Fitness Consequences Research Articles

Correlation between serum hemoglobin levels and bone mineral density in adults: A cross-sectional study.

Serum hemoglobin plays an important role in bone metabolism. However, the association between serum hemoglobin levels and bone mineral density (BMD) remains unclear. Therefore, this study aimed to explore the relationship between serum hemoglobin levels and lumbar spine BMD in adults. We conducted a cross-sectional study by utilizing data from the National Health and Nutrition Examination Survey from 2011 to 2018. The serum hemoglobin level was examined as an independent variable, while the lumbar spine BMD was utilized as the dependent variable. Weighted multivariate linear regression models and stratified analysis by age, sex, and race/ethnicity were applied after controlling for confounding factors to assess the relationship between serum hemoglobin levels and the lumbar spine BMD. Additionally, smooth curve fitting and threshold effect analyses were utilized to depict the nonlinear relationship between the 2 variables. A total of 11,658 participants (6004 men and 5654 women) aged ≥ 18 years were included in this study. When the serum hemoglobin level was represented as a continuous variable and fully adjusted in the regression model, the hemoglobin level was significantly negatively correlated with the lumbar spine BMD (β = -0.0035, 95% confidence interval: -0.0065 to -0.0004, P = .024555); this significant negative correlation persisted when the serum hemoglobin level was transformed into a categorical variable, except in the Q2 group (β = -0.0046, 95% confidence interval: -0.0142 to -0.0050, P = .348413). When different confounding factors were used including sex, age, and race/ethnicity, the stratified subgroups exhibited a negative correlation between the serum hemoglobin level and the lumbar spine BMD. Additionally, smooth curve fitting and threshold effect analyses showed a negative correlation between the serum hemoglobin level and the lumbar spine BMD, with a saturation effect at 15 g/dL. Our findings demonstrated an association between hemoglobin levels and the lumbar spine BMD in adults, characterized by a nonlinear relationship. Thus, monitoring the serum hemoglobin level could aid in the early detection of risks associated with bone metabolic disorders such as osteoporosis.

The association between weight-adjusted waist index and sleep disorders in U.S. adults: results from NHANES 2005-2008.

The detrimental effects of obesity on sleep disorders have garnered a lot of interest. The weight-adjusted waist index (WWI) is a newly developed anthropometric index calculated in terms of weight and waist circumference. The body mass index has been employed to evaluate obesity in the majority of studies that connect obesity to sleep disorders. This study seeks to investigate the correlation between WWI and sleep disorders among adults in the United States. This cross-sectional study was part of the National Health and Nutrition Examination Survey and included adults aged >20 from 2005 to 2008. This study investigated the linear relationship between sleep disorders and WWI using weighted binary logistic regression models. Nonlinear relationships were characterized using smooth curve fitting and threshold effects analyses. After that, based on variables like gender, age, marital status, diabetes, hypertension, and smoking, subgroup analyses were performed. Our study included 9869 participants who were at least 20 years old. Higher WWI was linked to greater odds of sleep disorders prevalence, according to weighted binary logistic regression (odds ratio = 1.15; 95% confidence interval, 1.10, 1.20). In subgroup analyses based on age, marital status, diabetes, hypertension, and smoking, this connection remained robust. However, there were notable differences in this connection depending on gender. Furthermore, a nonlinear correlation with inflection points between WWI and sleep disorders was shown using smooth curve fitting. The nonlinear association between WWI and sleep disorders has an inflection point of 8.1 cm/√kg, as indicated by the threshold effect analyses. A higher WWI exposure may elevate the odds of sleep disorder prevalence, underscoring the importance of considering WWI in the prevention and management of sleep disorders.

Association between healthy lifestyle and frailty in adults and mediating role of weight-adjusted waist index: results from NHANES

BackgroundThe relationship between healthy lifestyle and frailty remains unclear. Healthy weight is crucial for overall well-being, but using body mass index (BMI) to evaluate weight management is inefficient. This study clarifies the association between healthy lifestyle or its factors (non-smoking, moderate drinking, healthy weight, healthy diet, sufficeint physical activity, and non-sedentary) and frailty, and the feasibility of using the weight-adjusted waist index (WWI) reflecting central obesity as an intermediate indicator.MethodsThis study included 4,473 participants from the 2007–2018 National Health and Nutrition Examination Survey (NHANES). Healthy lifestyle quality was assessed by summing the scores of each healthy lifestyle factor. Frailty was assessed using a 49-item frailty index (FI), categorizing participants into robust, pre-frail, and frail. Logistic regression to investigate the association between healthy lifestyle or its factors, WWI, and frailty. Smooth curve fitting and threshold effect analyses were used to elucidate the nonlinear association. Subgroup and two other sensitivity analyses were conducted to confirm the stability of the results. A causal mediation model examined the proportion of frailty mediated by WWI.ResultsThe study identified 13.98% of the participants as frail. Optimal healthy lifestyle and frailty were negatively associated (OR: 0.39, 95%CI: 0.27–0.58). Five healthy lifestyle factors (non-smoking, healthy weight, healthy diet, sufficient physical activity, and non-sedentary) were associated with a lower prevalence of frailty, with odds ratios (OR) ranging from 0.48 to 0.61. We also analyzed the association between a healthy lifestyle and WWI (OR: 0.32, 95%CI: 0.27–0.37), WWI and frailty (OR: 1.85, 95%CI: 1.59–2.16). A positive association between WWI and FI was observed beyond the inflection point (9.99) (OR: 0.03, 95%CI: 0.02–0.03). Subgroup and sensitivity analyses confirmed stable associations between healthy lifestyle, WWI, and frailty. WWI partially mediated the association between a healthy lifestyle and frailty (mediating ratio = 20.50–20.65%).ConclusionsAn optimal healthy lifestyle and positive healthy lifestyle factors are associated with a lower incidence of frailty. WWI may mediate the relationship between a healthy lifestyle and frailty.

Sex-specific manipulation of sexually cannibalistic mantid mating behavior by hairworms

Abstract Changes in the morphology, physiology, and behavior of parasitized organisms provide an ideal opportunity to examine the extended phenotype of parasites. Because the quality of the host directly affects the fitness of the parasite, parasites may increase their fitness by manipulating phenotypes of low-quality hosts. Males are usually preyed on by females in sexual cannibalism. Thus, the males of sexually cannibalistic species are unsafe and low-quality hosts for parasites, whereas females may be beneficial hosts because of the chance of nutrient intake from cannibalized males. Under passive modes of transmission, parasites cannot choose the host sex. Such parasites exploiting sexually cannibalistic organisms are subjected to contrasting fitness effects and may evolve to manipulate host mating behavior in a sex-specific manner: decreasing male mating to avoid cannibalism and promoting female mating to engage in cannibalism. We examined this hypothesis by a behavioral experiment using a mantid–hairworm system. Parasitized male mantids (Tenodera angustipennis) changed their behavior as expected, exhibiting increased escapes and decreased courtships and mountings, potentially avoiding encounters with the female. Interestingly, male attack behavior was promoted, possibly decreasing contact with the encountered female. However, contrary to our prediction, parasitized females also exhibited decreased propensities of mating, suggesting costs or little benefits of host mating for parasites in the female host. This study provides novel insights into the evolution of parasite strategies in response to sexual differences in host quality.

The association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and chronic obstructive pulmonary disease: the mediating role of dietary inflammatory index.

Numerous studies have indicated a potential correlation between COPD, lipid metabolism, and dietary inflammation. However, the exact mechanisms by which dietary inflammation regulates the pathological processes of COPD related to lipid metabolism remain unclear. NHHR is a novel composite index of atherosclerotic lipid profiles, while the Dietary Inflammatory Index (DII) measures diet-induced inflammation. This study explores the relationship between NHHR and COPD and evaluates whether DII mediates this association. We employed multivariable logistic regression, smooth curve fitting, threshold effect analysis, and subgroup analysis to explore the relationship between NHHR and the incidence of COPD. Additionally, we conducted a mediation analysis to explore the potential relationship between dietary inflammatory index (DII) levels and the relationship between NHHR and COPD. This analysis encompassed 13,452 participants, with 2,332 reporting incidents of COPD. Following adjustment for all covariates using multivariable logistic regression, each unit increase in NHHR level and DII level was associated with a 10% (OR = 1.10, 95% CI: 1.05, 1.16) and 8% (OR = 1.08, 95% CI: 1.04, 1.13) increase, respectively, in the incidence rate of COPD. Furthermore, compared to the lowest quartile, the highest quartile of NHHR level and DII level was associated with a 47% (p < 0.001) and 50% (p < 0.001) increase, respectively, in the incidence rate of COPD. Smooth curve fitting and threshold effect analysis revealed a nonlinear relationship between NHHR and the risk of COPD, with a breakpoint at 2.60. Mediation analysis indicated that DII mediated 7.24% of the association between NHHR and COPD (p = 0.004). Higher NHHR levels are associated with an increased prevalence of COPD. Moreover, this association is mediated by DII, suggesting that an anti-inflammatory diet may be beneficial.

Predicting Ozone Concentration in Hangzhou with the Fusion Class Stacking Algorithm

Aiming at the problem that the single machine learning model has low prediction accuracy of daily average ozone concentration, an ozone concentration prediction method based on the fusion class Stacking algorithm （FSOP） was proposed, which combined the statistical method ordinary least squares （OLS） with machine learning algorithms and improved the prediction accuracy of the ozone concentration prediction model by integrating the advantages of different learners. Based on the principle of the Stacking algorithm, the observation data of the daily maximum 8h ozone average concentration and meteorological reanalysis data in Hangzhou from January 2017 to December 2022 were used. Firstly, the specific ozone concentration prediction models based on the light gradient boosting machine （LightGBM） algorithm, long short-term memory model （LSTM）, and Informer model were established, respectively. Then, the prediction results of the above models were used as meta-features, and the OLS algorithm was used to obtain the prediction expression of ozone concentration to fit the observed ozone concentration. The results showed that the prediction accuracy of the model combined with the class Stacking algorithm was improved, and the fitting effect of ozone concentration was better. Among them, R2, RMSE, and MAE were 0.84, 19.65 μg·m-3, and 15.50 μg·m-3, respectively, which improved the prediction accuracy by approximately 8% compared with that of the single machine learning model.

Recognition and Characterization of Nanoscale Phases: Modulus Mapping of Asphalt Film in Pavement Mixture Cores.

The objective of this study is to recognize and characterize the nanoscale phase modulus mapping of the asphalt film in pavement mixture cores using atomic force microscopy quantitative nanomechanical technology. The pavement core samples from the upper and middle layers of four highways and laboratory samples were taken as the research object. The phase modulus-macro property correlation of recovered asphalt was analyzed using mathematical statistics. The results showed that the pavement core samples had more significant multi-phase and diversified phase characteristics compared to lab samples. This indicated that the asphalt in the pavement core had an obvious phase separation phenomenon due to aging. The phase modulus of each sample was distributed across a relatively wide numerical range, and there were also many numerical points with large fluctuations. Especially for the mixture sample containing SBS (Styrene-Butadiene-Styrene)-modified asphalt, the phase modulus distribution mappings presented a multi-peak phenomenon. Hence, considering the distribution characteristics of the data, the box plot method was introduced. Compared with quantified results from laboratory samples, the phase modulus of SBS-modified asphalt increased by 0.96 times, 1.18 times and 1.15 times, and that of base asphalt increased by 0.59 times, 0.56 times, 0.42 times, 1.24 times and 0.39 times, respectively. This indicates that the aging degree of asphalt in the upper layer was generally greater than that of the asphalt in the middle layer and that there was an aging gradient in the direction of pavement depth. All points were within the 95% confidence band in terms of correlation fitting, indicating a better fitting effect between phase modulus and complex shear modulus, as well as between phase modulus and penetration. This research provides innovative ideas for future multi-scale numerical simulation and cross-scale performance model development of asphalt binders.

Effects of Perceived Fit and Authenticity in Transgender Influencer Endorsement: An Analysis of the Bud Light and Dylan Mulvaney’s Partnership

ABSTRACT Influencer endorsements are a popular way for companies to promote their brands, products, and services. While extant literature has identified influencer fit and authenticity as key factors influencing source credibility and in turn, endorsement effectiveness, there is little research making a bridge between perceived fit and perceived authenticity, especially in the context of transgender influencer endorsement. A major U.S. beer brand, Bud Light, was recently under fire for endorsing influencer Dylan Mulvaney amidst growing tensions between social acceptance of gender diverse populations and continuous anti-transgender legislation in the U.S. and Europe. Using an online survey with 687 U.S. adult participants, this study examined how consumer perceptions of fit and authenticity impacted outcomes of Bud Light’s transgender influencer endorsement in the framework of the match-up hypothesis. Findings suggest that perceived authenticity mediates the relationships between perceived fit and consumer responses and the match-up effects of influencer fit are moderated by attitude toward transgender people.

Association between neutrophil-to-high-density lipoprotein cholesterol ratio and metabolic dysfunction-associated steatotic liver disease and liver fibrosis in the US population: a nationally representative cross-sectional study using NHANES data from 2017 to 2020

BackgroundThe neutrophil-to-high-density lipoprotein cholesterol ratio (NHR) has emerged as a promising biomarker for assessing inflammation and lipid dysregulation. Increasing evidence indicates that these metabolic disturbances play a crucial role in the development of metabolic dysfunction-associated steatotic liver disease(MASLD). This study aims to investigate the association between NHR, MASLD, and liver fibrosis.MethodsThis cross-sectional study analyzed data from the 2017–2020 National Health and Nutrition Examination Survey (NHANES). Weighted multivariate logistic regression models were used to investigate the association between NHR and both MASLD and liver fibrosis. Smoothed curve fitting and threshold effect analysis were performed to detect potential nonlinear relationships. Subgroup analyses were conducted to assess the consistency of these associations across different groups.ResultsThe study involved 4,761 participants. We observed a significant positive association between NHR and MASLD (OR = 1.20, 95% CI: 1.09–1.31). However, there was no significant association between NHR and liver fibrosis (OR = 1.01; 95% CI: 0.94–1.09). The analysis of smoothed curve fitting and threshold effect revealed an inverted U-shaped relationship between NHR and MASLD, with a turning point at 5.63.ConclusionOur findings indicate a positive correlation between elevated NHR levels and MASLD prevalence. However, we did not observe a significant association between NHR and liver fibrosis prevalence. Further prospective research is needed to validate these findings in a longitudinal setting.

Spatial differentiation and influencing factors of effective phosphorus in cultivated soil in the water source area of the mid-route of South-to-North water transfer project.

The long-term application of phosphate fertilizers in agricultural production leads to a large accumulation of phosphorus in the soil. When it exceeds a certain limit, phosphorus will migrate to surrounding water bodies through surface runoff and other mechanisms, potentially causing environmental risks such as eutrophication of water bodies and increasing the risk of water source pollution. This study takes Shiyan City, the water resources area of the mid-route of the South-to-North Diversion Project (MSDP), as the study area. Based on 701 sampling points of topsoil, geostatistics and geodetectors were used to explore the spatial heterogeneity and influencing factors of available phosphorus (AP) in the topsoil of the area. The results show that the effective phosphorus content in the topsoil of the study area ranges from 0.30 to 146.00 mg/kg, with an average value of 14.28 mg/kg, showing strong variability characteristics. Geostatistical analysis shows that among all theoretical models, the exponential model has the best fitting effect, with a lump gold effect of 0.447 and a range of 82,000 m. The soil available phosphorus content shows an increasing trend from the Central Valley lowlands to the surrounding mountainous hills. Among them, elevation is the main controlling factor for the spatial variation of available phosphorus in the topsoil, followed by soil types, planting systems, annual precipitation, and organic matter. The non-linear enhancement or dual-factor enhancement among various environmental factors reveals the diversity and complexity of spatial heterogeneity affecting available phosphorus content in cultivated soil. This study could provide scientific references for maintaining ecological security in the water source area of the MSDP, improving the precise management of AP, and enhancing cultivated land quality.

Ambient music and retailer equity: The moderating role of music fit

Researchers have explored the impact of ambient music on consumer responses in the retail environment and reported conflicting findings. This study investigated the relationship between ambient music and retailer equity, with a focus on the moderating effect of music fit. Data were collected through a field study conducted in a fashion store, where pop songs were used to attract customers (N = 406). Hierarchical regression analysis results suggested that ambient music was positively associated with retailer equity, and the strength of this relationship was moderated by music fit. Specifically, the positive impact of ambient music on retailer equity was stronger when the music aligned with customers' overall image of the store. The theoretical and practical implications of the findings are discussed.

Faithful pals and familiar locales: differentiating social and spatial site fidelity during reproduction.

Site fidelity-the tendency to reuse familiar spaces-is expected to improve fitness. Familiarity with the local environment is particularly crucial when resource demands or predation risk are high. Consequently, site fidelity often peaks during reproduction when energetic costs are high and offspring are vulnerable. For many species, the environment they experience is not solely a function of geography but also of the social environment. Social fidelity, the selection for familiar social environments, could constitute an independent or parallel strategy to spatial fidelity when considering behaviour at the spatial-social interface. Using global positioning system locations from caribou across Newfoundland, we tested whether females selected calving sites based on proximity to familiar conspecifics, in addition to geographical (spatial) fidelity. These strategies were synergistic, not alternative, and correlated across the population but more variable within individuals. We also tested whether either form of fidelity affected reproductive success. We failed to detect an effect of spatial or social fidelity on reproductive success in this population. Nevertheless, given the association between social and spatial fidelity and the demonstrated fitness consequences of site fidelity in other systems, familiar conspecifics and the potential benefits these social partners provide may be an underappreciated component driving site fidelity.This article is part of the theme issue 'The spatial-social interface: a theoretical and empirical integration'.

Energy landscapes of peptide-MHC binding.

Molecules of the Major Histocompatibility Complex (MHC) present short protein fragments on the cell surface, an important step in T cell immune recognition. MHC-I molecules process peptides from intracellular proteins; MHC-II molecules act in antigen-presenting cells and present peptides derived from extracellular proteins. Here we show that the sequence-dependent energy landscapes of MHC-peptide binding encode class-specific nonlinearities (epistasis). MHC-I has a smooth landscape with global epistasis; the binding energy is a simple deformation of an underlying linear trait. This form of epistasis enhances the discrimination between strong-binding peptides. In contrast, MHC-II has a rugged landscape with idiosyncratic epistasis: binding depends on detailed amino acid combinations at multiple positions of the peptide sequence. The form of epistasis affects the learning of energy landscapes from training data. For MHC-I, a low-complexity problem, we derive a simple matrix model of binding energies that outperforms current models trained by machine learning. For MHC-II, higher complexity prevents learning by simple regression methods. Epistasis also affects the energy and fitness effects of mutations in antigen-derived peptides (epitopes). In MHC-I, large-effect mutations occur predominantly in anchor positions of strong-binding epitopes. In MHC-II, large effects depend on the background epitope sequence but are broadly distributed over the epitope, generating a bigger target for escape mutations due to loss of presentation. Together, our analysis shows how an energy landscape of protein-protein binding constrains the target of escape mutations from T cell immunity, linking the complexity of the molecular interactions to the dynamics of adaptive immune response.

Population size rescaling significantly biases outcomes of forward-in-time population genetic simulations.

Simulations are an essential tool in all areas of population genetic research, used in tasks such as the validation of theoretical analysis and the study of complex evolutionary models. Forward-in-time simulations are especially flexible, allowing for various types of natural selection, complex genetic architectures, and non-Wright-Fisher dynamics. However, their intense computational requirements can be prohibitive to simulating large populations and genomes. A popular method to alleviate this burden is to scale down the population size by some scaling factor while scaling up the mutation rate, selection coefficients, and recombination rate by the same factor. However, this rescaling approach may in some cases bias simulation results. To investigate the manner and degree to which rescaling impacts simulation outcomes, we carried out simulations with different demographic histories and distributions of fitness effects using several values of the rescaling factor, , and compared the deviation of key outcomes (fixation times, allele frequencies, linkage disequilibrium, and the fraction of mutations that fix during the simulation) between the scaled and unscaled simulations. Our results indicate that scaling introduces substantial biases to each of these measured outcomes, even at small values of . Moreover, the nature of these effects depends on the evolutionary model and scaling factor being examined. While increasing the scaling factor tends to increase the observed biases, this relationship is not always straightforward, thus it may be difficult to know the impact of scaling on simulation outcomes a priori. However, it appears that for most models, only a small number of replicates was needed to accurately quantify the bias produced by rescaling for a given . In summary, while rescaling forward-in-time simulations may be necessary in many cases, researchers should be aware of the rescaling procedure's impact on simulation outcomes and consider investigating its magnitude in smaller scale simulations of the desired model(s) before selecting an appropriate value of .

Correlation study between structural parameters of droplets and rheological properties of O/W high internal phase Pickering emulsions above the closest packing density

The correlation between the structural parameters of droplets and rheological properties of O/W high internal phase Pickering emulsions (HIPPEs) stabilized by soy protein isolate (SPI) nanoparticles was elucidated, with a volume fraction of dispersed phase (ϕ) above the closest packing density (74%). The structural basis of SPI nanoparticles was confirmed to be spherical heat-induced protein aggregates, which had moderate wettability and excellent interfacial activity. The structural parameters of emulsion droplets (contact length L, diameter D, length d1, width d2, the number of adjacent contact droplets Z), and the stability and rheological properties of HIPPEs were characterized by the confocal laser scanning microscopy (CLSM), diffusing wave spectroscopy (DWS), and mechanical rheometer respectively. The results of CLSM indicated the transition of droplets from spherical to polyhedral shapes as increased ϕ, accompanied by an increased L and Z. The rheological and stability analysis confirmed the widened linear viscoelastic range, elevated gel point (εc), and the extended half−life of the intensity autocorrelation function of HIPPEs as ϕ increased. Moreover, the loss factor (tan δ) remained constant at 0.1 within the ϕ of 74%–86%, revealing the solid−like nature of HIPPEs. The correlation between ϕ, structural parameters of droplets, and rheological properties of HIPPEs was further analyzed. The nonlinear regression fitting between the L/D and G' (elastic modulus) yielded a better fitting effect than d1/d2 and Z, suggesting an intrinsic correlation between emulsion structure and rheology. In summary, this study elucidated the intricate relationship between ϕ, droplet structure, and rheological properties of HIPPEs, offering a research foundation and theoretical basis for the development and application of protein particle−stabilized HIPPEs.

Revisiting ant-plant-pollinator interactions: plant fitness depends on mutualist identity

Abstract Two species may share a mutualistic interaction if the benefits gained by the interaction outweigh the costs incurred. In this study, we tested experimentally how the identity of ants (pinned) and floral visitors of an extrafloral nectary (EFN)-bearing plant can affect plant fitness. We quantified ant activity and floral visitor visitation overlap over time, floral visitor behaviour, amount of floral resources collected, and plant fitness as influenced by the ant species identity in an EFN-bearing plant from Brazilian Cerrado savanna, Qualea multiflora (Vochysiaceae). We found that: (i) ant activity and floral visitation overlap greatly in time; (ii) floral visitors vary in their response to the presence of ants; (iii) different ant species have different impacts on floral visitors; (iv) ants affected the amount of floral resources collected by pollinators, but their levels were contingent on ant identity; and (v) plant fitness components (fruit production, seed weight, and seed size) were most strongly affected by the largest and most aggressive ant species. Our results suggest that the balance of the trade-off between the beneficial effects of ant protection against herbivorous insects and the negative consequences for plant fitness by deterring pollinators depends on the species identity of both the ants and the floral visitors to the plant.

Synthetic directed evolution for targeted engineering of plant traits.

Improving crop traits requires genetic diversity, which allows breeders to select advantageous alleles of key genes. In species or loci that lack sufficient genetic diversity, synthetic directed evolution (SDE) can supplement natural variation, thus expanding the possibilities for trait engineering. In this review, we explore recent advances and applications of SDE for crop improvement, highlighting potential targets (coding sequences and cis-regulatory elements) and computational tools to enhance crop resilience and performance across diverse environments. Recent advancements in SDE approaches have streamlined the generation of variants and the selection processes; by leveraging these advanced technologies and principles, we can minimize concerns about host fitness and unintended effects, thus opening promising avenues for effectively enhancing crop traits.

Strategic Alignment, Performance, and the Moderating Effect of Regulatory Fit

ABSTRACT We examine how the alignment of performance measurement and strategy affects performance on a multidimensional task. Our experiment varies both the strategy (speed versus accuracy) of the hypothetical firm for which participants work and the individual performance measure that is reported to them, creating two conditions of clear alignment and two of clear misalignment. We find that although workers are responsive to the performance measure regardless of its alignment, they are also sensitive to the strategy such that costly alignment effects are observed. We also predict and find that workers respond asymmetrically to misalignment in accuracy performance but not in speed performance, demonstrating that the effects of misaligned performance measurement depend on the fit between firm strategy and the nature of the task being performed. Data Availability: Data are available from the authors upon request. JEL Classifications: M40; M41; M50.

Effects of cardiorespiratory fitness on changes in secretory immunoglobulin A following a maximal exercise test

Effects of cardiorespiratory fitness on changes in secretory immunoglobulin A following a maximal exercise test

The association between ‘weekend warrior’, regular exercise, and cognitive function in elderly individuals with and without depressive symptoms: A cross-sectional analysis from NHANES 2011–2014

BackgroundWhile previous studies have suggested that both ‘Weekend Warrior’ (WW) and Regular Exercise (RE) patterns confer health benefits, the relationship between different types of physical activity (PA) and cognitive function (CF) in elderly individuals with and without depressive symptoms remains unclear. MethodsOur study leveraged the NHANES 2011–2014 dataset, focusing on older adults. We explore the relationship between PA and CF, stratifying by depressive status. Our statistical approach included multivariable regression analysis to identify relationships between PA levels and cognitive outcomes, along with advanced techniques such as smoothed curve fitting and threshold effect analysis to examine potential nonlinear associations and identify optimal PA pattern for cognitive health. ResultsAnalysis revealed a positive correlation between PA time and CF across all participants (β-depressive symptoms = 0.03, 95 % CI: 0.01–0.05; β-non-depressive symptoms = 0.01, 95%CI: 0.00–0.02). When comparing against the inactive, non-depressed participants partaking in WW showed improved cognitive scores (β-WW = 0.22, 95 % CI: 0.05–0.39), similar to those engaging in RE (β-RE = 0.15, 95 % CI: 0.09–0.21). However, among the depressed participants, significant cognitive improvements were observed in the RE (β-RE = 0.15, 95 % CI: 0.04–0.25), with the WW showing less definitive results (β-WW = 0.22, 95 % CI: −0.02-0.47). LimitationThe cross-sectional nature limits causal inferences. ConclusionOur findings affirm the potential role of PA in enhancing CF among older subjects without depressive symptoms. However, only RE was associated with improved CF in those with depressive symptoms. These results are critical for crafting personalized PA guidelines to enhance cognitive health in the aging population.