evaluates the utility of risk stratification for multi-target stool DNA (mt-sDNA) testing by integrating polygenic risk scores and traditional clinical risk factors, addressing gaps in current clinical CRC screening guidelines. Methods: Our study utilized the UK Biobank prospective cohort, consisting of 311,544 unrelated individuals of White British ancestry, aged 40-69, excluding those with any prior malignant cancer diagnosis. We developed a sex-specific Cox proportional hazards model to estimate the risk of developing CRC, with the primary outcome being the first incidence of CRC. Three models were assessed: a polygenic risk score (PRS)-only model, a classical risk factors (RF)-only model, and a combined (PRS + RF) model. The traditional risk factors considered were BMI, smoking status, pack years of smoking, and family history of bowel cancer in first-degree non-adoptive relatives. Model performance was evaluated using the area under the curve (AUC), hazard ratios (HR), and the positive and negative predictive values of mt-sDNA across various risk profiles. Results: The combined model for early CRC screening using mt-sDNA demonstrated superior risk stratification (Table) and improved PPV compared to the risk factors-only model, with enhanced performance even among younger individuals at lower baseline risk. If risk stratification was not used, the average PPV for the test in the general population (ages 40-80) would be 2.13% for males and 1.44% for females. In contrast, individuals in the top 1% of risk would have significantly higher PPVs: 5.62% for males and 3.51% for females. If we limit testing to only the high-risk group, per 100,000 individuals, approximately 3,490 additional cases for males and 2,070 additional cases for females would be detected compared to the average-risk population without stratification. Conclusions: The findings suggest that risk stratification may enhance the effectiveness of screening by identifying high-risk individuals who would derive the greatest benefit. In contrast, broad application of the test across the general population may not achieve an optimal risk-benefit ratio, given the relatively low PPV in average-risk individuals. Model performance of the PRS-only, RF-only, and PRS + RF (Combined) models for females and males, respectively. Hazard Ratio (95% CI) C-index (SE) 5-Year AUC Female PRS-Only 1.50 (1.37 - 1.64) 0.62 (0.01) 0.61 RF + PRS 1.49 (1.36 - 1.63) 0.62 (0.01) 0.61 RF Only 1.09 (0.99 - 1.20) 0.53 (0.02) 0.51 Male PRS-Only 1.49 (1.38 - 1.61) 0.63 (0.01) 0.69 RF + PRS 1.49 (1.38 - 1.61) 0.64 (0.01) 0.71 RF Only 1.23 (1.15 - 1.31) 0.57 (0.01) 0.57

Systematic shifts in the variation among host individuals must be considered in climate-disease theory.

To make more informed predictions of host-pathogen interactions under climate change, studies have incorporated the thermal performance of host, vector and pathogen traits into disease models to quantify effects on average transmission rates. However, this body of work has omitted the fact that variation in susceptibility among individual hosts affects disease spread and long-term patterns of host population dynamics. Furthermore, and especially for ectothermic host species, variation in susceptibility is likely to be plastic, influenced by variables such as environmental temperature. For example, as host individuals respond idiosyncratically to temperature, this could affect the population-level variation in susceptibility, such that there may be predictable functional relationships between variation in susceptibility and temperature. Quantifying the relationship between temperature and among-host trait variation will therefore be critical for predicting how climate change and disease will interact to influence host-pathogen population dynamics. Here, we use a model to demonstrate how short-term effects of temperature on the distribution of host susceptibility can drive epidemic characteristics, fluctuations in host population sizes and probabilities of host extinction. Our results emphasize that more research is needed in disease ecology and climate biology to understand the mechanisms that shape individual trait variation, not just trait averages.

The relationship between AutoNRT thresholds and subjective programming levels revisited

Objectives The aim of this study wasto systemically examine the relationship between AutoNRT thresholds and subjective programming levels by controlling for individual subject variation, and further, to propose an alternative way to calculate the AutoNRT threshold profile for programming purposes. Methods The study was a prospective observational study. AutoNRT thresholds, T- and C-levels were recorded at six and twelve months after activation. All subjects had received a CI24RE implant. Results Forty-one adults participated in the study. A linear mixed-effects model analysis of the relationship between the AutoNRT thresholds and the T-and C-levels resulted in a large unexplainable variation between subjects, the standard deviation was between 15.42 and 18.89 CL. However, the study showed that the profiles for the T- and C-levels could be predicted with an acceptable accuracy from AutoNRT. A model for calculating profiles from AutoNRT thresholds based on linear regression resulted in the lowest deviation from the subjective programming thresholds, with somewhat better results for C-levels than T-levels. Conclusion The results from this study showed that the predictability was reasonable when calculating the profiles for the T- and C-levels based on AutoNRT. And, further, that AutoNRT thresholds can be used when programming cochlear implants, to make global adjustments without predicting actual T- or C-levels.

Adaptive Inert Gas Exchange Model for Improved Hypobaric Decompression Sickness Risk Estimation

INTRODUCTION: Future high-altitude military operations and spaceflight will require new procedures to protect crews from decompression sickness while limiting the operational impact. It is hypothesized that the current prediction models do not accurately reflect actual inert gas dynamics, making them unsuitable for the risk estimation of new hypobaric exposure profiles. METHODS: A biophysical gas exchange model was created, allowing modification of various physiological parameters. Predicted nitrogen (N2) volume flows were compared with an experimental study by the Swedish Aerospace Physiology Centre. Bubble growth predictions, made using the Tissue Bubble Dynamics Model, were compared with measured venous gas emboli (VGE). RESULTS: While the simulated washout curves captured the general trends, some important discrepancies were observed when using the nominal model parameters. The new biophysical gas exchange model, incorporating changes in cardiac output and individual anthropometric variations, improved the predictions and approximated the experimentally observed N2 washout. The standard bubble growth predictions did not match measured VGE. Using weighing factors based on the N2 gas flow components predicted by the new biophysical model, the bubble growth pattern agrees much better with the measured VGE scores. DISCUSSION: Traditional decompression models do not account for variations in physiological and environmental factors, leading to incorrect estimates of N2 washout and bubble growth predictions. Using an adaptive biophysical gas exchange model significantly improves the predictions for various altitude exposure profiles. We therefore strongly recommend incorporating adaptive physiological parameters in any model to be used for estimating decompression sickness risk and designing mitigation procedures. De Ridder S, Neyt X, Germonpré P. Adaptive inert gas exchange model for improved hypobaric decompression sickness risk estimation. Aerosp Med Hum Perform. 2025; 96(2):85–92.

Linking Multi-Dimensional Religiosity in Childhood and Later Adulthood: Implications for Later Life Health.

This study examines religiosity patterns across childhood and later adulthood and their associations with later-life health using an experimental module from the 2016 Health and Retirement Study (N = 1649; Mean Age = 64.0). Latent class analysis is used to categorize individuals by commonalities in religious attendance, religious identity, and spiritual identity. Cross-sectional and longitudinal associations are then explored using probable depression, disability, and mortality as health indicators. Results reveal complex patterns, often characterized by declining attendance and fluctuating identity. Relationships with health appear stronger in cross-sectional analyses, suggesting that some associations may be non-causal. Individuals with consistently strong religiosity show significantly better psychological health compared to their relatively non-religious counterparts. Moreover, the absence of religiosity in later adulthood is associated with an increased risk of mortality. Overall, the findings support the promotion of religiosity whilst acknowledging individual variations and highlighting the need for more individualistic approaches to the study of religion and health.