Allostatic load and biological anthropology

The impact of forced awakening on morning blood pressure surge

BACKGROUND

Poor sleep quality can cause an increase in morning blood pressure surge (MBPS), an independent risk factor of cardiovascular disease (CVD) events. Awakening induced by external factors such as alarm clocks, may also contribute to increased MBPS.

OBJECTIVES

To (1) compare the MBPS and sleep quality parameters between natural and forced awakenings and (2) examine the potential impact of forced awakening on MBPS, independent of sleep quality.

METHODS

Thirty-two healthy adults participated in this pilot study, which included one night of natural awakening and one night of forced awakening (i.e., sleep was interrupted by an alarm after five hours). Objective and self-reported sleep quality parameters were measured using a multisensory wristband and sleep diaries, respectively, and beat-to-beat blood pressure variability was assessed using a continuous blood pressure monitor. Analyses included a paired t-test (objective 1) and linear mixed models (objective 2).

RESULTS

Participants predominantly consisted of young, healthy, and highly educated Asian adults. During the night of sleep with forced awakening, significantly higher MBPS, lower objective wakefulness after sleep onset, and lower self-reported sleep latency were observed, compared to the night with natural awakening. Forced awakening was significantly associated with increased MBPS after controlling for age, sex, mean arterial pressure, and sleep quality.

CONCLUSIONS

Forced awakening may significantly increase MBPS, consequently heightening the risk of CVD events. Study findings should be validated in a larger sample. Further research is also warranted to examine the impact of forced awakening on MBPS in individuals with CVD.

Association between allostatic load and depression in patients with sleep disorders: Evidence from the National Health and Nutrition Examination Survey (NHANES)

OBJECTIVE

Allostatic load (AL) is an indicator of the cumulative wear and tear on the body's physiological systems that can predict onset of a range of health problems. However, the relationship between AL and depression in patients with sleep disorders is unclear. This study explored the association between AL and depression in patients with sleep disorders.

METHODS

Using data from the 2015-2016 National Health and Nutrition Examination Survey, a total of 4618 adults aged 18 years and older in the United States were included in this cross-sectional analysis. AL was calculated using nine biological markers, with a score of ≥3 indicating a high level. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with a score of ≥10 indicating risk for depression. Logistic regression models were employed to analyze the relationship between AL and depression.

RESULTS

Among the 1309 participants diagnosed with sleep disorders, 212 (16.2%) were identified as being at risk for depression on the PHQ-9. A total of 55.2% (n = 117) of depressed persons had high AL levels. In the unadjusted model, AL levels were associated with depression in those with sleep disorders (OR=1.53, 95% CI = 1.14-2.05, p < 0.01). This relationship remained significant in the adjusted model (OR=1.52, 95% CI=1.11-2.10, p < 0.05), after controlling for potential confounders.

CONCLUSION

High AL levels in patients with sleep disorders were positively associated with depression, indicating that elevated AL may increase the risk of depression in this population, or alternatively, depression may increase the risk of AL.

Sleep and blood pressure variability: A systematic literature review

BACKGROUND

Blood pressure variability (BPV) is a prognostic marker of cardiovascular disease (CVD). Sleep is recognized as a significant risk factor for CVD; however, little is known about the relationship between sleep characteristics and BPV.

OBJECTIVE

In this systematic review, we aimed to (1) describe methods used to measure BPV and sleep and (2) describe the current evidence in the literature on the association between sleep and BPV.

METHODS

A systematic search was conducted using the search terms "sleep" AND ("blood pressure variability" OR "ambulatory blood pressure monitor") in CINAHL, PubMed, Web of Science, and PsycINFO databases.

RESULTS

Twenty-two studies were included in this systematic review. Sleep was measured using various methods, including polysomnography, actigraphy, sleep diaries, and questionnaires, while BPV was measured over various time intervals using different monitoring devices such as a beat-to-beat blood pressure (BP) monitoring device, a 24-h ambulatory BP monitor, or an automatic upper arm BP monitor. The studies demonstrated mixed results on the associations between sleep parameters (sleep quality, architecture, and duration) and increased BPV.

CONCLUSIONS

Although the mechanisms that explain the relationship between sleep and BPV are still unclear, accumulating evidence suggests potential associations between increased BPV with poor sleep quality and longer sleep duration. Given the recent development of sleep and BP monitoring technologies, further research is warranted to assess sleep and BPV under free-living conditions. Such studies will advance our understanding of complex interactions between sleep and CVD risk.

Hidden in plain text: Uncovering hidden heterogeneity and social stratification in Ireland AD 1150-1800

OBJECTIVES

Between the Irish late medieval (AD 1150-c.1550) (LMP) and post-medieval (AD c.1550-1800) (PMP) periods, colonial practices changed land ownership. Contextualizing these periods within a biocultural political economy framework supports increasing social inequality in the PMP, which we expect to be reflected in different skeletal markers of longevity and stress. Therefore, we hypothesized that widespread exposure to stressors and resource deprivation contributed to lower longevity in the PMP compared to the LMP, and that there would be greater variation between sites in the frequency of linear enamel hypoplasias (LEH) in the PMP.

MATERIALS AND METHODS

We estimated age and counted matched pairs of LEH on 526 adult skeletons from the Irish counties of Dublin, Kildare, Louth, and Meath. Age-at-death was compared through Kaplan-Meier survival functions and non-parametric tests. Linear enamel hypoplasias prevalences were analyzed with Mann-Whitney U tests and Generalized Linear Models.

RESULTS

Age-at-death distribution changed between the LMP and PMP for males, with males experiencing an increase in median-age-at-death. The same was untrue for females, who show no changes in median age-at-death. Analysis of LEH frequency per individual showed that variation between sites was significant in the post-medieval period but not in the late medieval period.

CONCLUSION

These results suggest that social organization contributed to embodied health experiences that varied across time periods. Specifically, populations from the PMP appear to have embodied greater social inequality in their more varied susceptibility to stress. Our work demonstrates the strength of pairing historical texts with the analysis of skeletal remains to evaluate the impact of social structures on biological frailty.

Energetic Costs of Stress in Developing Fishes: Quantifying Allostasis and Allostatic Load

Stress exerts negative effects on fish health through stimulation of the hypothalamic-pituitary-interrenal axis and autonomic nervous system, resulting in heightened neural and neuroendocrine responses. Energetic investment and physiological adaptation are then required to re-establish homeostatic stability or reach a new allostatic state. The cost of the energetic investment is referred to as allostatic load (AL). While determining the sources of stress and assessing their consequences have resulted in estimates of AL, most of this work has been conducted in adult mammals and humans; no ALs exist for developing fish. From a series of experiments on a model species, zebrafish (Danio rerio), whose yolk-sac larvae were exposed to two chronic stressors (high-temperature and hypoxia), ALs were quantified based on biomarkers of ontogenetic changes in growth, morphometrics, and metabolic activities. Results showed that for zebrafish yolk-sac larvae, chronic stress imposed high AL and, thus, high total allostatic energetic costs, (Rt (AL)), because of prolonged energy demand in the face of limited resources (e.g., yolk). Under severe chronic stress, energetic costs were sufficiently large that energy-limited developing fish may not be able to fully compensate, resulting in maladaptive responses from allostatic overload, leading either to death or to novel allostatic states, possibly more resilient to environmental change.

Cumulative adversity and survival in the wild

Protecting populations contending with co-occurring stressors requires a better understanding of how multiple early-life stressors affect the fitness of natural systems. However, the complexity of such research has limited its advancement and prevented us from answering new questions. In human studies, cumulative risk models predict adult health risk based on early adversity exposure. We apply a similar framework in wild yellow-bellied marmots (Marmota flaviventer). We tested cumulative adversity indices (CAIs) across different adversity types and time windows. All CAIs were associated with decreased pup survival and were well supported. Moderate and acute, but not standardized CAIs were associated with decreased lifespan, supporting the cumulative stress hypothesis and the endurance of early adversity. Multivariate models showed that differences in lifespan were driven by weaning date, precipitation, and maternal loss, but they performed poorly compared with CAI models. We highlight the development, utility, and insights of CAI approaches for ecology and conservation.

Psychological distress, forced awakening, and morning blood pressure surge

BACKGROUND

Morning blood pressure surge (MBPS) has been recognized as an independent predictor of cardiovascular disease events. Psychological distress, including anxiety, depression, and perceived stress, and behavioral risk factors, such as poor sleep quality, have been associated with increased MBPS. Elevations in sympathetic activity induced by forced awakening may also contribute to further increases in MBPS. Yet, no examination of the interrelationships among psychological distress, sleep quality, awakening mode (natural vs. forced awakenings), and MBPS has been undertaken.

OBJECTIVE

This pilot study aimed: (1) to examine if MBPS differs by awakening mode and (2) to investigate whether psychological distress is associated with MBPS difference between natural and forced awakenings, independent of sleep quality.

METHODS

Thirty-two healthy adults were included in this cross-sectional study. Blood pressure was measured using a beat-to-beat blood pressure monitor over two nights, consisting of one night of natural awakening and one night of forced awakening. Psychological distress and sleep quality were assessed using questionnaires. We conducted paired t-tests (aim 1) and multiple linear regressions (aim 2).

RESULTS

MBPS was significantly greater during forced awakening compared with natural awakening. In addition, the MBPS difference between natural and forced awakenings was significantly greater in participants with higher anxiety levels, independent of sleep quality.

CONCLUSION

We found that augmentation of MBPS by forced awakening was significantly greater in individuals who reported higher anxiety levels. Additional research is needed to examine the potential impacts of forced awakening and anxiety on MBPS in a larger sample of individuals at risk for cardiovascular disease.

Association of Combined PFOA, PFOS, Metals and Allostatic Load on Hepatic Disease Risk

This study utilizes the National Health and Nutrition Examination Survey (NHANES) 2017-2018 data to explore the relationship between exposure to perfluoroalkyl substances (specifically perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), metals lead (Pb), mercury (Hg), and cadmium (Cd), allostatic load, and hepatic disease markers, including the fatty liver index a measure of the likelihood of non-alcoholic fatty liver disease, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin. The paper identified significant associations and interaction effects by employing descriptive statistics, Spearman's correlation analysis, linear regression, and Bayesian kernel machine regression (BKMR). Descriptive statistics highlight sex-specific differences in contaminant levels. Spearman's analysis underscores strong correlations among metals and per- and polyfluoroalkyl substances (PFAS). Linear regression reveals significant impacts of specific contaminants on AST, ALT, ALP, and bilirubin levels, adjusting for age and alcohol consumption. BKMR results further elucidate the complex, potentially synergistic relationships between these environmental exposures and the likelihood of non-alcoholic fatty liver disease, offering nuanced insights into their combined effects on liver health. The findings emphasize the intricate dynamics of environmental exposures on hepatic function, advocating for targeted public health interventions.

Allostatic load and frailty do not covary significantly among older residents of Greater Poland

BACKGROUND

Physiological dysregulation/allostatic load and the geriatric syndrome frailty increase with age. As a neurophysiological response system, allostasis supports survival by limiting stressor-related damage. Frailty reflects decreased strength, endurance, and physical abilities secondary to losses of muscle and bone with age. One suggestion, based on large cohort studies of person's ages 70 + years, is that frailty contributes to allostatic load at older ages. However, small community-based research has not confirmed this specific association.

METHODS

To further explore possible associations between allostatic load and frailty, we enrolled 211 residents of Greater Poland aged 55-91 years living in a small village (Nekla, N = 104) and an urban center and capital of Greater Poland (Poznan, N = 107). For each, we recorded age, self-reported sex, and residence and estimated a 10-biomarker allostatic load score (ALS) and an 8-biomarker frailty index. We anticipated the following: higher ALS and frailty among men and rural residents; for frailty but not ALS to be higher at older ages; significant associations of ALS with sex and place of residence, but not with age or frailty. The significance of observed associations was evaluated by t-tests and multivariate regression.

RESULTS

ALS did not vary significantly between men and women nor between Nekla and Poznan residents overall. However, women showed significantly higher frailty than men. Nekla men showed significantly higher ALS but not frailty, while Nekla women showed nonsignificantly higher ALS and lower frailty than Poznan. In multivariate analyses, neither age, nor sex, nor residence was associated with ALS. Conversely, age, sex, and residence, but not ALS, are associated significantly with frailty. In Nekla, both age and sex, but in Poznan only age, are associated with ALS. Among women, both age and residence, but among men, neither associated with ALS. In no case did ALS associate significantly with frailty.

CONCLUSION

In this sample, lifestyle factors associated with residence, age, and sex influence stress-related physiology, less so in women, while ALS and frailty do not covary, suggesting their underlying promoters are distinct. Similar complex associations of physiological dysregulation with frailty, age, sex, and residence likely exist within many local settings. Knowledge of this variation likely will aid in supporting health and healthcare services among seniors.

Weight stigma and allostatic load in adults: protocol for a scoping review

INTRODUCTION

Weight-related stigma (WS) has been associated with adverse psychosocial and physical health effects. Despite the relationship between WS and allostatic load, there are no integrative reviews of this association. This scoping review aims to provide a comprehensive overview of the relationship between allostatic load biomarkers associated with WS by identifying gaps in this topic and proposing recommendations for future research.

METHODS AND ANALYSIS

This protocol was guided by the methodological framework of Arksey and O'Malley and the Joanna Briggs Institute (JBI). The research questions were based on the population-concept-context framework. Studies in adults diagnosed as overweight or obese, exposed to WS and assessing the association between WS and biomarkers of allostatic load will be included. A search will be conducted in Medline (Ovid), PsycINFO (Ovid), Scopus (Elsevier), Cochrane Library (Wiley) and Google Scholar. The search strategy will be conducted in three stages, based on the JBI recommendation with the MESH terms "Social Stigma," "Weight Prejudice," "Biomarkers," "Allostasis," "Adults" and related terms. Data extraction will be done with a template adapted from JBI. The search strategy and selection process results will be presented in a flow chart and summarised in the text. The main results will be presented in a descriptive synthesis.

ETHICS AND DISSEMINATION

Ethics review and approval are not required. The results will be disseminated through peer-reviewed publications, conferences, congresses or symposia.

Predictors of milk cortisol in North American women

OBJECTIVES

Human milk content varies across mother-child dyads, environments, and populations. Among the hormones in milk is cortisol, a glucocorticoid; its impact on the breastfeeding child is unknown. Milk cortisol may constitute a signal to the child's developing physiology which can shape characteristics (e.g., growth, temperament) to prevailing environmental conditions. This exploratory study evaluated the maternal, breastfeeding, and infant characteristics associated with milk cortisol.

METHODS

We evaluated archived milk specimens for cortisol using enzyme immunoassay and employed an information-theoretic approach to assess associations between milk cortisol and participant characteristics with linear regression modeling. Because we employed secondary data, information for some variables likely to impact milk cortisol variation (e.g., time of day, socioeconomic status, maternal or infant body mass index, milk energy density) was unavailable.

RESULTS

Participants were 48 lactating mothers from upstate New York, aged 21-40 years. Milk cortisol ranged from 0.098 to 1.007 μg/dL. Child age ranged from 1 to 26 months. In linear regression employing best fit modeling criteria, milk cortisol increased with child age (B: 0.069; p: .000; a 7.1% increase in milk cortisol for each month of child age), while child symptoms of illness (B: -0.398; p: .057; a 33% decrease) and consumption of complementary foods (B: -.525; p: .020; a 41% decrease) were associated with lower milk cortisol.

CONCLUSIONS

We speculate that increasing milk cortisol with child age plays a role in signaling development (e.g., as increasing independence increases risk for injury and other negative health outcomes), independent of the maternal stressors we could capture.

Berry Consumption in Relation to Allostatic Load in US Adults: The National Health and Nutrition Examination Survey, 2003-2010

INTRODUCTION

Berries are a rich source of antioxidant polyphenols and other nutrients that are associated with good health. Allostatic load (AL) is an aggregate measure of chronic stress-induced physiological dysregulations across cardiovascular, metabolic, autonomic, and immune systems; the extent of these dysregulations, collectively or in each system, can be characterized by a composite score or a domain score assessed by integrated biomarkers. It was hypothesized that the anti-inflammatory and other effects of berries lower AL. The association was determined between berry consumption and AL composite and domain scores in the 2003-2010 National Health and Nutrition Examination Survey (NHANES).

METHODS

Berry intake was measured using two 24 h dietary recalls collected from US adults in the 2003-2010 NHANES (n = 7684). The association with AL and its specific domains was examined using population weight-adjusted multivariable linear regression.

RESULTS

The mean AL composite scores for consumers of any berries (11.9), strawberries (11.6), and blueberries (11.6), respectively, were significantly lower than nonconsumers (12.3), after fully adjusting for sociodemographic, lifestyle, and dietary confounders. A significant dose-response relationship was determined between greater consumption of total berries, strawberries, and blueberries and lower mean AL composite scores (p-trend < 0.05, for all). Consistently, mean cardiovascular and metabolic domain scores remained significantly lower in the consumers of total berries (mean cardiovascular domain score: 4.73 versus 4.97 for nonconsumers; mean metabolic domain score: 2.97 versus 3.1), strawberries (4.73 versus 4.95; 2.99 versus 3.1), and blueberries (4.6 versus 4.95; 2.92 versus 3.11). Berry consumers also had significantly lower mean AL immune scores (1.52 versus 1.56) and lower mean AL autonomic scores (2.49 versus 2.57) than nonconsumers (initial sample: n = 15,620).

CONCLUSIONS

The current study indicates that consumption of berries lowers the AL composite scores and potentially reduces stress-related disease risks in the US adult population.

Application of Allostatic Load Theory in Cancer Management and Treatment Outcomes

Efforts have been made to improve health outcomes management by identifying the factors associated with survival in patients with cancer. However, different social, nutritional, and management modalities and personal and clinical characteristics may lead to various mortalities and morbidities among patients with cancer. Although stress is known to influence health and well-being in humans, there is still a gap in the studies on how stress plays a significant role in clinical outcomes in patients with cancer. Allostatic load, accumulated physiologic damage because of stressors, differs on the basis of individual perception of stress, coping skills, and other factors. This theory depicts how stress affects and predicts long-term outcomes such as morbidity and mortality. The main goal of this study is to provide potential benefits of using this theory in the cancer field to identify stressors and develop personalized interventions. This study will describe allostatic load theory and explain the relationships between potential stressors and the outcomes through the various levels of dysregulations in cancer. In addition, this study will provide theory implementation in pancreatic cancer.

Associations between childhood maltreatment and physiological dysregulation in adulthood: Methodological decisions and implications

BACKGROUND

Childhood maltreatment is linked with health problems in adulthood. Theoretical models suggest that maltreatment leads to dysregulation in several bodily systems, and this has been corroborated using measures of physiological function (i.e., biomarkers). Methodological decisions involving the measurement of maltreatment and dimension reduction with respect to biomarkers (i.e., combining information across multiple measures) may influence research findings.

OBJECTIVE

The present study compares associations between childhood maltreatment and adult physiological dysregulation using multiple dimension reduction approaches and measures of maltreatment.

PARTICIPANTS AND SETTING

Participants were recruited, as children, to a prospective study of the correlates and consequences of childhood maltreatment. 253 participants were retained and provided biomarker data at midlife. Physiological dysregulation was operationalized with a conventional allostatic load approach and a novel statistical distance approach.

METHODS

Regression models were employed with allostatic load or statistical distance as the outcome and prospectively or retrospectively measured child maltreatment as the primary predictor.

RESULTS

When using allostatic load as the outcome, prospectively measured childhood maltreatment was positively associated with physiological dysregulation (b = 0.70, SE = 0.31, p = 0.02). When using statistical distance as the outcome, retrospectively measured childhood maltreatment was positively associated with physiological dysregulation (b = 0.69, SE = 0.19 p < 0.001).

CONCLUSIONS

We report a positive association between childhood maltreatment and physiological dysregulation at midlife. However, the significance and magnitude of effects varied with different maltreatment and physiological dysregulation measures. Further review of the methods used to study adult health conditions and their relation to childhood maltreatment is needed.

Biological normalcy and body fat: Obesity prevalence, fat stigma, and allostatic load among late adolescents and young adults

OBJECTIVES

Biological normalcy provides a framework to assess tensions between clinical definitions of "normal," statistical norms, and normative beliefs. A prevailing cultural belief is obesity directly causes poor health, but research has demonstrated consequences of fat stigma. Previous research linked fat stigma and allostatic load (AL) in adults, but this has not been demonstrated in youth, and the role of obesity prevalence is unknown. This study assesses the relationship between fat stigma and AL among youth from counties varying by obesity prevalence.

MATERIALS AND METHODS

Undergraduates from 38 counties across the US state of Indiana (n = 175) were recruited. Fat stigma was measured using the brief stigmatizing situations inventory (SSI). AL was calculated using eight biomarkers representing cardiovascular, metabolic, and immune function. Poisson regression assessed relationships of interest and adjusted for potential confounding. An interaction term and stratified analyses were used to assess moderation.

RESULTS

SSI was not statistically associated with obesity prevalence (RR = 0.96, p = 0.173) but did statistically significantly predict AL (RR = 1.019, p = 0.045) when adjusting for confounders. Obesity prevalence moderated the relationship between SSI and AL (RR = 0.993, p = 0.001).

DISCUSSION

Results suggest that fat stigma, regardless of body fat percentage, is associated with physiologic wear and tear on the late adolescent body, and that exposure to obesity during earlier adolescence moderates this relationship. Those most at risk for high AL reported high fat stigma and lived in counties with relatively low obesity prevalence during earlier adolescence, suggesting vulnerability to fat stigma may be heightened where obesity is less common.

Effects of pair housing on behavior, cortisol, and clinical outcomes during quarantine-like procedures for rhesus macaques (Macaca mulatta)

BACKGROUND

Compatible pair housing of macaques in research settings increases species-typical behaviors and facilitates beneficial social buffering. It is not yet established whether these benefits are maintained after intrafacility transfer and domestic quarantine, which are two stressors that can lead to behavioral and clinical abnormalities.

METHODS

We evaluated 40 adolescent male rhesus macaques who were single- or pair-housed immediately following an intrafacility transfer. We measured behavior, fecal cortisol, body weight, and diarrhea occurrence. Body weight and diarrhea occurrence were also retrospectively analyzed in an additional 120 adolescent rhesus who underwent a similar transfer.

RESULTS AND CONCLUSIONS

Pair-housed macaques exhibited less of some undesirable behaviors (e.g., self-clasping) and experienced less diarrhea than single-housed subjects; however, no significant differences in cortisol levels or alopecia measures were found. The demonstrated beneficial effects of pair housing for rhesus macaques following intrafacility transfer and adjustment suggest pairing upon arrival at a new facility will bolster animal welfare.

Comparing Predictors and Outcomes of Higher Allostatic Load across Zoo-Housed African Great Apes

Stressors over the lifespan can contribute to physiological dysregulation, or allostatic load. Allostatic load has been studied in humans using allostatic load indices (ALIs) for over 25 years, but the same methods are rarely applied to other species. We constructed an ALI for zoo-housed western lowland gorillas, chimpanzees, and bonobos and tested potential predictors of and health outcomes associated with allostatic load. Allostatic load scores ranged from 0–6 for gorillas and chimpanzees and 0–7 for bonobos. Age was significantly associated with allostatic load in gorillas and chimpanzees but not bonobos. Cumulative stressful events were positively associated with allostatic load in chimpanzees. Wild-caught gorillas had higher allostatic load than zoo-born conspecifics, but rearing differences between zoo-born animals were not significant for any species. Age may affect associations of allostatic load with stressful events and birthplace as results change when it is included as a covariate. Allostatic load was not retained in best-fit models for risk of all-cause morbidity, cardiac disease, or mortality risk. Some analyses herein were limited by the use of retrospective data, such as reason for sample collection and length of records provided for individual animals. Nevertheless, these data indicate additional research is needed to optimize ALIs for non-human primates.

Weathering within war: Somatic health complaints among Vietnamese older adults exposed to bombing and violence as adolescents in the American war

OBJECTIVE

People living in war may experience deteriorating health via weathering (wear and tear) from long-term exposures to psychosocial and environmental stressors. Weathering embodied in somatic health complaints may illuminate the effects of war on health.

METHODS

We investigate whether wartime stress exposures occurring during adolescence and early adulthood affect weathering in late adulthood via linear regression with data from the Vietnamese Health and Aging Study (VHAS). VHAS is a cross-sectional study wherein investigators surveyed 2447 adults aged 60+ in four districts of northern and central Vietnam in 2018. These same individuals ranged in age from seven to 52 in 1965, with most having been in adolescence or early adulthood at the peak of the American war in Vietnam (1965-1975). The sample used for this study (n = 2254) were participants in the first VHAS wave in 2018.

RESULTS

We find older Vietnamese adults exposed to higher-intensity provincial bombing suffer more numerous somatic health complaints (unstandardized β = 0.005, SE = 0.001, p = 0.001). Additionally, greater health complaints emerge among older adults whose most intense bombing exposures were at younger ages of adolescence (< age 15) as compared to those whose peak exposures were in older ages (19-25) (unstandardized β = 0.62 95%, SE = 0.19, p = 0.01).

CONCLUSION

Our findings suggest that age of exposure to armed conflict is a critical determinant of weathering across the life course.

Aging, frailty, and design of built environments

Before developing agriculture, herding or metallurgy, humans occupied most of the world. Multiple socioculturally-based responses supported their migration, including building shelters and constructing niches to limit environmental stressors. Sheltered settings provided social support and security during stressful times, along with opportunities for injured, aging, and frail members to survive. Modern built environments are designed for similar purposes, to support human growth, development, reproduction, and maintenance. However, extended survival in modern settings has costs. With age, muscle (sarcopenia) and bone loss (osteopenia, osteoporosis), along with somatic, physiological, and sensory dysfunction, reduce our physical capabilities, increase our frailty, and impede our abilities to interface with built and natural environments and manufactured artifacts. Thereby, increasing our dependence on built environments to maintain autonomy and quality of life.

What follows is a conceptual review of how frailty may limit seniors within modern built environments. It suggests age-related frailty among seniors provides specific data for those designing environments for accessibility to all users. It is based in human ecological theory, and physiological and gerontological research showing senescent alterations, including losses of muscle, bone, and sensory perceptions, produce a frail phenotype with increasing age limiting our mobility, activity, use of space, and physical abilities. As an individual phenotype, frailty leads to age-related physical and performance declines. As a physiological assessment, frailty indices amalgamate individual measures of functional abilities into a single score. Such frailty indices increase with age and differ betwixt individuals and across groups. To design built environments that improve access, usability, and safety for aging and frail citizens, today’s seniors provide living samples and evidence for determining their future abilities, limitations, and design needs. Designing built environments to accommodate and improve the quality of human-environment interactions for frail seniors will improve usability and accessibility for most user groups.

The Role of Social Support in Coping with Psychological Trauma: An Integrated Biopsychosocial Model for Posttraumatic Stress Recovery

This theoretical review proposes an integrated biopsychosocial model for stress recovery, highlighting the interconnectedness of intra- and interpersonal coping processes. The proposed model is conceptually derived from prior research examining interpersonal dynamics in the context of stressor-related disorders, and it highlights interconnections between relational partner dynamics, perceived self-efficacy, self-discovery, and biological stress responsivity during posttraumatic recovery. Intra- and interpersonal processes are discussed in the context of pre-, peri-, and post-trauma stress vulnerability as ongoing transactions occurring within the individual and between the individual and their environment. The importance of adopting an integrated model for future traumatic stress research is discussed. Potential applications of the model to behavioral interventions are also reviewed, noting the need for more detailed assessments of relational dynamics and therapeutic change mechanisms to determine how relational partners can most effectively contribute to stress recovery.

Applying minimally invasive biomarkers of chronic stress across complex ecological contexts

Chronic stress is both theoretically and methodologically challenging to operationalize through biomarkers. Yet minimally invasive, field-friendly biomarkers of chronic stress are valuable in research linking biology and culture, seeking to understand differential patterns of human development across ecological contexts, and exploring the evolution of human sociality. For human biologists, a central question in measurement and interpretation of biomarkers is how stress-responsive physiological systems are regulated across diverse human ecologies. This article aims to describe a conditional toolkit for human biologists interested in the study of chronic stress, highlighting a mix of longstanding and novel biomarkers, with special focus on hair/fingernail cortisol, latent herpesvirus antibodies, allostatic load indices, and serial/ambulatory data collection approaches. Future trends in chronic stress biomarker research, including epigenetic approaches, are briefly considered. This overview considers: (1) challenges in separating a distinctly psychosocial dimension of chronic stress from adversity more broadly; (2) essential characteristics of human ecology that shape interpretation; (3) retrospective vs. longitudinal sampling; (4) the role of age, developmental effects, and local biologies; (5) different timescales of chronicity; and (6) the role of culture.

Cost of resilience: Childhood poverty, mental health, and chronic physiological stress

Childhood poverty is associated with elevated internalizing symptoms. Nevertheless, some children exposed to poverty evince remarkable resilience, demonstrating lower than expected levels of psychological distress. However, recent work suggests that coping with adversity can lead to undesirable physical health consequences. Specifically, successful adaptation in the context of early adversity, including socioeconomic disadvantage, appears to be associated with elevated chronic physiological stress and ill health. The current study adds to this emerging literature by examining in a longitudinal context whether low levels of internalizing symptoms in the face of childhood poverty is accompanied by elevated chronic physiological stress (allostatic load) during childhood, as well as over time from childhood to adulthood. Results (n = 341; M=9.2 years, 49 % female; 94 % Caucasian) show that childhood poverty was prospectively associated with higher allostatic load during adolescence, controlling for baseline allostatic load. Furthermore, greater duration of childhood poverty led to steeper, more elevated allostatic load trajectories from childhood to adulthood, for youth with lower levels of internalizing symptoms. Efforts to manage adverse sequelae of early adversity likely yield a complex array of benefits and costs.

Higher allostatic load in work-related burnout: The Regensburg Burnout Project

BACKGROUND

Burnout and chronic work stress have been linked to various negative health outcomes. While the mechanisms underlying this interplay are still unclear, the allostatic load (AL) model was suggested to demonstrate a possible biological pathway. However, previous studies provided divergent results regarding the association between burnout and AL, probably also due to the heterogeneity of selected samples. Therefore, the aim of the present study was to examine differences in AL between a conceptually strictly specified group of individuals suffering from burnout (BO group) and a healthy comparison group (HC group).

METHODS

After a multi-stage recruitment procedure with strict inclusion criteria based on burnout symptomatology and pathogenesis, the BO group (n = 56) was compared to the HC group (n = 65) regarding an index of AL. The AL-index included 14 parameters: high-sensitivity c-reactive protein (hsCRP), tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), fibrinogen, d-dimer, plasminogen activator inhibitor 1 (PAI-1), glycosylated hemoglobin (HbA1c), high-density lipoprotein (HDL) cholesterol, total cholesterol to HDL cholesterol ratio (TC/HDL), dehydroepiandrosterone-sulphate (DHEA-S), systolic blood pressure (SBP), diastolic blood pressure (DBP), waist-hip ratio (WHR), and body fat percentage.

RESULTS

The BO group showed significantly higher AL-scores in comparison to the HC group. This effect remained significant after adjusting for sex, age, and smoking status. Additionally, burnout symptoms (assessed with the Maslach Burnout Inventory; MBI), MBI-subscales emotional exhaustion and depersonalization as well as chronic work stress (assessed with the effort-reward imbalance questionnaire) were significantly associated with higher AL-scores.

CONCLUSIONS

Consistent with our hypothesis, we detected higher AL-scores in the BO compared to the HC group, indicating a greater cumulative physiological burden in individuals suffering from burnout. Given the high heterogeneity in individuals experiencing burnout symptoms, future studies may focus on well-specified subgroups, when examining the association between burnout and psychophysiological dysregulations.

The application of allostasis and allostatic load in animal species: A scoping review

Principles of allostasis and allostatic load have been widely applied in human research to assess the impacts of chronic stress on physiological dysregulation. Over the last few decades, researchers have also applied these concepts to non-human animals. However, there is a lack of uniformity in how the concept of allostasis is described and assessed in animals. The objectives of this review were to: 1) describe the extent to which the concepts of allostasis and allostatic load are applied theoretically to animals, with a focus on which taxa and species are represented; 2) identify when direct assessments of allostasis or allostatic load are made, which species and contexts are represented, what biomarkers are used, and if an allostatic load index was constructed; and 3) detect gaps in the literature and identify areas for future research. A search was conducted using CABI, PubMed, Agricola, and BIOSIS databases, in addition to a complementary hand-search of 14 peer-reviewed journals. Search results were screened, and articles that included non-human animals, as well as the terms “allostasis” or “allostatic” in the full text, were included. A total of 572 articles met the inclusion criteria (108 reviews and 464 peer-reviewed original research). Species were represented across all taxa. A subset of 63 publications made direct assessments of allostatic load. Glucocorticoids were the most commonly used biomarker, and were the only biomarker measured in 25 publications. Only six of 63 publications (9.5%) constructed an allostatic load index, which is the preferred methodology in human research. Although concepts of allostasis and allostatic load are being applied broadly across animal species, most publications use single biomarkers that are more likely indicative of short-term rather than chronic stress. Researchers are encouraged to adopt methodologies used in human research, including the construction of species-specific allostatic load indexes.

Twenty-first century bioarchaeology: Taking stock and moving forward

This article presents outcomes from a Workshop entitled "Bioarchaeology: Taking Stock and Moving Forward," which was held at Arizona State University (ASU) on March 6-8, 2020. Funded by the National Science Foundation (NSF), the School of Human Evolution and Social Change (ASU), and the Center for Bioarchaeological Research (CBR, ASU), the Workshop's overall goal was to explore reasons why research proposals submitted by bioarchaeologists, both graduate students and established scholars, fared disproportionately poorly within recent NSF Anthropology Program competitions and to offer advice for increasing success. Therefore, this Workshop comprised 43 international scholars and four advanced graduate students with a history of successful grant acquisition, primarily from the United States. Ultimately, we focused on two related aims: (1) best practices for improving research designs and training and (2) evaluating topics of contemporary significance that reverberate through history and beyond as promising trajectories for bioarchaeological research. Among the former were contextual grounding, research question/hypothesis generation, statistical procedures appropriate for small samples and mixed qualitative/quantitative data, the salience of Bayesian methods, and training program content. Topical foci included ethics, social inequality, identity (including intersectionality), climate change, migration, violence, epidemic disease, adaptability/plasticity, the osteological paradox, and the developmental origins of health and disease. Given the profound changes required globally to address decolonization in the 21st century, this concern also entered many formal and informal discussions.

Increased allostatic load associated with ambient air pollution acting as a stressor: Cross-sectional evidence from the China multi-ethnic cohort study

BACKGROUND

Allostatic load measures the cumulative biological burden imposed by chronic stressors. Emerging experimental evidence supports that air pollution acting as a stressor activates the neuroendocrine system and then produces multi-organ effects, leading to allostatic load. However, relevant epidemiological evidence is limited.

OBJECTIVES

We aim to explore the relationships between chronic exposure to ambient air pollution (PM₁, PM_2.5, PM₁₀, and O₃) and allostatic load in Chinese adults.

METHODS

This cross-sectional study included 85,545 participants aged 30-79 from the baseline data of the China Multi-Ethnic Cohort (CMEC). Ambient air pollution levels were evaluated by a satellite-based random forest approach. The previous three-year average exposure concentrations were calculated for each participant based on the residential address. The outcome allostatic load was identified through the sum of the sex-specific scores of twelve biomarkers belonging to four major categories: cardiovascular, metabolic, anthropometric, and inflammatory parameters. We performed statistical analysis using a doubly robust approach which relies on inverse probability weighting and outcome model to adjust for confounding.

RESULTS

Long-term exposure to ambient air pollution was significantly associated with an increased risk of allostatic load, with relative risk (95% confidence interval) of 1.040 (1.024, 1.057), 1.029 (1. 018, 1. 039), and 1.087 (1.074, 1.101) for each 10 μg/m³ increase in ambient PM_2.5, PM₁₀, and O₃, respectively. No significant relationship was observed between chronic exposure to PM₁ and allostatic load. The associations between air pollution and allostatic load are modified by some intrinsic factors and non-chemical stressors. The people with older, minority, lower education, and lower-income levels had a significantly higher allostatic load induced by air pollution.

CONCLUSIONS

Chronic exposure to ambient PM_2.5, PM₁₀, and O₃ may increase the allostatic load. This finding provides epidemiological evidence that air pollution may be a chronic stressor, leading to widespread physiological burdens.

Psychological and biological resilience modulates the effects of stress on epigenetic aging

Our society is experiencing more stress than ever before, leading to both negative psychiatric and physical outcomes. Chronic stress is linked to negative long-term health consequences, raising the possibility that stress is related to accelerated aging. In this study, we examine whether resilience factors affect stress-associated biological age acceleration. Recently developed "epigenetic clocks" such as GrimAge have shown utility in predicting biological age and mortality. Here, we assessed the impact of cumulative stress, stress physiology, and resilience on accelerated aging in a community sample (N = 444). Cumulative stress was associated with accelerated GrimAge (P = 0.0388) and stress-related physiologic measures of adrenal sensitivity (Cortisol/ACTH ratio) and insulin resistance (HOMA). After controlling for demographic and behavioral factors, HOMA correlated with accelerated GrimAge (P = 0.0186). Remarkably, psychological resilience factors of emotion regulation and self-control moderated these relationships. Emotion regulation moderated the association between stress and aging (P = 8.82e-4) such that with worse emotion regulation, there was greater stress-related age acceleration, while stronger emotion regulation prevented any significant effect of stress on GrimAge. Self-control moderated the relationship between stress and insulin resistance (P = 0.00732), with high self-control blunting this relationship. In the final model, in those with poor emotion regulation, cumulative stress continued to predict additional GrimAge Acceleration even while accounting for demographic, physiologic, and behavioral covariates. These results demonstrate that cumulative stress is associated with epigenetic aging in a healthy population, and these associations are modified by biobehavioral resilience factors.

Sulfur mustard and biological ageing: A multisystem biological health score approach as an extension of the allostatic load in Sardasht chemical veterans

BACKGROUND

Mustard gas as a chemical weapon has been used in wars and its long-term side effects are substantial in the human body. This study was aimed to apply an extension of allostatic load, known as synthetic biological health score (BHS), including the wear-and-tear of four physiological systems (endocrine, inflammatory, cardiovascular and metabolic systems) and two organs (liver and kidney) to estimate biological aging caused by sulfur mustard (SM) gas poisoning.

METHODS

The plasma samples were prepared from two following groups of people; 1) 446 individuals exposed to SM gas in 1987. 2) 115 healthy members, at the same range of age and residence, as the non-exposed group. These people were chosen from the same patients' families and have not had any exposure to SM or pulmonary dysfunction. To estimate BHS, 18 blood-derived biomarkers of the mentioned systems and organs were measured and the relative contribution of many social and body parameters across the age groups was explored.

RESULTS

It was revealed, in BHS calculation, the cardiovascular system had the most effect. Also, in the SM group, BHS was significantly higher than in the control group. This feature has a positive correlation with physical parameter (BMI) and a negative correlation with social parameters (salary and educational levels).

CONCLUSION

The multisystem BHS could be useful in the evaluation of biological aging due to SM exposure. Social (education, good-paying job) and physical (BMI) parameters could influence BHS and the higher BHS indicates the progress of biological aging due to mustard gas.

Clinical Measures of Allostatic Load in Children and Adolescents with Food Allergy, Depression, or Anxiety

PURPOSE

Sustained high stress exposure results in chronic activation of the stress response system, dysregulated stress responses, high allostatic load, and poor later-life health. Children and adolescents with chronic health conditions face stressors related to their condition in addition to those typical of childhood and adolescence, placing them at risk of high allostatic load. The purpose of this secondary analysis was to examine whether youth with chronic health conditions differ from controls on clinical measures of allostatic load.

DESIGN AND METHODS

A secondary analysis of two datasets, the electronic health record of a tertiary children's hospital and data from the Survey of the Health of Wisconsin, compared youth with chronic health conditions to controls on clinical measures of allostatic load. Additional analyses explored whether parental stress and mental health influenced these relationships.

RESULTS

Analyses identified differences in BMI, blood pressure, and waist circumference between youth with food allergy, anxiety, or depression, and controls. These relationships differed for males and females and for those with comorbid mental and physical conditions, and were influenced by parent stress and mental health.

CONCLUSIONS

Results support future studies exploring whether high stress in youth with chronic health conditions leads to increased allostatic load. Incorporating biomarkers as well as genetic and epigenetic factors will provide critical insights.

PRACTICE IMPLICATIONS

Youth with mental and physical CHCs may be at increased risk of high allostatic load, reflected in clinical measures of metabolism, and should have regular assessments of their metabolic health.

Allostatic Load and Its Impact on Health: A Systematic Review

INTRODUCTION

Allostatic load refers to the cumulative burden of chronic stress and life events. It involves the interaction of different physiological systems at varying degrees of activity. When environmental challenges exceed the individual ability to cope, then allostatic overload ensues. Allostatic load is identified by the use of biomarkers and clinical criteria.

OBJECTIVE

To summarize the current knowledge on allostatic load and overload and its clinical implications based on a systematic review of the literature.

METHODS

PubMed, PsycINFO, Web of Science, and the Cochrane Library were searched from inception to December 2019. A manual search of the literature was also performed, and reference lists of the retrieved articles were examined.We considered only studies in which allostatic load or overload were adequately described and assessed in either clinical or non-clinical adult populations.

RESULTS

A total of 267 original investigations were included. They encompassed general population studies, as well as clinical studies on consequences of allostatic load/overload on both physical and mental health across a variety of settings.

CONCLUSIONS

The findings indicate that allostatic load and overload are associated with poorer health outcomes. Assessment of allostatic load provides support to the understanding of psychosocial determinants of health and lifestyle medicine. An integrated approach that includes both biological markers and clinimetric criteria is recommended.

Assessing Allostatic Load in Ring-Tailed Lemurs (Lemur catta)

Responses to stress are unavoidable, adaptive mechanisms in humans and non-human animals. However, in humans, chronic stress has been linked to poor health outcomes and early mortality. Allostatic load, the physiologic dysregulation that occurs when an organism is exposed to chronic stressors, has been used to assess stress in humans; less work has been done using non-human primates. Our aim was to determine the relationship between allostatic load in ring-tailed lemurs (Lemur catta) under human care and potentially stressful individual, social, medical and husbandry factors, as well a sex and age. An allostatic load index (ALI) was calculated for 38 lemurs using six biomarkers measured in serum (albumin, cortisol, dehydroepiandrosterone-sulfate, DNA damage, glucose and prostaglandin E2). Potentially stressful factors were recorded over the lifetime of each lemur using medical and husbandry records. Animals with a higher percentage of time spent indoors, those kept in smaller average group sizes, and those with fewer minor group composition changes had, or tended to have, higher ALI. There was no relationship between ALI and sex or age. Some social and husbandry factors were associated with allostatic load in lemurs, indicating that this index may be a useful tool in assessing and determining factors contributing to stress of lemurs and other animals under human care.

Maternal stress effects on infant development in wild Verreaux's sifaka (Propithecus verreauxi)

Abstract

Maternal effects mediated by nutrients or specific endocrine states of the mother can affect infant development. Specifically, pre- and postnatal maternal stress associated with elevated glucocorticoid (GC) output is known to influence the phenotype of the offspring, including their physical and behavioral development. These developmental processes, however, remain relatively poorly studied in wild vertebrates, including primates with their relatively slow life histories. Here, we investigated the effects of maternal stress, assessed by fecal glucocorticoid output, on infant development in wild Verreaux’s sifakas (Propithecus verreauxi), a group-living Malagasy primate. In a first step, we investigated factors predicting maternal fecal glucocorticoid metabolite (fGCM) concentrations, how they impact infants’ physical and behavioral development during the first 6 months of postnatal life as well as early survival during the first 1.5 years of postnatal life. We collected fecal samples of mothers for hormone assays and behavioral data of 12 infants from two birth cohorts, for which we also assessed growth rates. Maternal fGCM concentrations were higher during the late prenatal but lower during the postnatal period compared to the early/mid prenatal period and were higher during periods of low rainfall. Infants of mothers with higher prenatal fGCM concentrations exhibited faster growth rates and were more explorative in terms of independent foraging and play. Infants of mothers with high pre- and postnatal fGCM concentrations were carried less and spent more time in nipple contact. Time mothers spent carrying infants predicted infant survival: infants that were more carried had lower survival, suggesting that they were likely in poorer condition and had to be cared for longer. Thus, the physical and behavioral development of these young primates were impacted by variation in maternal fGCM concentrations during the first 6 months of their lives, presumably as an adaptive response to living in a highly seasonal, but unpredictable environment.

Significance statement

The early development of infants can be impacted by variation in maternal condition. These maternal effects can be mediated by maternal stress (glucocorticoid hormones) and are known to have downstream consequences for behavior, physiology, survival, and reproductive success well into adulthood. However, the direction of the effects of maternal physiological GC output on offspring development is highly variable, even within the same species. We contribute comparative data on maternal stress effects on infant development in a Critically Endangered primate from Madagascar. We describe variation in maternal glucocorticoid output as a function of ecological and reproductive factors and show that patterns of infant growth, behavioral development, and early survival are predicted by maternal glucocorticoids. Our study demonstrates how mothers can influence offspring fitness in response to challenging environmental conditions.

Individual measures of social support may have limited impact on physiological parameters among elderly Kuwaitis

OBJECTIVES

Social support can buffer physiological stress responses, reducing morbidity and mortality risk, but research has occurred primarily in western populations. We examined whether social support was associated with physiological biomarkers in a non-western sample.

METHODS

We predicted evidence of increased physiological dysregulation in those with less social support among elderly Kuwaitis (≥60 years, n = 253). Measures of social support included marital status (married/unmarried), religiosity (low/high), whether adult children lived at home (yes/no), and perceived social support (low/medium/high). Using linear regression, we tested relationships between each social support measure and 17 biomarkers: cortisol, dehydroepiandrosterone-sulfate (DHEA-S), epinephrine, norepinephrine, systolic blood pressure (SBP), diastolic blood pressure (DBP), waist-hip ratio (WHR), total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), very-low-density lipoprotein (VLDL), TC/HDL, LDL/HDL, glycated hemoglobin (HbA1c), C-reactive protein (CRP), and resting heart rate (RHR). We analyzed two models for each, one with the independent variable only and a second including age, smoking, and education as covariates.

RESULTS

Married participants had lower norepinephrine, but higher TC/HDL and LDL/HDL. Higher religiosity was negatively associated with TC (men only) but higher LDL, TC/HDL, and LDL/HDL. Participants with low self-reported social support had higher DBP and HbA1c than those reporting medium or high levels.

CONCLUSIONS

Relatively few biomarkers associated significantly with individual social support measures in a way that suggests improved health for those with more support. As such, some measures of social support may not be universally beneficial across cultures. Additionally, the high degree of respect for and integration of elders in Kuwait society may collectively buffer against negative effects. Cross-cultural comparisons are critical to better understand how social support influences morbidity and mortality across populations.

Marginal Food Security Predicts Earlier Age at Menarche Among Girls From the 2009-2014 National Health and Nutrition Examination Surveys

STUDY OBJECTIVE

This study analyzed the relationship between household food security and variation in age at menarche, as well as the connections between food insecurity, nutritional status, and allostatic load, among girls aged 12-15 years from the 2009-2014 United States National Health and Nutrition Examination Survey (NHANES).

METHODS

Data analysis included mean comparisons of age at menarche among household food security groups (high, marginal, low, and very low) as well as categorical variables known to associate with age at menarche (ethnicity, poverty status, body mass index [BMI], allostatic load, and milk consumption). χ² Analyses were used to test the associations between household food security and additional categorical variables. Univariate and multivariate regression models were used to test the relationship between variation in age at menarche and household food security, ethnicity, BMI, and allostatic load categories while controlling for age.

RESULTS

Non-Hispanic Black and Hispanic/Mexican American girls had earlier mean ages at menarche, higher mean BMIs, and disproportionately experienced household food insecurity when compared to non-Hispanic White-identifying girls. In the univariate analyses, marginal household food security, Hispanic/Mexican American and Black ethnicities, overweight and obese BMI categories, and marginal-high allostatic load were each associated with lower age at menarche compared to reference categories. These associations were maintained in the multivariate analysis, although only Hispanic/Mexican American ethnicity predicted earlier menarche when compared to that of non-Hispanic White girls.

CONCLUSIONS

Marginal household food security, particularly for girls who identified as non-White, predicted earlier age at menarche independent of nutritional status and allostatic load. At the same time, having more energetic resources (ie, higher BMI) also significantly predicted earlier menarche.

Testing a method to improve predictions of disease and mortality risk in western lowland gorillas (gorilla gorilla gorilla) using allostatic load

Allostatic load is the wear-and-tear organisms accumulate due to senescence and stress; it is measured by combining biomarkers from multiple somatic systems into allostatic load indices (ALIs). Frequently used in human research, ALIs have shown consistent results across samples despite different biomarkers and methods. However, determining optimal models likely is necessary if ALIs are to be feasible research tools in other species. Herein, we build on prior research in western lowland gorillas to explore one potential method for determining which biomarkers may be best for estimating allostatic load. After narrowing down which biomarkers to include using a combination of forward stepwise regression and independent biomarker associations with project variables, we estimated allostatic load using both the traditional one-tailed quartile method as well as a multi-method approach. There was a significant positive association between allostatic load and triglycerides, but not cholesterol, both of which are commonly used as diagnostic markers of poor health. Using binomial generalized linear models, a one-unit increase in allostatic load was associated with increased risk of all-cause morbidity and mortality, but reduced risk of cardiac disease. Although conclusions were similar, compared to our original ALIs, these new ALIs had weaker effect sizes and poorer relative goodness of fit, suggesting this method for identifying the best possible list of biomarkers to include in an index was not effective. This report continues the development of ALIs as a clinical tool in wildlife while systematically testing one possible method for determining an optimal ALI for a particular species.

Associations between APOE-, COMT Val108/158Met- and BDNF Val66Met polymorphisms and variations in depressive and anxiety symptoms, sense of coherence and vital exhaustion in the real-life setting of mandatory basic military training

Apolipoprotein E (APOE) ε, catechol-O-methytranferase (COMT) Val108/158Met and brain-derived neurotrophic factor (BDNF) Val66Met single nucleotide polymorphisms (SNPs) were shown to affect stress perception and response. The present study explored possible associations between these SNPs and changes in subclinical anxiety- and depressive symptoms, sense of coherence (SOC) and vital exhaustion (VE) during compulsory basic military training. The study encompassed 179 conscripts of a training base in Greece. The neuropsychiatric assessment was based on the Beck Depression Inventory, the State-Trait Anxiety Inventory, the Antonovsky SOC scale and the Maastricht Questionnaire. It was conducted at three time points of the 19-day basic military training: on day one (baseline), day six (follow-up I) and day 13 (follow-up II). Statistical analyses included Mann-Whitney test, Chi-square test and cross-sectional time series regression models based on the Skillings-Mack statistic. APOE ε4 non-carriers encountered significant changes in anxiety- and depressive symptoms and SOC (in all cases P < 0.001) over the observation period, whilst ε4 carriers did not. The changes in anxiety, depressive symptoms and SOC attained statistical significance in both BDNF Met66 carriers (in all cases P < 0.001) and non-carriers (P = 0.036; < 0.001; < 0.001, respectively) as well as in COMT Met108/158 carriers (P = 0.004; < 0.001; < 0.001, respectively) and non-carriers (P = 0.02; 0.01; 0.021, respectively. Changes over time in VE were not significant (P > 0.05). The observed resistance of APOE ε4 carriers vs non-carriers to changes in anxiety- and depressive symptoms and SOC when exposed to a stressful environment may point to superior coping capacities of healthy young men carrying the ε4 allele.

The 4R's Framework of Nutritional Strategies for Post-Exercise Recovery: A Review with Emphasis on New Generation of Carbohydrates

Post-exercise recovery is a broad term that refers to the restoration of training capacity. After training or competition, there is fatigue accumulation and a reduction in sports performance. In the hours and days following training, the body recovers and performance is expected to return to normal or improve. ScienceDirect, PubMed/MEDLINE, and Google Scholar databases were reviewed to identify studies and position declarations examining the relationship between nutrition and sports recovery. As an evidence-based framework, a 4R’s approach to optimizing post-exercise recovery was identified: (i) Rehydration—a fundamental process that will depend on the athlete, environment and sports event; (ii) Refuel—the consumption of carbohydrates is not only important to replenish the glycogen reserves but also to contribute to the energy requirements for the immune system and tissue reparation. Several bioengineered carbohydrates were discussed but further research is needed; (iii) Repair—post-exercise ingestion of high-quality protein and creatine monohydrate benefit the tissue growth and repair; and (iv) Rest—pre-sleep nutrition has a restorative effect that facilitates the recovery of the musculoskeletal, endocrine, immune, and nervous systems. Nutritional consultancy based on the 4R’s is important for the wise stewardship of the hydration, feeding, and supplementation strategies to achieve a timely recovery.

Neutrophil to Lymphocyte Ratio (NLR) in captive chimpanzees (Pan troglodytes): The effects of sex, age, and rearing

In humans, neutrophil to lymphocyte ratio (NLR) has been used as a clinical tool in diagnosis and/or prognosis of a variety of cancers and medical conditions, as well as in measuring physiological stress over time. Given the close phylogenetic relationship and physical similarities between humans and apes, NLR may similarly be a useful diagnostic tool in assessing chimpanzee health. Only one study has examined NLR in apes, reporting that NLR increased with age and was affected by body-mass index and sex. In the current study, we examined changes in NLR data from longitudinal health records for 443 chimpanzees in two captive chimpanzee populations. Using these data, we analyzed intra-individual changes and inter-individual differences in NLR as a function of age, rearing history, and sex. Contrary to previous studies in humans and the one previous study in chimpanzees, NLR values did not change over a 10-year timespan within individual chimpanzees. However, cross-sectional comparisons revealed a significant quadratic relationship between age and NLR, with the highest values during mid-life (20-30 years of age) and the lowest values in younger and older individuals. Additionally, males and mother-reared individuals had higher NLR than females and nursery-reared chimpanzees, respectively. Lastly, males and those with higher NLR values died at younger ages. These findings suggest that NLR may be useful as a predictor of longevity in chimpanzees. However, given the complexities of these relationships, more research is needed to determine the utility of NLR as a diagnostic health tool for chimpanzees.

Biocultural pathways linking periodontal disease expression to food insecurity, immune dysregulation, and nutrition

OBJECTIVES

In this article, we test theoretical pathways leading to and resulting from periodontal disease to better understand how periodontal disease, which is measurable in both past and present populations, integrates biocultural context and affects whole-body physiology.

METHODS

We use data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 and logistic and linear regressions to test pathways linking psychosocial stress to periodontal disease, and periodontal disease to serum vitamin C levels. We then use causal mediation analysis to test the role of mediating variables in these pathways (n = 1853 individuals).

RESULTS

Food insecurity was positively associated with periodontal disease and negatively associated with serum counts of C-reactive protein (CRP) and neutrophils. Neither CRP nor neutrophils significantly mediated the relationship between food insecurity and periodontal disease. Periodontal disease was negatively associated with serum vitamin C levels and positively associated with neutrophil counts. Neutrophils may mediate the relationship between periodontal disease and vitamin C.

CONCLUSIONS

We identify two main findings: (a) periodontal disease contributes to and may result from immune dysregulation, particularly of neutrophils, and (b) an immune response to chronic infection such as periodontal disease is metabolically expensive for the body to maintain and likely depletes serum micronutrient levels. Both micronutrient status and serum neutrophil counts affect multiple skeletal and physiological phenotypes and thus position periodontal disease in whole-body context.

Scars of childhood socioeconomic stress: A systematic review

Childhood socioeconomic position (SEP) is associated with the development of adult psychological outcomes, with DNA methylation (DNAm) as a mechanism to potentially explain these changes. We present the first systematic review synthesising the literature investigating childhood SEP and DNAm. Thirty-two publications were included. Seventeen studies focused on candidate genes, typically focusing on genes implicated with the stress response and/or development of psychiatric conditions. These studies typically investigated different regions of the genes, which revealed inconsistent results. Six studies calculated epigenetic age, with a small number revealing an elevated significant association with childhood SEP. Epigenome-wide studies revealed altered patterns of DNAm which varied between the nine studies. This research area is emerging and demonstrated great variance in findings with no clear patterns identified across studies. Multiple methodological shortcomings are identified, including at the phenotypic level where construct validity of childhood SEP is highly inconsistent, with studies using a wide range of measures. Larger cohorts will be required with international collaborations to strengthen this research area.

Allostatic Load Indices With Cholesterol and Triglycerides Predict Disease and Mortality Risk in Zoo-Housed Western Lowland Gorillas (Gorilla gorilla gorilla)

Allostatic load, or the physiological dysregulation accumulated due to senescence and stress, is an established predictor of human morbidity and mortality and has been proposed as a tool for monitoring health and welfare in captive wildlife. It is estimated by combining biomarkers from multiple somatic systems into allostatic load indices (ALIs), providing a score representing overall physiological dysregulation. Such ALIs have been shown to predict disease and mortality risk in western lowland gorillas. In these prior analyses, we were unable to include lipid markers, a potential limitation as they are key biomarkers in human models. Recently, we were able to assay serum cholesterol and triglycerides and add them to our previous ALI. We then re-examined associations with health outcomes using binomial generalized linear models. We constructed ALIs using 2 pooling strategies and 2 methods. By itself, a 1-unit increase in allostatic load was associated with higher odds of all-cause morbidity and mortality, but results were mixed for cardiac disease. However, the best fit models for all-cause morbidity and cardiac disease included only age and sex. Allostatic load was retained alongside age in the best fit models for mortality, with a 1-unit increase associated with 23% to 45% higher odds of death. Compared with previous results, ALIs containing cholesterol and triglycerides better predict disease risk in zoo-housed western lowland gorillas, as evidenced by larger effect sizes for some models and better goodness of fit for all ALIs. Based on these results, we address methodology for future allostatic load research on wildlife.

Discrimination Increases the Association Between Parental and Adolescent Allostatic Load in Chinese Rural-to-Urban Migrants

PURPOSE

This study was designed to examine the extent to which parents' allostatic load (AL) and adolescents' perceived discrimination are interrelated in the prediction of adolescents' AL among rural-to-urban migrants in China, as well as the possible buffering role of social support.

METHODS

Multi-informant data were collected in this study. A total of 158 rural-to-urban migrant adolescents (Mean_age = 11.62 years) and one of each of their parents (Mean_age = 39.84 years) were recruited from the suburbs of Beijing, China. Both adolescents' and parents' AL scores were based on 10 physiological indices. Migrant adolescents were asked to report their perceived discrimination and social support.

RESULTS

Parents' AL was significantly positively related to adolescents' AL. The relationship between parents' and adolescents' AL was stronger among adolescents reporting higher perceived discrimination than among those reporting lower. Social support moderated the adverse effects of parents' AL and perceived discrimination on adolescents' AL. Specifically, among adolescents reporting higher social support, the relationships between parents' and adolescents' AL were not significant for those with either high or low perceived discrimination. However, among adolescents reporting lower social support, the positive association was significant for those with high perceived discrimination but not for those with low perceived discrimination.

CONCLUSIONS

Parents' AL was a strong predictor of migrant adolescents' AL, and perceived discrimination acted as a catalyst to increase the association. The relationships of parental AL and perceived discrimination with AL were not significant for adolescents who received high social support.

Implications of accumulative stress burdens during critical periods of early postnatal life for mortality risk among Guale interred in a colonial era cemetery in Spanish Florida (ca. AD 1605-1680)

OBJECTIVE

Research situated within the Developmental Origins of Health and Disease demonstrates that stressors are correlated with future mortality risk, especially if experienced frequently and during early periods of postnatal life. This study examines if the developmental timing and frequency of early life stressors influenced mortality risk for Indigenous Guale in Spanish Florida during the 17th century.

MATERIALS AND METHODS

The present study examines internal enamel microgrowth disruptions (accentuated lines-AL) from Guale individuals (n = 52) interred at Mission Santa Catalina de Guale on St. Catherines Island, Georgia (AD 1605-1680). Teeth were thin-sectioned and microscopically analyzed to document AL variables as predictors of age-at-death.

RESULTS

Individuals with AL died earlier than those without AL. This difference, however, was not significant. Individuals who exhibit AL formed during their first year of life died on average three times earlier than those who did not. The frequency of AL and age-at-first-AL are significantly correlated with age-at-death, and Cox hazard analyses indicates that individuals with early forming and frequent AL had increased risks of early death.

DISCUSSION

This study emphasizes how the lived experiences of Guale children shaped demographic patterns during the 17th century. The survival of early life stressors resulted in life history trade-offs and increased risks for early death. Mortality risks were exacerbated for individuals who experienced frequent stressors during the earliest periods of life. This underscores a role for bioarchaeology in understanding of how accumulative stress burdens during the earliest years of postnatal life may influence mortality risk.

Patterns and variation in the mammal parasite-glucocorticoid relationship

Parasites are ubiquitous and can strongly affect their hosts through mechanisms such as behavioural changes, increased energetic costs and/or immunomodulation. When parasites are detrimental to their hosts, they should act as physiological stressors and elicit the release of glucocorticoids. Alternatively, previously elevated glucocorticoid levels could facilitate parasite infection due to neuroimmunomodulation. However, results are equivocal, with studies showing either positive, negative or no relationship between parasite infection and glucocorticoid levels. Since factors such as parasite type, infection severity or host age and sex can influence the parasite-glucocorticoid relationship, we review the main mechanisms driving this relationship. We then perform a phylogenetic meta-analysis of 110 records from 65 studies in mammalian hosts from experimental and observational studies to quantify the general direction of this relationship and to identify ecological and methodological drivers of the observed variability. Our review produced equivocal results concerning the direction of the relationship, but there was stronger support for a positive relationship, although causality remained unclear. Mechanisms such as host manipulation for parasite survival, host response to infection, cumulative effects of multiple stressors, and neuro-immunomodulatory effects of glucocorticoids could explain the positive relationship. Our meta-analysis results revealed an overall positive relationship between glucocorticoids and parasitism among both experimental and observational studies. Because all experimental studies included were parasite manipulations, we conclude that parasites caused in general an increase in glucocorticoid levels. To obtain a better understanding of the directionality of this link, experimental manipulation of glucocorticoid levels is now required to assess the causal effects of high glucocorticoid levels on parasite infection. Neither parasite type, the method used to assess parasite infection nor phylogeny influenced the relationship, and there was no evidence for publication bias. Future studies should attempt to be as comprehensive as possible, including moderators potentially influencing the parasite-glucocorticoid relationship. We particularly emphasise the importance of testing hosts of a broad age range, concomitantly measuring sex hormone levels or at least reproductive status, and for observational studies, also considering food availability, host body condition and social stressors to obtain a better understanding of the parasite-glucocorticoid relationship.

Elevated hair cortisol is associated with childhood maltreatment and cognitive impairment in schizophrenia and in bipolar disorders

BACKGROUND

The neural diathesis-stress model is useful to understand schizophrenia (SZ) and bipolar (BD) disorders. Childhood maltreatment could affect the Hypothalamic-Pituitary-Adrenal (HPA)-axis and lead to chronic changes in stress-sensitivity, which can be measured with hair cortisol concentrations (HCC), representing long-term, cumulative cortisol levels. Here we investigated if childhood trauma experiences are associated with chronic changes in the HPA axis in severe mental disorders.

METHODS

Participants with SZ or BD (N = 63) and healthy controls (N = 94) were included, and HCC was measured by ELISA. History of childhood maltreatment was assessed using the Childhood Trauma Questionnaire (CTQ). Global function and symptom levels were obtained using the Global Assessment of Functioning (GAF) Scale and the Positive and Negative Syndrome Scale (PANSS). A neuropsychological test battery (MATRICS) was performed to assess cognitive functions.

RESULTS

Our study shows for the first time that patients with a history of childhood maltreatment have higher HCC relative to both healthy controls and patients without a history of childhood maltreatment (P = 0.01, ƞp² = 0.046). In addition, patients experiencing a mood episode had higher HCC than patients in remission (P = 0.03). Lastly, we are the first to show that patients with higher HCC had poorer cognitive performance, specifically working memory (P = 0.01). All associations were irrespective of diagnostic group. A factor analysis confirmed a subgroup within the patients characterized by childhood maltreatment and elevated HCC.

CONCLUSIONS

Findings support the neural diathesis-stress model in SZ and BD pointing to long-term changes in HPA-axis following childhood maltreatment experiences.

The Embodiment of War: Growth, Development, and Armed Conflict

Armed conflict regularly presents extremely adverse circumstances not only for combatants, but also for civilians. In fact, estimates from various wars over the past 70 years suggest that noncombatants comprise the majority of casualties. For survivors, war's effects are often embodied, leaving long-term effects on health and biology. Some of these effects, such as injuries and psychological trauma, are well known. Yet other effects may be subtle and may be elucidated by a developmental biological perspective. In early life, when growth rates are highest, conditions of war may have their greatest impact. Depending on local circumstances, a developing embryo, infant, or child growing in a place embroiled in armed conflict is likely to face—directly or indirectly—various stressors, including malnutrition, infectious disease, and/or psychological stress. Thus, the conditions of war and forced displacement may become embodied, getting under the skin for fundamental biological reasons.

Association of Hair Cortisol Concentration with Prevalence of Major Cardiovascular Risk Factors and Allostatic Load

Background

The high prevalence of cardiovascular diseases cannot be explained completely by conventional risk factors such as older age, smoking, diabetes mellitus, hypertension, obesity, and dyslipidemia. Results of recent studies indicate that chronic stress may be an independent risk factor for cardiovascular morbidity and mortality. Thus, the aim of our study was to investigate the associations between the hair cortisol concentration (HCC), which is considered as a potential biomarker of long-term psychosocial stress, and traditional cardiovascular risk factors, including smoking, dyslipidemia, hypertension, and obesity.

Material/Methods

Fasting blood samples and anthropometric and lifestyle data were collected from 163 apparently healthy men. HCC was determined using high-performance liquid chromatography. Allostatic load (AL) index, defined as an integrated score of multiple interacting systems involved in the adaptation to adverse physical or psychosocial situations, was also calculated.

Results

We found that many prevalent cardiovascular risk factors, including hypertension, smoking, higher than recommended waist circumference (WC), and low-density lipoprotein cholesterol (LDL-C) median values, are associated with higher HCC. Hair cortisol level was also positively associated with the manifestation of individual cardiovascular risk factors such as higher-than-recommended total cholesterol, LDL-C, non-high-density lipoprotein cholesterol, body mass index, and WC median values. Moreover, a significant positive relationship between HCC and AL index was observed.

Conclusions

The results of this study suggest that increased prevalence of traditional cardiovascular risk factors is associated with higher HCC. Also, both HCC and AL index might be appropriate markers for the evaluation of chronic stress level.

Allostatic load, a measure of chronic physiological stress, is associated with pregnancy outcomes, but not fertility, among women with unexplained infertility

STUDY QUESTION

Among infertile women undergoing ovarian stimulation, is allostatic load (AL), a measure of chronic physiological stress, associated with subsequent fertility and pregnancy outcomes?

SUMMARY ANSWER

AL at baseline was not associated with conception, spontaneous abortion or live birth, however, it was significantly associated with increased odds of pre-eclampsia and preterm birth among women who had a live birth in the study.

WHAT IS KNOWN ALREADY

Several studies have linked AL during pregnancy to adverse outcomes including preterm birth and pre-eclampsia, hypothesizing that it may contribute to well-documented disparities in pregnancy and birth outcomes. However, AL biomarkers change over the course of pregnancy, raising questions as to whether gestational AL assessment is a valid measure of cumulative physiologic stress starting long before pregnancy. To better understand how AL may impact reproductive outcomes, AL measurement in the non-pregnant state (i.e. prior to conception) is needed.

STUDY DESIGN, SIZE, DURATION

A secondary data analysis based on data from 836 women who participated in Assessment of Multiple Intrauterine Gestations from Ovarian Stimulation (AMIGOS), a multi-center, randomized clinical trial of ovarian stimulation conducted from 2011 to 2014.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Ovulatory women with unexplained infertility (ages 18-40) were enrolled and at baseline, biological and anthropometric measures were collected. AL scores were calculated as a composite of the following baseline variables determined a priori: BMI, waist-to-hip ratio, systolic blood pressure, diastolic blood pressure, dehydroepiandrosterone sulfate, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, C-reactive protein and HOMA score. Participants received ovarian stimulation for up to four cycles and if they conceived, were followed throughout pregnancy. We fit multi-variable logistic regression models examining AL (one-tailed and two-tailed) in relation to the following reproductive outcomes: conception, spontaneous abortion, live birth, pre-eclampsia, preterm birth and low birthweight.

MAIN RESULTS AND THE ROLE OF CHANCE

Adjusting for covariates, a unit increase in two-tailed AL score was associated with 62% increased odds of pre-eclampsia (OR: 1.62, 95% CI: 1.14, 2.38) 44% increased odds of preterm birth (OR: 1.44, 95% CI: 1.02, 2.08), and 39% increased odds of low birthweight (OR: 1.39, 95% CI: 0.99, 1.97). The relationship between AL and preterm birth was mediated by pre-eclampsia (P = 0.0003). In one-tailed AL analyses, associations were similar, but slightly attenuated. AL was not associated with fertility outcomes (conception, spontaneous abortion, live birth).

LIMITATIONS, REASONS FOR CAUTION

Results may not be generalizable to fertile women who conceive naturally or women with other types of infertility. Comparisons to previous, related work are difficult because variables included in AL composite measures vary across studies. AL may be indicative of overall poor health, rather than being specific to chronic physiological stress.

WIDER IMPLICATIONS OF THE FINDINGS

Our results suggest that chronic physiological stress may not impact success of ovarian stimulation, however, they confirm and extend previous work suggesting that AL is associated with adverse pregnancy outcomes. Physiological dysregulation due to chronic stress has been proposed as a possible mechanism underlying disparities in birth outcomes, which are currently poorly understood. Assessing biomarkers of physiological dysregulation pre-conception or in early pregnancy, may help to identify women at risk of adverse pregnancy outcomes, particularly pre-eclampsia.

STUDY FUNDING/COMPETING INTEREST(S)

Support for AMIGOS was provided by: U10 HD39005, U10 HD38992, U10 HD27049, U10 HD38998, U10 HD055942, HD055944, U10 HD055936 and U10HD055925. Support for the current analysis was provided by T32ES007271, R25HD075737, P30ES001247 and P30ES005022. This research was made possible by funding by American Recovery and Reinvestment Act. The content is solely the responsibility of the authors and does not necessarily represent the official views of NICHD, NIEHS or NIH. E.B., W.V., O.M., R.A., M.R., V.B., G.W.B., C.C., E.E., S.K., R.U., P.C, H.Z., N.S. and S.T. have nothing to disclose. R.L. reported serving as a consultant to Abbvie, Bayer, Kindex, Odega, Millendo and Fractyl and serving as a site investigator and receiving grants from Ferring. K.H. reported receiving grants from Roche Diagnostics and Ferring. R.R. reported a grant from AbbVie. M.D. reported being on the Board of Directors of and a stockholder in Advanced Reproductive Care.

TRIAL REGISTRATION NUMBER

Clinical Trials.gov number: NCT01044862.

Postcranial Skeletal Differences in Free-Range and Captive-Born Primates

Skeletal morphology is important in evolutionary, genetic, developmental, physiological, and functional studies. Although samples from free-ranging individuals may be preferable, constraints of sample size, demography, or conservation status may necessitate the inclusion of captive-born individuals. Captivity may be associated with physical, physiological, or behavioral differences that may affect skeletal form. This study assesses differences in postcranial skeletal form between free-range and captive-born Macaca mulatta and Saguinus oedipus. Samples included free-range M. mulatta from Cayo Santiago (Caribbean Primate Research Center) and captive-born macaques from the Wisconsin National Primate Research Center. S. oedipus samples included free-range born and captive-born individuals from the Oak Ridge Associated Universities Marmoset Research Center. Twenty-four dimensions of various bones, including the scapula, upper limb, innominate and lower limb, were recorded for adults. Age of epiphyseal closure was recorded for immature captive-born M. mulatta. Analysis of variance and principal component analyses tested significant differences between free-range born and captive-born individuals in each species. Significant differences were present in size and shape of postcrania between free-range and captive-born within taxa. Free-range macaques were larger than captive-born macaques, but this pattern did not consistently carry over to the Saguinus samples. Shape differences, while present throughout the skeleton, were especially prominent in the scapula. Differences in developmental timing, nutrition, and physical activity can be expected to contribute to the observed differences in postcranial skeletal form. These differences should be considered when captive-born primates are included in morphological or evolutionary studies. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:761-774, 2019. © 2018 Wiley Periodicals, Inc.