Interactive Effects Of Age Research Articles

The relationship between sleeptime and depression among middle-aged and elderly Chinese participant during COVID-19 epidemic and non-epidemic phases.

The global impact of the COVID-19 pandemic had significantly altered the daily routines of people worldwide. This study aimed to compare how sleeptime and depression among Chinese residents had differed between periods during and outside the epidemic. Furthermore, it delved into the interactive effect of age in this relationship. Utilizing data from the China Health and Retirement Longitudinal Study (CHARLS) study in 2015 and the recently released data from 2020, which covered the pandemic period. Depression was assessed using Center for Epidemiologic Studies Depression Scale (CESD-10), considering a score of 10 or higher as indicative of depression. Participants were categorized based on age, specifically those aged 60 years and older. multivariate logistic regression and interaction analyses were employed to assess the interplay of age, supported by subgroup and sensitivity analyses to reinforce our findings. The 2020 database comprised 19,331 participants, while the 2015 database had 10,507 participants. Our findings demonstrated a significant correlation between sleeptime and depression in both unadjusted models and models adjusted for all variables in both datasets (p<0.001). Upon stratifying by age and adjusting for relevant factors, we identified an interaction effect among age, sleeptime, and depression (p=0.004 for the interaction in the 2020 database, compared to 0.004 in 2015). The restricted cubic spline analysis in both datasets showcased a nonlinear relationship between sleeptime and depression. During both epidemic and non-epidemic periods in China, there existed a correlation between sleep duration and depression, which interacts with age.

Cross-sectional, comparative study of health-related quality of life across the adult lifespan in multiple sclerosis

Purpose This study examines the independent and interactive effects of age and multiple sclerosis (MS) on health-related quality of life (HRQOL). Materials and methods The sample included persons with MS (n = 207) and healthy controls (HCs; n = 99) divided into three age groups (young, middle-aged, and older adults) who completed a battery of questionnaires, including the 36-item Short-Form Health Survey (SF-36) as a measure of HRQOL. The SF-36 yielded scores for the Physical Component Summary (PCS) (i.e. physical HRQOL) and Mental Component Summary (MCS) (i.e. mental HRQOL). The data were analyzed using two-way MANOVA. Results There was no interaction between age and disease status on HRQOL, but there were significant main effects of age and disease status on HRQOL. HRQOL was significantly lower in participants with MS than HCs, regardless of age. Physical HRQOL was lower, whereas mental HRQOL was higher across age groups. Conclusion The findings suggest that future research should develop behavioral and rehabilitation approaches that are applicable for improving HRQOL across the lifespan in persons with MS, particularly for physical HRQOL in older adults with MS.

Can training programmes change behaviour? Age, creative behaviour, and active learning

ABSTRACT Earlier studies provide mixed results regarding the influence of training programme on behavioural change. We draw on the transfer of training theory to explain behavioural change of 45 early childhood teachers, refugees living in the Dzaleka Refugee camp in Malawi, who attended a training programme. Our results indicate that age, creative behaviour, and their interactive effect have a positive influence on behavioural change. Interestingly, active learning by itself had no significant influence on behavioural change. When considering the interactive effect of age and active learning, we found a positive influence on behavioural change.

The Interactive Effect of Age and Education on Bonding Social Capital towards Empowerment of Urban Agriculture Communities in Klang Valley, Malaysia

The Interactive Effect of Age and Education on Bonding Social Capital towards Empowerment of Urban Agriculture Communities in Klang Valley, Malaysia

Handgrip strength and upper limb functional performance measures in people over 18 years old: Analysis of relationships and influencing factors

BackgroundHandgrip strength is a common, simple, and inexpensive method to measure muscle strength. On the other hand, the functional performance measurement involves a usual task which implies repeating elements between the individuals’ interaction and the environment. This is fundamental for projecting their results to daily life situation. PurposeTo explore the relationship between grip strength and measures of functional performance of the upper limbs (ULs) in people over 18 years of age, and to determine the influence of sociodemographic and anthropometric variables on the relationship. Study DesignA cross-sectional study was conducted under the analytical empirical approach, using linear associations between handgrip strength and functional performance measurement tests (correspondence analysis). MethodsThree hundred sixty-two male and female individuals between 18 and 91 years of age from 4 Colombian cities participated. The grip strength of both ULs measured with a digital dynamometry was associated with the Box and Block Test (BBT, manual dexterity), Nine-Hole Peg Test (NHPT, daily living tasks), and Jebsen-Taylor Hand Function Test (JJT, ability to grasp, pick up, and place). Multiple linear regression analyzes were performed to assess possible explanatory factors of a sociodemographic and anthropometric order. ResultsA significant association was found between the grip strength of dominant and non-dominant ULs with all functional performance tests (ρ > 0.27 and p < .001), except for the writing and simulated feeding subtests of the JJT (ρ ≤ 0.16). An interactive effect of age was found in the relationship between grip strength and the 3 functional performance tests. ConclusionsThese results support the association between grip strength with the NHPT, JJT, and BBT measures and the interactive effect of age on the performance of all tests.

Effect of trehalose on miR-132 and SIRT1 in the hippocampus of aged rats

Aging causes substantial molecular to morphological changes in the brain. The brain cells are more susceptible towards oxidative damage due to impaired antioxidant defense system. Sirtuin1 (SIRT1) is a crucial cellular survival protein, which its gene has been identified as a direct target of microRNA 132 (miR-132). Trehalose contributes to preventing neuronal damage through several mechanisms. However, little is known about the interactive effects of aging and trehalose on the expression pattern of miR-132 and SIRT1 in the hippocampus. Male Wistar rats were divided into four groups. Two groups of aged (24 months) and young (4 months) rats were administered 2% trehalose solution for 30 days. Two other groups of aged and young rats received regular tap water. At the end of treatment, the levels of Sirt1 mRNA and its protein, malondialdehyde, protein carbonyl content, total antioxidant capacity, tumor necrosis factor α (TNF-α), as well as the expression of miR-132 were measured in the hippocampus. We found that trehalose treatment upregulated the expression of SIRT1 and miR-132. Moreover, administration of trehalose enhanced the level of total antioxidant activity whereas reduced the levels of lipid peroxidation, protein carbonyl content, and TNF-α. In conclusion, our data indicated that trehalose restored antioxidant status and alleviated inflammation in the hippocampus which was probably associated with the upregulation of SIRT1 and miR-132.

Sex-specific impact of aging on muscle sympathetic neural discharge patterns during incremental rhythmic handgrip exercise

Sex-disparities exist in the risk of developing hypertension throughout the lifespan, with a greater prevalence of hypertension amongst postmenopausal females compared to similarly aged males. Though the underlying mechanisms are multifactorial, exaggerated sympathetic neuro-cardiovascular reactivity may be an important contributor. Indeed, postmenopausal females exhibit exaggerated exercise pressor responses compared to young adults, and older males. However, the interactive effects of age and sex on muscle sympathetic nerve activity (MSNA) and action potential (AP) coding patterns during exercise remains unclear. We hypothesized that older females would exhibit the greatest increase in MSNA and AP recruitment during exercise and post-exercise circulatory occlusion (PECO) relative to young males and females, as well as older males. MSNA and AP discharge patterns (microneurography and continuous wavelet transform) were assessed in 12 young males (YM (mean±SD); 26±4, years), 11 young females (YF; 25±4 years), 11 older males (OM; 71±11 years), and 12 older females (OF; 71±4 years) during incremental rhythmic handgrip exercise to fatigue followed by 2 minutes of PECO. At peak exercise, OM demonstrated a smaller change from baseline (Δ) in MSNA burst incidence (BI) compared to all other groups (YM: Δ8±9, YF: Δ9±8, OM: Δ-6±8, OF: Δ6±7 bursts/100heartbeats; all ANOVA post-hoc P&lt;0.05), whereas ΔMSNA burst frequency (BF), Δburst amplitude (BA), and Δtotal activity were not different between groups (all P&gt;0.05). Conversely, YM demonstrated greater ΔAPs/burst (YM: Δ5±3, OM: Δ0.4±3, OF: Δ2±2 APs/burst; post-hoc P&lt;0.05) and ΔAP clusters/burst (YM: Δ2±1, OM: Δ0.1±1, OF: Δ0.7±0.7 Clusters/burst; post-hoc P&lt;0.05) compared to OM and OF, but not compared to YF (Δ2±3 APs/burst and Δ0.9±0.8 clusters/burst; both P≥0.07). However, no group differences were observed in the recruitment of larger axons (YM: Δ6±2, YF: Δ4±2, OM: Δ2±5, OF: Δ4±3 clusters; P=0.33). Contrary to exercise, group-by-time interactions existed during PECO for ΔMSNA BF ( P&lt;0.01), ΔBI ( P&lt;0.01), and Δtotal activity ( P&lt;0.01) where greater increases occurred during the first minute of PECO in young compared to older adults (all post-hoc P&lt;0.05), whereas in the final minute of PECO, MSNA ΔBF and ΔBI were only greater in YM compared to OM and OF (all P&lt;0.05), and total activity was greater in YM and YF compared to OF only (all P&lt;0.05). No group-by-time interactions were observed for ΔMSNA BA ( P=0.37), ΔAPs/burst ( P=0.94), ΔAP clusters/burst ( P=0.95) or Δtotal AP clusters ( P=0.41) during PECO. Altogether, MSNA and AP reactivity during exercise was not exaggerated in OF, but age-related reductions in AP recruitment were observed in males. During PECO, MSNA responses were lower in older relative to young adults but, AP recruitment was unaltered by age. Thus, exaggerated MSNA or AP reactivity may not explain the greater prevalence of hypertension in OF. Supported by the Natural Sciences and Engineering Council of Canada, and IEEM Indirect Funds. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Age, but not an immune challenge, triggers terminal investment in the Pacific field cricket, Teleogryllus oceanicus.

The terminal investment hypothesis proposes that, when individuals are faced with a threat to survival, they will increase investment in current reproduction. The level of the threat necessary to elicit terminal investment (the dynamic terminal investment threshold) may vary based on other factors that also influence future reproduction. Here, we tested whether there is an interactive effect of age and an immune challenge on the dynamic terminal investment threshold in the Pacific field cricket, Teleogryllus oceanicus. We measured the courtship call, mating attractiveness, ejaculate size, and offspring production of T. oceanicus males. We found only limited support for the dynamic terminal investment threshold: there was no consistent evidence of a positive interaction between male age and immune challenge intensity. However, we found evidence for age-related terminal investment: older males produced a larger spermatophore than younger males. Older males also had a slower calling rate compared to younger males, suggesting a potential trade-off between these two pre- and post-copulatory traits. As some, but not all, reproductive traits responded plastically to cues for terminal investment, our research highlights the importance of considering a broad range of pre-and post-copulatory traits when exploring the potential for terminal investment to occur.

Neutrophil-to-Lymphocyte Ratio Amplifies the Effects of Aging on Decrements in Grip Strength and Its Functional Neural Underpinnings.

The neutrophil-to-lymphocyte ratio (NLR) is a trans-prognostic biomarker of physiologic stress and inflammation linked to muscle weakness in older adults. Generation of grip force coincides with sustained activity in the primary sensorimotor cortex (SM1). The current study investigates whether whole-brain functional connectivity, that is, degree centrality (CD) of SM1 relates to grip strength and whether both functional measures are predicted by advancing age as a function of the NLR. Astructural regression model investigated the main and interactive effects of age and NLR on grip strength and CD of SM1 in 589 adults aged 21-85years (M=45.87, SD=18.06). The model including the entire sample had a good fit (χ 2(4)=1.63, p=.804). In individuals aged 50years and older, age predicted lower grip strength and SM1 CD as a function of increasing NLR. In a model stratified by sex, the effect of age, NLR, and their interaction on grip strength are significant for older men but not older women. Analyses support CD of SM1 at rest as a neural biomarker of grip strength. Grip and its neural underpinnings decrease with advancing age and increasing NLR in mid to late life. Age-related decrements in grip strength and functional connectivity of brain regions involved in the generation of dynamic grip appear to be accelerated as a function of systemic physiological stress and inflammation, particularly in older men.

The association between air pollutants and hospitalizations for asthma: an evidence from Chengdu, China.

Exposure to air pollutants has been linked to the exacerbation of asthma, and it has become a risk to human welfare and health throughout the globe. Previous works did not achieve a systematic study by considering interactive effects of age, gender, and meteorological factors on the exposure-effect relationship between air pollutants and asthma. We aimed to quantitatively investigate the effects of air pollutants on hospitalizations for asthma in Chengdu, China. This is a retrospective and population-based study. Data of asthma hospitalization records for residents, the average daily concentrations of air pollutants including SO2, CO, NO2, O3, PM10, and PM2.5, and meteorological variables from 1 January 2014 to 31 December 2014 in Chengdu, China, were obtained from several government departments. A generalized additive model (GAM) was used to analyze the exposure-effect relationship between air pollutants and daily asthma hospitalizations after controlling the long-time seasonal trend, "day-of-week (DOW)" effect, holiday effect, and confounding meteorological factors. A total of 7,503 hospitalizations were assessed. Significant associations between hospitalizations and air pollutants were found. The relative risk (RR) for hospitalizations for every 10 µg/m3 increase in PM2.5 and PM10 for the male group were 1.0121 [95% confidence interval (CI): 1.0012-1.0232] and 1.0075 (95% CI: 1.0001-1.015), respectively. The elderly (≥65 years old) tended to have a higher RR (1.0022; 95% CI: 1.0001-1.0043) for each 10 mg/m3 increase in CO than the other age groups. All pollutants had slightly protective effects on the younger age group (≤14 years old). O3 had more significant effects in cold season, whereas SO2 impacted more significantly in warm seasons, particularly for females and adults (14-65 years old). Adverse effects of ambient concentrations of air pollutants on hospitalizations for asthma are evident, especially in specific population groups. Male patients were more susceptible to PM2.5 and PM10, and the elderly were more sensitive to CO. The effects of O3 in China were significant in the cold season, whereas SO2 impacted more significantly in the warm season particularly on females and adults. The study would be meaningful for asthma intervention and corresponding healthcare resource management.

Ultrasound evaluation of biometric and Doppler parameters of kidneys in sheep in the prenatal and postnatal periods

The aim of this study was the ultrasound evaluation of kidneys in sheep fetuses during consecutive weeks of pregnancy and of lamb kidneys in the first two weeks after delivery. To evaluate the fetal kidneys, 20 single-pregnancy Suffolk sheep were examined. In the postpartum period, the kidneys were examined in 10 ewe lambs and 9 ram lambs. B-Mode ultrasound was used to assess the length, width and thickness of the kidney, as well as the thickness of the renal parenchyma and the renal cortex. Vascular haemodynamics was assessed with color and pulsed Doppler in renal, segmental and interlobular arteries. Fetal kidneys were visualized from 53 ± 2.00 days, and corticomedullary differentiation was observed from the 10th week of pregnancy onwards. All fetal kidney biometric parameters increased significantly in the following weeks of pregnancy. The width and thickness of the kidneys were greater in male than in female fetuses (P < 0.05). The left kidney was thicker than the right kidney (P < 0.05). An interactive effect of gestational age, fetal sex and kidney location on kidney width, kidney thickness and renal parenchyma thickness (P < 0.05) has been demonstrated. All the biometric parameters of the kidneys differed significantly between the first and the second week of life of the lambs. The thickness of the renal cortex was greater in the ram lambs (P < 0.05). However, the length, width and thickness depended on the location of the kidneys (P < 0.05). An interactive effect of age, sex and kidney location on kidney width in lambs was demonstrated (P < 0.05). In the fetal renal artery, peak systolic velocity (PSV) and end-diastolic velocity (EDV) were significantly lower than in lamb kidneys in the first few days of life. In turn, the PSV/EDV and resistance index (RI) in fetal kidneys were significantly higher than that in newborn lambs. In lambs, PSV, PSV/EDV, RI and PI in the renal artery were significantly higher than that in the segmental and interlobular arteries. Regardless of the location of the arterial vessel, significant differences were noted between the Doppler indices in one-week and two-week-old lambs. The obtained results may be useful in establishing reference values for biometric and hemodynamic ultrasound parameters of sheep kidneys during the fetal and neonatal period. Assessment of the renal cortex is especially of great clinical importance. Increased echogenicity and reduced thickness may indicate certain pathological processes in the kidney. The results of Doppler indices indicate that the postnatal renal haemodynamics depends on the age of the lambs and the location of the renal vessels. Therefore, these factors should be taken into account in the assessment of renal arterial blood flow in lambs.

Trehalose Attenuates Learning and Memory Impairments in Aged Rats via Overexpression of miR-181c.

MicroRNAs have been recognized as important regulators of the aging process. Trehalose, a natural disaccharide, displays protective effects against neuronal impairment through several mechanisms. However, little is known about the interactive effects of aging and trehalose on behavioral function and underlying miRNA expression patterns in the hippocampus of young and old rats. Male Wistar rats were divided into four groups. Two groups of aged (24months) and young (4months) rats were administered 2% trehalose solution for 30days. Two other groups of aged and young rats received regular tap water. At the end of treatment, rats were assessed for cognitive behavior using the Morris water maze test. The expression level of miR-181c and mir-34c was also measured by qRT-PCR. We found that trehalose treatment reduced learning and memory impairment in old rats compared to control old animals (p < 0.05). In contrast, cognitive performance was not significantly improved in trehalose-treated young rats in comparison with young controls (p > 0.05). We also showed that the expression level of miR-181c was significantly increased in trehalose-treated rats (p < 0.01). However, analysis of miR-34c expression level indicated no significant difference between trehalose-treated old rats and non-treated old animals (p > 0.05). Our results indicated that trehalose treatment improved learning and memory function in aged rats by targeting miR-181c. Therefore, trehalose administration may provide a therapeutic strategy to ameliorate age-associated cognitive impairment.

The Risk of Hearing Impairment From Ambient Air Pollution and the Moderating Effect of a Healthy Diet: Findings From the United Kingdom Biobank.

The link between hearing impairment and air pollution has not been established, and the moderating effect of a healthy diet has never been investigated before. The purpose of this study was to investigate the association between air pollution and hearing impairment in British adults aged 37–73 years, and whether the association was modified by a healthy diet. We performed a cross-sectional population-based study with 158,811 participants who provided data from United Kingdom Biobank. A multivariate logistic regression model was used to investigate the link between air pollution and hearing impairment. Subgroup and effect modification analyses were carried out according to healthy diet scores, gender, and age. In the fully adjusted model, we found that exposure to PM10, NOX, and NO2 was associated with hearing impairment [PM10: odds ratio (OR) = 1.15, 95% confidence interval (95% CI) 1.02–1.30, P = 0.023; NOX: OR = 1.02, 95% CI 1.00–1.03, P = 0.040; NO2: OR = 1.03, 95% CI 1.01–1.06, P = 0.044], while PM2.5 and PM2.5 absorbance did not show similar associations. We discovered an interactive effect of age and air pollution on hearing impairment, but a healthy diet did not. The findings suggested that exposure to PM10, NOX and NO2 was linked to hearing impairment in British adults, whereas PM2.5 and PM2.5 absorbance did not show similar associations. These may help researchers focus more on the impact of air pollution on hearing impairment and provide a basis for developing effective prevention strategies.

Independent and Combined Effects of Age and COVID on Patient Outcomes

PurposeTo evaluate the independent effect and interactive effect of age and positive Covid-19 status on patient survival and number of days spent on ECMO.MethodsSingle center data was gathered for patient's currently receiving ECMO treatment. The main effect and interaction effect of patients’ age and COVID status was evaluated to investigate the impact of these factors on patient outcomes of discharged deceased and days on ECMO. A logistic regression model of 204 patients was used to evaluate the outcome of discharged deceased, and a Poisson regression model of 129 patients was used to evaluate the outcome of patient days spent on ECMO.ResultsIn the logistic regression on discharged deceased adjusting for COVID status (n=204), age was associated with higher odds of death (OR=1.05 per year older, CI95 1.03-1.07). COVID was strongly associated with mortality (OR=4.81, CI95 2.46-9.43). Incorporating an interaction between age and COVID status, being discharged deceased was significantly associated with older age but COVID status and the interaction between COVID and age were not significant predictors of mortality. In the Poisson regression on days on ECMO (n=129), main effects of both age and COVID were noted. In the test of the interaction of age by COVID status, the interaction was also significant as were both main effects.ConclusionBoth age and positive COVID status were found to be independent risk factors for increased patient mortality, however only age was associated with increased patient mortality when interaction between age and COVID was incorporated. Conversely, older patients with and without COVID exhibited decreased days on ECMO, whereas COVID was associated with a significant increase in days on ECMO.

Interactive effects of age and inflammation on change in ecologically-assessed cognitive functioning

Inflammation has been implicated as a precursor to steeper declines in age-associated cognitive decline. Here we investigated biomarkers of peripheral inflammation [basal cytokines, stimulated cytokines (ex vivo), C-reactive protein (CRP)] as moderators of age-related changes in cognitive functioning. As part of the Effects of Stress on Cognitive Aging, Physiology, and Emotion (ESCAPE) study, participants (N = 233; 65% female; 63% Black, 25% Hispanic; 25-65 years of age) completed up to four instances of ambulatory cognitive testing per day across two weeks, over three waves of annual assessments. After each 2-week ecological momentary assessment (EMA) burst, blood was collected and assayed for inflammatory biomarkers. Performance on spatial working memory (mean Euclidean distance errors), processing speed (mean symbol search reaction time), and working memory (n-back test accuracy) tasks were averaged across all instances within an EMA burst. CRP and age interactively predicted change in spatial working memory (B = 0.003, [0.000, 0.005], t(133.60) = 2.350, p = 0.020) such that higher CRP at older ages (~60 years) was associated with a loss of the expected practice effects across waves; at younger ages, CRP did not relate to change in spatial working memory. In a similar fashion, basal (B = -0.002, [-0.004, -0.000], t(103.26) = -2.399, p = 0.018) and stimulated cytokine levels (B = -0.002, [-0.004, -0.000], t(126.65) = -2.183, p = 0.031) interacted with age to predict change in processing speed across waves. These results indicate that inflammation may be critically associated with changes in cognitive functioning in older mid-life adults.

Aging with Traumatic Brain Injury: Deleterious Effects of Injury Chronicity Are Most Pronounced in Later Life.

Understanding the effects of age on longitudinal traumatic brain injury (TBI) outcomes requires attention to both chronic and evolving TBI effects and age-related changes in health and function. The present study examines the independent and interactive effects of aging and chronicity on functional outcomes after TBI. We leveraged a well-defined cohort of individuals who sustained a moderate/severe TBI and received acute inpatient rehabilitation at specialized centers with high follow up rate as part of their involvement in the TBI Model Systems longitudinal study. We selected individuals at one of two levels of TBI chronicity (either 2 or 10 years post-injury) and used an exact matching procedure to obtain balanced chronicity groups based on age and other characteristics (N = 1993). We found that both older age and greater injury chronicity were related to greater disability, reduced functional independence, and less community participation. There was a significant age by chronicity interaction, indicating that the adverse effects of greater time post-injury were most pronounced among survivors who were age 75 or older. The inflection point at roughly 75 years of age was corroborated by post hoc analyses, dividing the sample by age at 75 years and examining the interaction between age group and chronicity. These findings point to a need for provision of rehabilitation services in the chronic injury period, particularly for those who are over 75 years old. Future work should investigate the underlying mechanisms of this interaction towards the goal of developing interventions and models of care to promote healthy aging with TBI.

Interactive effects of aging and aerobic capacity on energy metabolism\u2013related metabolites of serum, skeletal muscle, and white adipose tissue

Aerobic capacity is a strong predictor of longevity. With aging, aerobic capacity decreases concomitantly with changes in whole body metabolism leading to increased disease risk. To address the role of aerobic capacity, aging, and their interaction on metabolism, we utilized rat models selectively bred for low and high intrinsic aerobic capacity (LCRs/HCRs) and compared the metabolomics of serum, muscle, and white adipose tissue (WAT) at two time points: Young rats were sacrificed at 9 months of age, and old rats were sacrificed at 21 months of age. Targeted and semi-quantitative metabolomics analysis was performed on the ultra-pressure liquid chromatography tandem mass spectrometry (UPLC-MS) platform. The effects of aerobic capacity, aging, and their interaction were studied via regression analysis. Our results showed that high aerobic capacity is associated with an accumulation of isovalerylcarnitine in muscle and serum at rest, which is likely due to more efficient leucine catabolism in muscle. With aging, several amino acids were downregulated in muscle, indicating more efficient amino acid metabolism, whereas in WAT less efficient amino acid metabolism and decreased mitochondrial β-oxidation were observed. Our results further revealed that high aerobic capacity and aging interactively affect lipid metabolism in muscle and WAT, possibly combating unfavorable aging-related changes in whole body metabolism. Our results highlight the significant role of WAT metabolism for healthy aging.

Reproductive performance in houbara bustard is affected by the combined effects of age, inbreeding and number of generations in captivity

Although captive breeding programs are valuable for conservation, they have been shown to be associated with genetic changes, such as adaptation to captivity or inbreeding. In addition, reproductive performance is strongly age-dependent in most animal species. These mechanisms that potentially impact reproduction have often been studied separately, while their interactions have rarely been addressed. In this study, using a large dataset of nine male and female reproductive parameters measured for 12,295 captive houbara bustards (Chlamydotis undulata undulata) over 24 years, we investigated the relative and interactive effects of age, inbreeding and number of generations in captivity on reproduction. We clearly identified (1) senescence patterns in all parameters studied; (2) negative effects of inbreeding on sperm characteristics, display behavior, egg weight, egg volume and hatching probability; and (3) changes in phenotypic values for seven parameters according to number of generations in captivity. However, the effect sizes associated with age were substantially greater than those associated with inbreeding and number of generations in captivity. Beyond the independent effects of these three factors on reproductive parameters, the results highlighted their interactive effects and thus the importance of integrating them in the design of genetic management plans for conservation breeding programs.

Life stage, lifespan, and life course perspectives on vocational behavior and development: A theoretical framework, review, and research agenda

This article for the 50th anniversary issue of the Journal of Vocational Behavior theoretically integrates, reviews, and critically discusses research that investigates vocational behavior and development based on life stage, lifespan, and life course perspectives. First, we describe key tenets of these perspectives and associated theories of vocational behavior and development. Second, we present a theoretical framework that integrates the lifespan and life course perspectives by addressing (a) relationships between age and important work and career outcomes (i.e., career decisions and success, job search and turnover, work motivation and behavior, attitudes, occupational health and well-being), (b) age-related person and contextual mechanisms of these relationships, and (c) interactive effects of age with person characteristics, contextual characteristics, and/or work and career outcomes. Third, based on the theoretical framework, we summarize cumulative empirical evidence for these age-related associations and effects for the various work and career outcomes. Moreover, we review conceptual and empirical articles on aging, life stage, lifespan, and life course development published in the Journal of Vocational Behavior over the past 50 years. Finally, we conclude with a discussion of theoretical implications and directions for future research that adopts an integrated lifespan and life course perspective on vocational behavior and development.

Dating and sexualities across the life course: The interactive effects of aging and gender

Research on aging and sexuality has proliferated in recent years. However, little is known about the gender-specific effects of aging on dating and sexuality. Using survey data from the 2014 wave of Singles in America (SIA), a comprehensive survey on adult singles' experiences with dating and sexuality, we examine whether age differentially affects heterosexual women's and men's dating and sexual attitudes and behaviors and whether gender differences persist across the life course. We find that men remain active in the dating and sexual marketplace longer than women. Although main effects of gender differences are documented in dating and sexual attitudes and behaviors, the results show that gender does not operate the same across the life course. Notably, gender differences shrink or are eliminated in attitudes and behaviors surrounding partnering in midlife and late adulthood, suggesting that age is integral to understanding gendered heterosexuality.