Allostatic load and the assessment of cumulative biological risk in biobehavioral medicine: challenges and opportunities

Immigrant Parent Legal Status and Children's Health in the Hispanic Community Health Study of Latino Youth (SOL Youth)

We assess how immigrant parent legal status shapes children's physical and mental health. Using the Hispanic Community Health Study of Latino Youth-a multi-site dataset-we evaluated mean differences in multiple physical and mental health indicators and parents' and children's stress and resilience by parents' (primarily mothers') legal status (N = 1177). We estimated regression models of two overall child health outcomes-allostatic load and any internalized disorder. Average allostatic load was 28% higher (0.36 standard deviations) and average prevalence of any internalizing disorder was 16% points greater for children of foreign-born unauthorized versus US-born parents. Higher levels of socioeconomic and acculturative stress contributed to children of foreign-born unauthorized parents' heightened health risk, while resilience factors-parental health and familial support-protected their health. Children with unauthorized immigrant parents experience both negative physical and mental health outcomes that can have potential long-term costs.

Allostatic Load in Childhood, Adolescence, and Young Adulthood: Are Assumptions of Measurement Invariance Warranted?

OVERVIEW

Allostatic load represents the cumulative toll of chronic mobilization of the body's stress response systems, as indexed by biomarkers. Higher levels of stress and disadvantage predict higher levels of allostatic load, which, in turn, predict poorer physical and mental health outcomes. To maximize the efficacy of prevention efforts, screening for stress- and disadvantage-associated health conditions must occur before middle age-that is, during childhood, adolescence, and young adulthood. However, this requires that models of allostatic load display properties of measurement invariance across age groups. Because most research on allostatic load has featured older adults, it is unclear if these requirements can be met.

METHODS

To address this question, we fit a series of exploratory and confirmatory analytic models to data on eight biomarkers using a nationally representative sample of N = 4260 children, adolescents, and young adults drawn from the National Health and Nutrition Examination Survey dataset.

RESULTS

Exploratory and confirmatory models indicated that, consistent with allostatic load theory, a unidimensional model was a good fit to the data. However, this model did not display properties of measurement invariance; post-hoc analyses suggested that the biomarkers included in the final confirmatory model were most strongly intercorrelated among young adults and most weakly intercorrelated among adolescents.

CONCLUSIONS

These results underscore the importance of testing assumptions about measurement invariance in allostatic load before drawing substantive conclusions about stress, disadvantage, and health by directly comparing levels of allostatic load across different stages of development, while underscoring the need to expand investigations of measurement invariance to samples of longitudinal data.

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.

Associations of Allostatic Load with Level of and Change in Cognitive Function Among Middle-Aged and Older Hispanic/Latino Adults: The Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA)

Background

Higher allostatic load (AL), a multi-system measure of physiological dysregulation considered a proxy for chronic stress exposure, is associated with poorer global cognition (GC) in older non-Hispanic white adults. However, evidence of these associations in middle-aged and older US-based Hispanic/Latino adults is limited.

Objective

To examine associations of AL with level of cognition, performance in cognition 7 years later, and change in cognition over 7 years among middle-aged and older US-based Hispanic/Latino adults.

Methods

We used data (n = 5,799, 45-74 years at baseline) from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and SOL-Investigation of Neurocognitive Aging (SOL-INCA). The AL score comprised 16 biomarkers representing cardiometabolic, glucose, cardiopulmonary, parasympathetic, and inflammatory systems (higher scores = greater dysregulation). Cognitive outcomes included GC and individual tests of verbal learning and memory, world fluency (WF), Digit Symbol Substitution (DSS), and Trail Making (Parts A & B). Survey-linear regressions assessed associations of AL with performance in cognition at baseline, 7 years later, and via 7-year cognitive change scores adjusting for sociodemographic characteristics, lifestyle factors, and depressive symptoms.

Results

Higher AL was associated with lower baseline performance in GC and WF; and lower 7-year follow-up performance in these same measures plus DSS and Trail Making Parts A & B. Higher AL was associated with more pronounced 7-year change (reduction) in GC and on WF and DSS tests.

Conclusions

Findings extend previous evidence in predominantly older non-Hispanic white cohorts to show that AL is related to level of and change in GC (as well as WF and DSS) among middle-aged and older US-based Hispanic/Latino adults.

Monitoring Social Determinants of Health Assessing Patients and Communities

Because of the devastating health effects of social determinants of health (SDoH), it is important for the primary care provider to assess and monitor these types of stressors. This can be done via surveys, geomapping, or various biomarkers. To date, however, each of these methods is fraught with obstacles. There are currently are no validated "best" SDoH screening tools for use in clinical practice. Nor is geomapping, a perfect solution. Although mapping can collect location specific factors, it does not account for the fact that patients may live in one area, work in another and travel frequently to a third.

Architectural Allostatic Overloading: Exploring a Connection between Architectural Form and Allostatic Overloading

This paper examines, conceptually, the relationship between stress-inducing architectural features and allostatic overload by drawing on literature from neuroimmunology and neuroarchitecture. The studies reviewed from the field of neuroimmunology indicate that chronic or repeated exposure to stress-inducing events may overwhelm the body's regulatory system, resulting in a process termed allostatic overload. While there is evidence from the field of neuroarchitecture that short-term exposure to particular architectural features produce acute stress responses, there is yet to be a study on the relationship between stress-inducing architectural features and allostatic load. This paper considers how to design such a study by reviewing the two primary methods used to measure allostatic overload: biomarkers and clinimetrics. Of particular interest is the observation that the clinical biomarkers used to measure stress in neuroarchitectural studies differ substantially from those used to measure allostatic load. Therefore, the paper concludes that while the observed stress responses to particular architectural forms may indicate allostatic activity, further research is needed to determine whether these stress responses are leading to allostatic overload. Consequently, a discrete longitudinal public health study is advised, one which engages the clinical biomarkers indicative of allostatic activity and incorporates contextual data using a clinimetric approach.

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.

Allostatic load and risk of hearing impairment

Background

Methods

Results

Conclusions

•

Allostatic load captures cumulative physiological stress which has consequence for subsequent hearing function.

•

Prolonged high allostatic load was associated with risk of objectively measured hearing impairment.

•

This association is shown in nationally representative longitudinal ageing study.

Depressive symptoms and allostatic load have a bidirectional association among Puerto Rican older adults

BACKGROUND

Depression is strongly associated with chronic disease; yet, the direction of this relationship is poorly understood. Allostatic load (AL) provides a framework for elucidating depression-disease pathways. We aimed to investigate bidirectional, longitudinal associations of baseline depressive symptoms or AL with 5-year AL or depressive symptoms, respectively.

METHODS

Data were from baseline, 2-year, and 5-year visits of 620 adults (45-75 years) enrolled in the Boston Puerto Rican Health Study. The Center for Epidemiology Studies Depression (CES-D) scale (0-60) captured depressive symptoms, which were categorized at baseline as low (<8), subthreshold (8-15), or depression-likely (⩾16) symptoms. AL was calculated from 11 parameters of biological functioning, representing five physiological systems. Baseline AL scores were categorized by the number of dysregulated parameters: low (0-2), moderate (3-5), or high (⩾6) AL. Multivariable, multilevel random intercept and slope linear regression models were used to examine associations between 3-category baseline CES-D score and 5-year continuous AL score, and between baseline 3-category AL and 5-year continuous CES-D score.

RESULTS

Baseline subthreshold depressive symptoms [(mean (95% CI)): 4.8 (4.5-5.2)], but not depression-likely symptoms [4.5 (4.2-4.9)], was significantly associated with higher 5-year AL scores, compared to low depressive symptoms [4.3 (3.9-4.7)]. Baseline high AL [19.4 (17.6-21.2)], but not low AL [18.5 (16.5-20.6)], was significantly associated with higher 5-year CES-D score, compared to baseline moderate AL [16.9 (15.3-18.5)].

CONCLUSIONS

Depressive symptoms and AL had a bi-directional relationship over time, indicating a nuanced pathway linking depression with chronic diseases among a minority population.

Allostatic load in the context of disasters

Environmental disasters, pandemics, and other major traumatic events such as the Covid-19 pandemic or war contribute to psychosocial stress which manifests in a wide range of mental and physical consequences. The increasing frequency and severity of such events suggest that the adverse effects of toxic stress are likely to become more widespread and pervasive in the future. The allostatic load (AL) model has important elements that lend themselves well for identifying adverse health effects of disasters. Here we examine several articulations of AL from the standpoint of using AL to gauge short- and long-term health effects of disasters and to provide predictive capacity that would enable mitigation or prevention of some disaster-related health consequences. We developed a transdisciplinary framework combining indices of psychosocial AL and physiological AL to produce a robust estimate of overall AL in people affected by disasters and other traumatic events. In conclusion, we urge researchers to consider the potential of using AL as a component in a proposed disaster-oriented human health observing system.

Early experience unpredictability in child development as a model for understanding the impact of the COVID-19 pandemic: A translational neuroscience perspective

Extensive evidence links adverse experiences during childhood to a wide range of negative consequences in biological, socioemotional, and cognitive development. Unpredictability is a core element underlying most forms of early adversity; it has been a focus of developmental research for many years and has been receiving increasing attention recently. In this article, we propose a conceptual model to describe how unpredictable and adverse early experiences affect children's neurobiological, behavioral, and psychological development in the context of the COVID-19 pandemic. We first highlight the critical role of unpredictability in child development by reviewing existing conceptual models of early adversity as they relate to subsequent development across the lifespan. Then, we employ a translational neuroscience framework to summarize the current animal- and human-based evidence on the neurobiological alterations induced by early experience unpredictability. We further argue that the COVID-19 pandemic serves as a global "natural experiment" that provides rare insight to the investigation of the negative developmental consequences of widespread, clustered, and unpredictable adverse events among children. We discuss how the pandemic helps advance the science of unpredictable early adverse experiences. As unpredictability research continues to grow, we highlight several directions for future studies and implications for policymaking and intervention practices.

Adverse childhood experiences and low socioeconomic status with respect to allostatic load in adulthood: A systematic review

Early-life psychosocial stress primes a number of health risk behaviors, and contributes to the development of various mental and somatic disorders in adulthood. It has been reported that adverse childhood experiences (ACEs) and low socioeconomic status (SES) might be associated with allostatic load (AL) in adulthood. In turn, elevated AL index has been found to predict a number of unfavorable health outcomes. Therefore, we aimed to perform a systematic review of studies investigating the association of ACEs and childhood SES with AL in adult populations. Independent online searches covered the publication period up to 20th Jun 2021. A total of 27 studies were included in qualitative synthesis. The majority of eligible studies showed that ACEs (14 out of 19 studies recording ACEs, 73.7%) and low childhood SES (11 out of 12 studies recording childhood SES, 91.7%) are associated with elevated AL in adults. However, several processes were found to mediate or moderate this association. These include educational attainments, social support, health behaviors, adult stress, post-traumatic stress disorder, coping strategies and aging. Moreover, a substantial methodological heterogeneity of approaches to calculating the AL index was observed. Apart from reports from overlapping samples, none of eligible studies used the same set of biomarkers. Findings from this systematic review imply that early-life psychosocial stress might have a lasting impact on biological dysregulations captured by the AL index. Future studies need to explore whether the association between early-life stress and the AL index accounts for the development of specific health outcomes.

Chronic widespread pain in children and adolescents presenting in primary care: prevalence and associated risk factors

ABSTRACT

A significant proportion of children/adolescents report chronic widespread pain (CWP), but little is known about clinically relevant CWP or what factors lead to onset in this population. Objectives were to report the primary care consultation prevalence of CWP and investigate risk factors associated with onset. A validated algorithm for identifying CWP status from primary care electronic healthcare records was applied to a child or adolescent population (aged 8-18 years). The algorithm records patients who have recurrent pain consultations (axial skeleton and upper or lower limbs) or those with a nonspecific generalised pain disorder (eg, fibromyalgia). Prevalence was described, and a nested case-control study was established to identify risk factors associated with CWP onset using logistic regression producing odds ratios (ORs) and 95% confidence intervals (95% CIs). Two hundred seventy-one children or adolescents were identified with CWP, resulting in a 5-year consultation prevalence of 3.19%. Risk factors significantly associated with CWP onset were as follows: mental health (eg, anxiety/neurosis consultations), neurological (eg, headaches), genitourinary (eg, cystitis), gastrointestinal (eg, abdominal pain), and throat problems (eg, sore throats). Children or adolescents with 1 or 2 risk factors (OR 2.15, 95% CI 1.6-2.9) or 3 or more risk factors (OR 9.17, 95% CI 5.9-14.3) were at significantly increased odds of CWP onset compared with those with none. Findings show a significant proportion of the child or adolescent primary care population has CWP. Most risk factors involved pain-related conditions, suggesting potential pathways of pain development. Further work is now needed to better understand the development of CWP in children and adolescents.

Organizational Justice and Long-term Metabolic Trajectories: A 25-Year Follow-up of the Whitehall II Cohort

CONTEXT

Organizational justice has been linked to lower risk of several chronic conditions among employees, but less is known about the long-term mechanisms underlying this risk reduction.

OBJECTIVE

To assess whether self-reported organizational justice is associated with individual and composite long-term metabolic trajectories.

DESIGN

Twenty-five-year follow-up of the Whitehall II prospective cohort study.

SETTING

Middle-aged public servants from the United Kingdom.

PARTICIPANTS

Data on 8182 participants were used.

MAIN OUTCOME MEASURES

Levels of 11 anthropometric, glycemic, lipid, and blood pressure biomarkers were measured at 5 timepoints (1991-2013). We used generalized estimating equations and group-based trajectory modeling to investigate the relationship between organizational justice and biomarker trajectories.

RESULTS

High vs low organizational justice were associated with lower waist (-1.7 cm) and hip (-1 cm) circumference, body mass index (-0.6 kg/m2), triglycerides (-1.07 mmol/L), and fasting insulin (-1.08 µIU/mL) trajectories. Two latent metabolic trajectory clusters were identified: a high- and a low-risk cluster. High organizational justice (vs low) were associated with belonging to the low-risk cluster (pooled odds ratio = 1.47). The low-risk cluster demonstrated lower baseline levels of most biomarkers and better glycemic control, whereas the high-risk cluster showed higher baseline levels of most biomarkers, glycemic deterioration, but also greater improvements in lipid levels over time.

CONCLUSIONS

People with high organizational justice had more favorable long-term cardiometabolic biomarker patterns than those with low organizational justice, indicating a potential mechanism contributing to the lower risk of chronic diseases in the first group. Further intervention studies are warranted to determine whether improvement of organizational justice might improve long-term health.

Examination of the Allostatic Load Construct and Its Longitudinal Association With Health Outcomes in the Boston Puerto Rican Health Study

OBJECTIVE

Despite evidence on allostatic load (AL) as a model explaining associations between stress and disease, there is no consensus on its operationalization. This study aimed to contrast various AL constructs and their longitudinal associations with disease and disability.

METHODS

Baseline and 5-year follow-up data from 738 adults participating in the Boston Puerto Rican Health Study were used. Five AL scores were created by summing the presence of 21 dysregulated multisystem physiological parameters using the following: a) z scores, b) population-based quartile cutoffs, c) clinical-based cutoffs, d) 10 preselected clinical-based cutoffs (AL-reduced), and e) 12 clinical-based cutoffs selected a posteriori based on association with disease (AL-select). Adjusted logistic regression models examined associations between each AL score at baseline and 5-year incident type 2 diabetes (T2D), cardiovascular disease (CVD), activities (or instrumental activities) of daily living (ADL; IADL) for physical impairment, and cognitive impairment.

RESULTS

AL-quartile was associated with greater odds of T2D (odds ratio [OR] = 1.20; 95% confidence interval [CI] = 1.07-1.35) and CVD (OR = 1.14; 95% CI = 1.06-1.22). AL-reduced was associated with higher odds of IADL (OR = 1.21; 95% CI = 1.07-1.37) and AL-clinical with CVD (OR = 1.14; 95% CI = 1.07-1.21), IADL (OR = 1.11; 95% CI = 1.04-1.19), and ADL (OR = 1.15; 95% CI = 1.04-1.26). AL-select showed associations with T2D (OR = 1.35; 95% CI = 1.14-1.61), CVD (OR = 1.21; 95% CI = 1.11-1.32), IADL (OR = 1.15; 95% CI = 1.04-1.26), and ADL (OR = 1.24; 95% CI = 1.08-1.41). No associations were found with AL z-score.

CONCLUSIONS

AL scores computed with clinical-based cutoffs performed robustly in our sample of mainland Puerto Ricans, whereas z scores did not predict disease and disability. AL-select was the most consistent predictor, supporting its use as a disease-predicting model. Future assessment of AL-select in other populations may help operationalize AL.

How biomarker patterns can be utilized to identify individuals with a high disease burden: a bioinformatics approach towards predictive, preventive, and personalized (3P) medicine

Prevalences of non-communicable diseases such as depression and a range of somatic diseases are continuously increasing requiring simple and inexpensive ways to identify high-risk individuals to target with predictive and preventive approaches. Using k-mean cluster analytics, in study 1, we identified biochemical clusters (based on C-reactive protein, interleukin-6, fibrinogen, cortisol, and creatinine) and examined their link to diseases. Analyses were conducted in a US American sample (from the Midlife in the US study, N = 1234) and validated in a Japanese sample (from the Midlife in Japan study, N = 378). In study 2, we investigated the link of the biochemical clusters from study 1 to childhood maltreatment (CM). The three identified biochemical clusters included one cluster (with high inflammatory signaling and low cortisol and creatinine concentrations) indicating the highest disease burden. This high-risk cluster also reported the highest CM exposure. The current study demonstrates how biomarkers can be utilized to identify individuals with a high disease burden and thus, may help to target these high-risk individuals with tailored prevention/intervention, towards personalized medicine. Furthermore, our findings raise the question whether the found biochemical clusters have predictive character, as a tool to identify high-risk individuals enabling targeted prevention. The finding that CM was mostly prevalent in the high-risk cluster provides first hints that the clusters could indeed have predictive character and highlight CM as a central disease susceptibility factor and possibly as a leverage point for disease prevention/intervention.

The Cumulative Impact of Chronic Stressors on Risks of Myocardial Infarction in US Older Adults

OBJECTIVE

This study aimed to investigate the association between cumulative exposure to chronic stressors and the incidence of myocardial infarction (MI) in US older adults.

METHODS

Nationally representative prospective cohort data of adults 45 years and older (n = 15,109) were used to investigate the association between the cumulative number of chronic stressors and the incidence of MI in US older adults. Proportional hazards models adjusted for confounding risk factors and differences by sex, race/ethnicity, and history of MI were assessed.

RESULTS

The median age of participants was 65 years, 714 (4.7%) had a prior MI, and 557 (3.7%) had an MI during follow-up. Approximately 84% of participants reported at least one chronic stressor at baseline, and more than half reported two or more stressors. Multivariable models showed that risks of MI increased incrementally from one chronic stressor (hazard ratio [HR] = 1.28, 95% confidence interval [CI] = 1.20-1.37) to four or more chronic stressors (HR = 2.71, 95% CI = 2.08-3.53) compared with those who reported no stressors. These risks were only partly reduced after adjustments for multiple demographic, socioeconomic, psychosocial, behavioral, and clinical risk factors. In adults who had a prior MI (p value for interaction = .038), we found that risks of a recurrent event increased substantially from one chronic stressor (HR = 1.30, 95% CI = 1.09-1.54) to four or more chronic stressors (HR = 2.85, 95% CI = 1.43-5.69).

CONCLUSIONS

Chronic life stressors are significant independent risk factors for cardiovascular events in US older adults. The risks associated with multiple chronic stressors were especially high in adults with a previous MI.

Evaluating measures of allostatic load in adolescents: A systematic review

BACKGROUND

Adolescents can experience heightened stress due to biopsychosocial changes that occur during this developmental stage. The 'wear and tear' of the physiological systems responsible for managing our stress response can lead to dysregulation of these systems, known as allostatic load (AL). AL is commonly measured within adult populations, however, inconsistencies exist across measures used to quantify the effects of stress on health. The aim of this review was to identify variations in measures across AL studies, and to consider how specific measures may be more appropriate for use within adolescent populations.

METHOD

Pubmed, PsycINFO, PsycARTICLES, Academic Search Complete, were searched in July 2020, using search terms 'allostatic load' and 'adolescence'. AL studies (1988-2020) with an adolescent population (age 10-24 years) were included. 354 records were screened by two reviewers and 41 full-text articles were assessed for eligibility.

RESULTS

25 studies were included in final synthesis. Biomarkers of AL ranged from 1 to 14. The most common index of AL consisted of 6 biomarkers; cortisol, epinephrine, norepinephrine, systolic blood pressure, diastolic blood pressure, and body-mass index.

FINDINGS

Defining measures of AL during adolescence may help to identify vulnerabilities specific to adolescents, which may shape their lifelong health trajectories.

Allostatic Load in Cancer: A Systematic Review and Mini Meta-Analysis

BACKGROUND

Individuals with cancer experience stress throughout the cancer trajectory. Allostatic load (AL), a cumulative multi-system measure, may have a greater value in stress assessment and the associated biological burden than individual biomarkers. A better understanding of the use of AL and its operationalization in cancer could aid in early detection and prevention or alleviation of AL in this population.

PURPOSE

To consolidate findings on the operationalization, antecedents, and outcomes of AL in cancer.

METHODS

Seven databases (CINAHL, Ovid MEDLINE, Web of Science, APA PsycInfo, Scopus, Embase, and Cochrane CENTRAL) were searched for articles published through April 2020. The NIH tools were used to assess study quality.

RESULTS

Twelve studies met inclusion criteria for this review. Although variability existed in the estimation of AL, biomarkers of cardiovascular, metabolic, and immune systems were mostly used. Associations of AL with cancer-specific variables were examined mostly utilizing population-databases. Significant associations of AL with variables such as cancer-related stress, positive cancer history, post traumatic growth, resilience, tumor pathology, and cancer-specific mortality were found. Mini meta-analysis found that a one-unit increase in AL was associated with a 9% increased risk of cancer-specific mortality.

CONCLUSION

This review reveals heterogeneity in operationalization of AL in cancer research and lack of clarity regarding causal direction between AL and cancer. Nevertheless, AL holds a significant promise in cancer research and practice. AL could be included as a screening tool for high-risk individuals or a health outcome in cancer. Optimal standardized approaches to measure AL would improve its clinical utility.

Patterns of change in cardiovascular risk assessments and ankle brachial index among Puerto Rican adults

BACKGROUND

Puerto Rican adults have higher odds of peripheral artery disease (PAD) compared with Mexican Americans. Limited studies have examined relationships between clinical risk assessment scores and ABI measures in this population.

METHODS

Using 2004-2015 data from the Boston Puerto Rican Health Study (BPRHS) (n = 370-583), cross-sectional, 5-y change, and patterns of change in Framingham Risk Score (FRS) and allostatic load (AL) with ankle brachial index (ABI) at 5-y follow-up were assessed among Puerto Rican adults (45-75 y). FRS and AL were calculated at baseline, 2-y and 5-y follow-up. Multivariable linear regression models were used to examine cross-sectional and 5-y changes in FRS and AL with ABI at 5-y. Latent growth mixture modeling identified trajectories of FRS and AL over 5-y, and multivariable linear regression models were used to test associations between trajectory groups at 5-y.

RESULTS

Greater FRS at 5-y and increases in FRS from baseline were associated with lower ABI at 5-y (β = -0.149, P = 0.010; β = -0.171, P = 0.038, respectively). AL was not associated with ABI in cross-sectional or change analyses. Participants in low-ascending (vs. no change) FRS trajectory, and participants in moderate-ascending (vs. low-ascending) AL trajectory, had lower 5-y ABI (β = -0.025, P = 0.044; β = -0.016, P = 0.023, respectively).

CONCLUSIONS

FRS was a better overall predictor of ABI, compared with AL. Puerto Rican adults, an understudied population with higher FRS over 5 years, may benefit from intensive risk factor modification to reduce risk of PAD. Additional research examining relationships between FRS and AL and development of PAD is warranted.

A Systematic Review of the Association between Poverty and Biomarkers of Toxic Stress

Purpose: Toxic stress has been identified as a key mechanism by which poverty impacts health and empirical evidence on the relationship between poverty and biological markers of toxic stress is accumulating. This study synthesizes the empirical evidence of the relationship between poverty and biomarkers of toxic stress. Method: We conduct a systematic literature review using PRISMA guidelines to assess the relationship between poverty and toxic stress. A total of 56 articles are included in the review assessing 63 poverty and toxic stress relationships. Results: Seventeen of 30 reviewed relationships showed a statistically significant relationship between our measures of poverty and biomarker outcomes. Additionally, 12 of the remaining 13 studies demonstrated partially statistically significant relationship between our poverty measures and biomarker outcomes. Conclusion: Findings demonstrate evidence of the relationship between poverty and toxic stress. Consistently, poverty was related to biological stress and neighborhood poverty was related to physical stress outcomes.

Repeated stress exposure in mid-adolescence attenuates behavioral, noradrenergic, and epigenetic effects of trauma-like stress in early adult male rats

Stress in adolescence can regulate vulnerability to traumatic stress in adulthood through region-specific epigenetic activity and catecholamine levels. We hypothesized that stress in adolescence would increase adult trauma vulnerability by impairing extinction-retention, a deficit in PTSD, by (1) altering class IIa histone deacetylases (HDACs), which integrate effects of stress on gene expression, and (2) enhancing norepinephrine in brain regions regulating cognitive effects of trauma. We investigated the effects of adolescent-stress on adult vulnerability to severe stress using the single-prolonged stress (SPS) model in male rats. Rats were exposed to either (1) adolescent-stress (33-35 postnatal days) then SPS (58-60 postnatal days; n = 14), or (2) no adolescent-stress and SPS (58-60 postnatal days; n = 14), or (3) unstressed conditions (n = 8). We then measured extinction-retention, norepinephrine, HDAC4, and HDAC5. As expected, SPS exposure induced an extinction-retention deficit. Adolescent-stress prior to SPS eliminated this deficit, suggesting adolescent-stress conferred resiliency to adult severe stress. Adolescent-stress also conferred region-specific resilience to norepinephrine changes. HDAC4 and HDAC5 were down-regulated following SPS, and these changes were also modulated by adolescent-stress. Regulation of HDAC levels was consistent with the pattern of cognitive effects of SPS; only animals exposed to SPS without adolescent-stress exhibited reduced HDAC4 and HDAC5 in the prelimbic cortex, hippocampus, and striatum. Thus, HDAC regulation caused by severe stress in adulthood interacts with stress history such that seemingly conflicting reports describing effects of adolescent stress on adult PTSD vulnerability may stem in part from dynamic HDAC changes following trauma that are shaped by adolescent stress history.

Stress, allostatic load and mental health in Indigenous Australians

The aim of this narrative review was to demonstrate how the notion of allostatic load (AL) relates directly to the mental health disparities observed between Indigenous and non-Indigenous Australians. We also endeavored to synthesize the results of the limited number of studies examining stress and AL in Indigenous Australians in order to explore the potential public health benefits of the AL concept. A range of literature examining health inequalities, psychosocial determinants of mental illness and AL was explored to demonstrate the applicability of stress biology to the significant mental health burden faced by Indigenous Australians. Furthermore, all original studies indexed in MEDLINE that provided quantitative data on primary stress biomarkers in Indigenous Australians were selected for review. Evidence of hypothalamic-pituitary-adrenal axis dysregulation and increased AL is apparent even in the handful of studies examining stress biomarkers in Indigenous Australians. Urinary, salivary, hair and fingernail cortisol, hair cortisone, urinary epinephrine, heart rate variability and the cortisol awakening response are all AL parameters which have been shown to be dysregulated in Indigenous Australian cohorts. Furthermore, associations between some of these biomarkers, self-perceived discrimination, exposure to stressful life events and symptoms of psychiatric disorders in Indigenous Australians have also been demonstrated. The continued assessment of AL biomarkers and their relationship with past traumas, lifetime stressors and socio-economic factors amongst Indigenous Australians is important to addressing the mental health this population. Measurement of AL biomarkers in a culturally appropriate manner may lead to more targeted preventative measures, interventions and policies, which mitigate the effects of stress at both the individual and societal level.

Job insecurity and risk of coronary heart disease: Mediation analyses of health behaviors, sleep problems, physiological and psychological factors

Job insecurity has been linked to increased risk of coronary heart disease (CHD), but underlying mechanisms remain uncertain. Our aim was to assess the extent to which this association is mediated through life style, physiological, or psychological factors. A total of 3917 men and women free from CHD provided data on job insecurity in the Whitehall II cohort study in 1997-1999. The association between job insecurity and CHD was decomposed into a direct and indirect effect mediated through unhealthy behaviors (smoking, high alcohol consumption, physical inactivity), sleep disturbances, 'allostatic load', or psychological distress. The counterfactual analyses on psychological distress indicated a marginally significant association between job insecurity and incident CHD (hazard ratio (HR) 1.32; 95 % confidence interval (CI) 1.00-1.75). This association was decomposed into a direct (HR 1.22, 95 %CI 0.92-1.63) and indirect association (1.08, 95 %CI 1.01-1.15), suggesting that about 30 % of the total relationship was mediated by psychological distress. No mediation was indicated via health behaviors, sleep disturbances, or allostatic load, although job insecurity was related to disturbed sleep and C-reactive protein, which, in turn were associated with CHD. In conclusion, our results suggest that psychological distress may play a role in the relation between job insecurity and CHD.

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.

Pervasive Discrimination and Allostatic Load in African American and White Adults

OBJECTIVE

This study aimed to examine associations among race, the accumulation of multiple forms of discriminatory experiences (i.e., "pervasive discrimination"), and allostatic load (AL) in African Americans and whites in midlife.

METHODS

Using data collected in 2004 to 2006 from 226 African American and 978 white adults (57% female; mean [SD] age = 54.7 [0.11] years) in the Midlife in the United States II Biomarker Project, a pervasive discrimination score was created by combining three discrimination scales, and an AL score was created based on 24 biomarkers representing seven physiological systems. Linear regression models were conducted to examine the association between pervasive discrimination and AL, adjusting for demographics and medical, behavioral, and personality covariates. A race by pervasive discrimination interaction was also examined to determine whether associations varied by race.

RESULTS

African Americans had higher pervasive discrimination and AL scores than did whites. In models adjusted for demographics, socioeconomic status, medications, health behaviors, neuroticism, and negative affect, a pervasive discrimination score of 2 versus 0 was associated with a greater AL score (b = 0.30, SE = 0.07, p < .001). Although associations seemed to be stronger among African Americans as compared with whites, associations did not statistically differ by race.

CONCLUSIONS

More pervasive discrimination was related to greater multisystemic physiological dysregulation in a cohort of African American and white adults. Measuring discrimination by combining multiple forms of discriminatory experiences may be important for studying the health effects of discrimination.

Multi-Systemic Biological Risk and Cancer Mortality: The NHANES III Study

Multi-systemic biological risk (MSBR), a proxy for allostatic load, is a composite index of biomarkers representing dysregulation due to responses to chronic stress. This study examined the association of an MSBR index with cancer mortality. The sample included n = 13,628 adults aged 20–90 from the NHANES III Linked Mortality File (1988–1994). The MSBR index included autonomic (pulse rate, blood pressure), metabolic (HOMA_ir, triglycerides, waist circumference), and immune (white blood cell count, C-reactive protein) markers. We fit Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CI) of overall cancer mortality risk, according to quartiles (q) of the index. In multivariable models, compared to those in q1, q4 had a 64% increased risk for cancer mortality (HR = 1.64, 95% CI:1.13–2.40). The immune domain drove the association (HR per unit = 1.19, 95% CI:1.07–1.32). In stratified analyses, the HR for those with a BMI ≥ 25 was 1.12 per unit (95% CI:1.05–1.19) and those with a BMI < 25 was 1.04 per unit (95% CI:0.92–1.18). MSBR is positively associated with risk for cancer mortality in a US sample, particularly among those who are overweight or obese. The utilization of standard clinical measures comprising this index may inform population cancer prevention strategies.

Stress, Allostatic Load, and Psychosis: One Step Forward in Research But Where to Go Next?

Stress exposure leads to the activation of several biological mechanisms that have been termed allostasis. These processes enable adaptation to novel situations; however; their prolonged activation exerts systemic and detrimental effects called the allostatic load (AL). The AL concept represents one of useful paradigms to describe biological consequences of chronic stress that might lead to a number of disease outcomes. The AL index, which is a collective measure of cardiovascular, metabolic, neuroendocrine, and immune dysregulations associated with stress exposure, has been found to predict morbidity and mortality in non-clinical populations. Consequently, it has been proposed that the AL concept might be a useful framework to describe biological consequences of chronic stress exposure in patients with psychotic disorders. This perspective article is an overview of studies investigating the AL index and its clinical correlates in patients with psychotic disorders. These studies have consistently reported elevated AL index in patients at the early and chronic course of psychosis. In addition, the AL index has been associated with a higher severity of positive and depressive symptoms, working memory impairments, and lower general functioning. The article provides some critical appraisal of studies in this field and indicates several future directions for investigating the AL concept in psychosis.

Allostatic load index and its clinical correlates at various stages of psychosis

Accumulating evidence indicates systemic biological dysregulations in patients with psychosis that have been conceptualized as the "allostatic load" (AL) index. We aimed to investigate the AL index in 37 subjects at familial high risk of psychosis (FHRP), 42 first-episode psychosis (FEP) patients, 25 acutely relapsed schizophrenia (SCZ-AR) patients and 42 healthy controls (HCs), taking into account psychopathology and cognitive impairment. The AL index was calculated based on 15 biomarkers (cardiovascular markers, anthropometric measures, inflammatory markers, glucose homeostasis parameters, lipids and steroids). Cognition was assessed using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). The AL index was significantly higher in patients with psychosis and FHR-P individuals compared to HCs. Patients with FEP and FHR-P individuals had similar AL index. Moreover, the AL index was significantly higher in SCZ-AR patients compared to other groups of participants. Higher AL index was associated with more severe general psychopathology and depressive symptoms, lower scores of attention (total score, digit span and digit coding tasks) and semantic fluency, as well as worse general functioning in patients with psychosis. There was a significant negative correlation between the AL index and the scores of attention (total score and digit coding task) in FHR-P individuals. No significant correlations between the AL index and cognition were found in HCs. Our results indicate that biological dysregulations, captured by the AL index, appear already in FHR-P individuals and progress with psychotic exacerbations. Elevated AL index might contribute to cognitive impairments in FHR-P individuals and patients with psychosis.

Evaluation of Nutritional Status and Allostatic Load in Adult Patients With Type 2 Diabetes

OBJECTIVE

Diabetes is a chronic disease, affected by nutritional status, and characterized by dysregulations in several systems. Allostatic load is an index that evaluates the dysregulation of all physiological and metabolic systems. This study was conducted to determine the relationship between nutritional status and allostatic load in patients with type 2 diabetes mellitus (T2DM).

METHODS

The study sample consisted of 30 males and 73 females between 20 and 55 years of age. Individuals had T2DM for 7.9±6.17 (mean ± standard deviation) years. World Health Organization criteria cutoffs were used to calculate allostatic load scores. Twelve parameters were questioned and an allostatic load score between 0 and 12 was obtained; values above the cutoff levels were assigned a value of 1, and values in the normal range were assigned a value of 0.

RESULTS

Individuals with high allostatic load comprised a significant portion of the sample (79.6%) for both males and females (73.3% and 82.2%, respectively). Longer diabetes duration was associated with high allostatic load score (p<0.05). There was lower vegetable consumption and higher fruit consumption in the high-allostatic-load group compared with the low-allostatic-load group (p<0.05). However, fruit consumption was still lower than recommended levels in both groups.

CONCLUSIONS

A significant number of individuals had high allostatic load scores in our study. A healthy diet plan in line with the recommendations may help to decrease the allostatic load scores by reducing body weight, waist/hip ratio, blood pressure and fasting blood glucose, and may prevent the negative effects of stress on metabolic processes in the long-term malnutrition in T2DM.

Socioeconomic Adversity, Social Resources, and Allostatic Load Among Hispanic/Latino Youth: The Study of Latino Youth

OBJECTIVE

We examined associations among socioeconomic adversity, social resources, and allostatic load in Hispanic/Latino youth, who are at high risk for obesity and related cardiometabolic risks.

METHODS

Participants were 1343 Hispanic/Latino youth (51% male; ages 8-16 years) offspring of Hispanic Community Health Study/Study of Latinos participants. Between 2012 and 2014, youth underwent a fasting blood draw and anthropometric assessment, and youth and their enrolled caregivers provided social and demographic information. A composite indicator of allostatic load represented dysregulation across general metabolism, cardiovascular, glucose metabolism, lipid, and inflammation/hemostatic systems. Socioeconomic adversity was a composite of caregiver education, employment status, economic hardship, family income relative to poverty, family structure, and receipt of food assistance. Social resources were a composite of family functioning, parental closeness, peer support, and parenting style variables.

RESULTS

Multivariable regression models that adjusted for sociodemographic factors, design effects (strata and clustering), and sample weights revealed a significant, positive, association between socioeconomic adversity and allostatic load (β = .10, p = .035), and a significant, inverse association between socioeconomic adversity and social resources (β = -.10, p = .013). Social resources did not relate to allostatic load and did not moderate or help explain the association of adversity with allostatic load (all p values > .05).

CONCLUSIONS

Statistically significant, but small associations of socioeconomic adversity with both allostatic load and social resources were identified. The small effects may partially reflect range restriction given overall high socioeconomic adversity and high social resources in the cohort.

Social Factors Contributing to the Development of Allostatic Load in Older Adults: A Correlational- Predictive Study

Objetivo: determinar si factores sociales como las condiciones de vivienda, la satisfacción con la casa, las características del vecindario, el apoyo social, las relaciones familiares y la asistencia a la iglesia contribuyen al desarrollo de la carga alostática en los adultos mayores. Materiales y método: se realizó un estudio correlacional y predictivo de corte transversal. Los instrumentos utilizados fueron una hoja de datos sociodemográficos, el instrumento de relaciones familiares percibidas, el cuestionario de Apoyo Social y la Escala de Movilidad Activa en el Entorno Comunitario, versión corta. Los biomarcadores de carga alostática utilizados fueron: presión arterial sistólica y diastólica, índice de masa corporal, circunferencia de la cintura, relación cintura-cadera, colesterol total, lipoproteína de alta densidad, hemoglobina glicosilada, fibrinógeno y proteína C-Reactiva. La muestra se calculó para para el contraste de la hipótesis de no relación (R2 = 0), en un modelo de regresión lineal múltiple con 11 covariables, con un nivel de significancia del .05 y una potencia del 90 % (.90), cuando el coeficinete de determinación poblacional (R2) es .15, tamaño de muestra que resultó en 131 adultos mayores. El análisis estadístico incluyó medidas descriptivas y modelos lineales generalizados. Resultados: los participantes tenían un riesgo medio o alto de carga alostática. El análisis del modelo de regresión lineal multivariante mostró que las mejores condiciones de vivienda, la satisfacción con la propia casa, la presencia de calles sin salida y la asistencia a la iglesia reducen la carga alostática y que el tráfico peligroso aumenta la carga alostática. Conclusiones: existen varios factores sociales que contribuyen al desarrollo de la carga alostática en adultos mayores. Es necesario crear estrategias de cuidado de enfermería hacia el entorno social para disminuir la carga alostática en el adulto mayor.

Allostatic load as a predictor of grey matter volume and white matter integrity in old age: The Whitehall II MRI study

The allostatic load index quantifies the cumulative multisystem physiological response to chronic everyday stress, and includes cardiovascular, metabolic and inflammatory measures. Despite its central role in the stress response, research of the effect of allostatic load on the ageing brain has been limited. We investigated the relation of mid-life allostatic load index and multifactorial predictors of stroke (Framingham stroke risk) and diabetes (metabolic syndrome) with voxelwise structural grey and white matter brain integrity measures in the ageing Whitehall II cohort (N = 349, mean age = 69.6 (SD 5.2) years, N (male) = 281 (80.5%), mean follow-up before scan = 21.4 (SD 0.82) years). Higher levels of all three markers were significantly associated with lower grey matter density. Only higher Framingham stroke risk was significantly associated with lower white matter integrity (low fractional anisotropy and high mean diffusivity). Our findings provide some empirical support for the concept of allostatic load, linking the effect of everyday stress on the body with features of the ageing human brain.

Urban natural environments as nature-based solutions for improved public health - A systematic review of reviews

Increasing urbanisation, changing disease scenarios, and current predictions of climate change impacts require innovative strategies for providing healthy and sustainable cities, now and in the future. The recently coined concept, Nature-based solutions (NBS), is one such strategy referring to actions that are inspired by, supported by, or copied from nature, designed to address a range of environmental challenges. The objective with this article is to evaluate the evidence on public health benefits of exposure to natural environments and explore how this knowledge could be framed within the NBS concept. We conducted a systematic review of reviews following established methodology, including keyword search in several databases, predefined inclusion criteria, and a data extraction in accordance with the PICOS structure. We reviewed literature on associations between public health and natural environments in relation to pathways - sociobehavioural/cultural ecosystem services (e.g. stress and physical activity) and regulating ecosystem services (e.g. heat reduction) - or defined health outcomes (e.g. cardiovascular mortality). The results show that there is strong evidence for improved affect as well as on heat reduction from urban natural environments. These conditions may mediate the effect seen on cardiovascular disease (CVD)-related mortality by exposure to natural environments. By also reviewing existing literature on NBS and health, we phrase the results within the NBS context, providing guidelines on how public health and well-being could be integrated into implementation of NBS for resilient and liveable urban landscapes and health in a changing climate.

Risk and protective factors in the clinical rehabilitation of chronic back pain

OBJECTIVES

Chronic back pain (CBP) can lead to disability and burden. In addition to its medical causes, its development is influenced by psychosocial risk factors, the so-called flag factors, which are categorized and integrated into many treatment guidelines. Currently, most studies investigate single flag factors, which limit the estimation of individual factor significance in the development of chronic pain. Furthermore, factors concerning patients' lifestyle, biography and treatment history are often neglected. Therefore, the objectives of the present study are to identify commonly neglected factors of CBP and integrate them into an analysis model comparing their significance with established flag factors.

METHODS

A total of 24 patients and therapists were cross-sectionally interviewed to identify commonly neglected factors of CBP. Subsequently, the impact of these factors was surveyed in a longitudinal study. In two rehabilitation clinics, CBP patients (n = 145) were examined before and 6 months after a 3-week inpatient rehabilitation. Outcome variables, chronification factor pain experience (CF-PE) and chronification factor disability (CF-D), were ascertained with confirmatory factor analysis (CFA) of standardized questionnaires. Predictors were evaluated using stepwise calculations of simple and multiple regression models.

RESULTS

Through interviews, medical history, iatrogenic factors, poor compliance, critical life events (LEs), social support (SS) type and effort-reward were identified as commonly neglected factors. However, only the final three held significance in comparison to established factors such as depression and pain-related cognitions. Longitudinally, lifestyle factors found to influence future pain were initial pain, physically demanding work, nicotine consumption, gender and rehabilitation clinic. LEs were unexpectedly found to be a strong predictor of future pain, as were the protective factors, reward at work and perceived SS.

DISCUSSION

These findings shed insight regarding often overlooked factors in the development of CBP, suggesting that more detailed operationalization and superordinate frameworks would be beneficial to further research.

CONCLUSION

In particular, LEs should be taken into account in future research. Protective factors should be integrated in therapeutic settings.

Relationship of Psychosocial Resources With Allostatic Load: A Systematic Review

OBJECTIVE

Allostatic load (AL) represents cumulative wear-and-tear on the body and is operationalized as a multisystem index of biomarkers. Allostatic load is associated with morbidities and mortality, leading to a growing body of literature that uses AL as an outcome in its own right. Psychosocial resources (PSRs), such as mastery and social support, may influence health outcomes in part via AL, and the current review seeks to characterize the relations between PSRs and AL.

METHODS

A systematic review was conducted by searching PubMed, CINAHL Plus, PsycINFO, Scopus, and Embase for studies examining the relation between PSR(s) and AL in humans. From 1,417 abstracts screened, 60 full-text articles were reviewed, and 24 studies met inclusion criteria.

RESULTS

Mixed evidence exists for a relationship between PSRs and AL. Most (14/24) studies used a cross-sectional design, and only one study investigated whether a PSR predicted change in AL. Compared to cross-sectional studies, longitudinal studies were more likely to report a significant relationship (8/14 versus 8/10, respectively). Studies with statistically significant main or moderated effects had larger sample sizes than those reporting null effects. Whether a study reported a significant main or moderated relationship did not differ by whether psychological (8/11) or social (10/16) resources were assessed.

CONCLUSIONS

Evidence for a relationship between PSRs and AL is equivocal, and obtained significant relationships are generally small in magnitude. Gaps in the current literature and directions for future research are discussed. Longitudinal studies are needed that repeatedly assess PSRs and AL.

Perceived Weight Discrimination and 10-Year Risk of Allostatic Load Among US Adults

BACKGROUND

Discrimination promotes multisystem physiological dysregulation termed allostatic load, which predicts morbidity and mortality. It remains unclear whether weight-related discrimination influences allostatic load.

PURPOSE

The aim of this study was to prospectively examine 10-year associations between weight discrimination, allostatic load, and its components among adults 25-75 years in the Midlife Development in the US Biomarker Substudy.

METHODS

Participants with information on weight discrimination were analyzed (n=986). At both timepoints, participants self-reported the frequency of perceived weight discrimination across nine scenarios as "never/rarely" (scored as 0), "sometimes" (1), or "often" (2). The two scores were averaged and then dichotomized as "experienced" versus "not experienced" discrimination. High allostatic load was defined as having ≥3 out of 7 dysregulated systems (cardiovascular, sympathetic/parasympathetic nervous systems, hypothalamic pituitary axis, inflammatory, lipid/metabolic, and glucose metabolism), which collectively included 24 biomarkers. Relative risks (RR) were estimated from multivariate models adjusted for sociodemographic and health characteristics, other forms of discrimination, and BMI.

RESULTS

Over 41% of the sample had obesity, and 6% reported weight discrimination at follow-up. In multivariable-adjusted analyses, individuals who experienced (versus did not experience) weight discrimination had twice the risk of high allostatic load (RR, 2.07; 95 % CI, 1.21; 3.55 for baseline discrimination; 2.16, 95 % CI, 1.39; 3.36 for long-term discrimination). Weight discrimination was associated with lipid/metabolic dysregulation (1.56; 95 % CI 1.02, 2.40), glucose metabolism (1.99; 95 % CI 1.34, 2.95), and inflammation (1.76; 95 % CI 1.22, 2.54), but no other systems.

CONCLUSIONS

Perceived weight discrimination doubles the 10-year risk of high allostatic load. Eliminating weight stigma may reduce physiological dysregulation, improving obesity-related morbidity and mortality.

Health and Rural Context Among Victims of Partner Abuse: Does Justice Matter?

Research typically compartmentalizes health and justice as separate areas of study. However, the current health literature on inequality suggests the two concepts are overlapping. For victims of partner violence, procedural justice (defined in this article as access to protective orders and enforcement of protective orders) potentially provides a step toward improved health and well-being by improving safety. There has been limited research examining these factors in rural compared with urban areas. This study examines the impact of procedural justice on health and well-being through interviews with rural and urban women 6 months prior to, and 6 months after, obtaining a protective order. Consistent with other literature, rural women who were victims of partner violence reported worse health, higher stress, and higher Stress-Related Consequences Scale scores compared with urban women. Women's reported health consequences were related to the interaction of perceived ineffectiveness of the protective orders and their rural/urban environment. Thus, the perceived effectiveness of procedural justice may play an important role in alleviating victims' safety, health, and well-being, all of which are components of contemporary views of justice.

Allostatic Load as a Complex Clinical Construct: A Case-Based Computational Modeling Approach

Allostatic load (AL) is a complex clinical construct, providing a unique window into the cumulative impact of stress. However, due to its inherent complexity, AL presents two major measurement challenges to conventional statistical modeling (the field's dominant methodology): it is comprised of a complex causal network of bioallostatic systems, represented by an even larger set of dynamic biomarkers; and, it is situated within a web of antecedent socioecological systems, linking AL to differences in health outcomes and disparities. To address these challenges, we employed case-based computational modeling (CBM), which allowed us to make four advances: (1) we developed a multisystem, 7-factor (20 biomarker) model of AL's network of allostatic systems; (2) used it to create a catalog of nine different clinical AL profiles (causal pathways); (3) linked each clinical profile to a typology of 23 health outcomes; and (4) explored our results (post hoc) as a function of gender, a key socioecological factor. In terms of highlights, (a) the Healthy clinical profile had few health risks; (b) the pro-inflammatory profile linked to high blood pressure and diabetes; (c) Low Stress Hormones linked to heart disease, TIA/Stroke, diabetes, and circulation problems; and (d) high stress hormones linked to heart disease and high blood pressure. Post hoc analyses also found that males were overrepresented on the High Blood Pressure (61.2%), Metabolic Syndrome (63.2%), High Stress Hormones (66.4%), and High Blood Sugar (57.1%); while females were overrepresented on the Healthy (81.9%), Low Stress Hormones (66.3%), and Low Stress Antagonists (stress buffers) (95.4%) profiles.

Neighborhood features and physiological risk: An examination of allostatic load

Poor neighborhoods may represent a situation of chronic stress, and may therefore be associated with health-related correlates of stress. We examined whether lower neighborhood income would relate to higher allostatic load, or physiological well-being, through psychological, affective, and behavioral pathways. Using data from the Biomarker Project of the Midlife in the United States (MIDUS) study and the 2000 Census, we demonstrated that people living in lower income neighborhoods have higher allostatic load net of individual income. Moreover, findings indicate that this relation is partially accounted for by anxious arousal symptoms, fast food consumption, smoking, and exercise habits.

Modeling Multisystem Physiological Dysregulation

OBJECTIVES

The purposes of this study were to compare the relative fit of two alternative factor models of allostatic load (AL) and physiological systems, and to test factor invariance across age and sex.

METHODS

Data were from the Midlife in the United States II Biomarker Project, a large (n = 1255) multisite study of adults aged 34 to 84 years (56.8% women). Specifically, 23 biomarkers were included, representing seven physiological systems: metabolic lipids, metabolic glucose, blood pressure, parasympathetic nervous system, sympathetic nervous system, hypothalamic-pituitary-adrenal axis, and inflammation. For factor invariance tests, age was categorized into three groups (≤45, 45-60, and >60 years).

RESULTS

A bifactor model where biomarkers simultaneously load onto a common AL factor and seven unique system-specific factors provided the best fit to the biomarker data (comparative fit index = 0.967, root mean square error of approximation = 0.043, standardized root mean square residual = 0.028). Results from the bifactor model were consistent with invariance across age groups and sex.

CONCLUSIONS

These results support the theory that represents and operationalizes AL as multisystem physiological dysregulation and operationalizing AL as the shared variance across biomarkers. Results also demonstrate that in addition to the variance in biomarkers accounted for by AL, individual physiological systems account for unique variance in system-specific biomarkers. A bifactor model allows researchers greater precision to examine both AL and the unique effects of specific systems.

Work stress, caregiving, and allostatic load: prospective results from the Whitehall II cohort study

OBJECTIVES

Studies investigating health effects of work and family stress usually consider these factors in isolation. The present study investigated prospective interactive effects of job strain and informal caregiving on allostatic load (AL), a multisystem indicator of physiological dysregulation.

METHODS

Participants were 7007 British civil servants from the Whitehall II cohort study. Phase 3 (1991-1994) served as the baseline, and Phases 5 (1997-1999) and 7 (2002-2004) served as follow-ups. Job strain (high job demands combined with low control) and caregiving (providing care to aged or disabled relatives) were assessed at baseline. AL index (possible range, 0-9) was assessed at baseline and both follow-ups based on nine cardiovascular, metabolic, and immune biomarkers. Linear mixed-effect models were used to examine the association of job strain and caregiving with AL.

RESULTS

High caregiving burden (above the sample median weekly hours of providing care) predicted higher AL levels, with the effect strongest in those also reporting job strain (b = 0.36, 95% confidence interval = 0.01-0.71); however, the interaction between job strain and caregiving was not significant (p = .56). Regardless of job strain, participants with low caregiving burden (below sample median) had lower subsequent AL levels than did non-caregivers (b = -0.22, 95% confidence interval = -0.06--0.37).

CONCLUSIONS

The study provides some evidence for adverse effects of stress at work combined with family demands on physiological functioning. However, providing care to others may also have health protective effects if it does not involve excessive time commitment.

Staging bipolar disorder: what data and what models are needed?

Although bipolar disorder is increasingly recognised as a spectrum of multisystem disorders (ie, bipolar disorders), proposed staging models and theories of bipolar disease progression often fail to incorporate longitudinal data or data from multiple domains of dysfunction. We propose that bipolar disorders are best thought of as syndromes, with different trajectories of development and progression for various symptoms and demographic groups. This inherent complexity might be better suited to non-traditional modelling techniques, potentially derived from chaos theory. In this Personal View, we propose an allostatic load framework to account for biomarkers of physiological symptom progression. We then suggest integration of two potential domains of biobehavioural markers: sleep and wake and circadian rhythm regulation and the behavioural activation system. A satisfactory model should account for the effects of developmental stage as well as demographic characteristics, including but not limited to sex, culture, ethnicity, and socioeconomic status. The ultimate goal of a staging model has to be to inform the development of targeted, stage-appropriate interventions to reduce the substantial burden of bipolar disorders on individuals and societies.

A Longitudinal Investigation of Race, Socioeconomic Status, and Psychosocial Mediators of Allostatic Load in Midlife Women: Findings From the Study of Women's Health Across the Nation

OBJECTIVES

This research sought to assess racial and socioeconomic status (SES) differences in level and change in allostatic load (AL) over time in midlife women and to test whether psychosocial factors mediate these relationships. These factors were discrimination, perceived stress, and hostility.

METHODS

Longitudinal data obtained from the Study of Women's Health Across the Nation were used (n = 2063; mean age at baseline = 46.0 years). Latent growth curve models evaluated the impact of demographic, menopausal, and psychosocial variables on level and change in AL for 8 years.

RESULTS

Direct effects: high levels of discrimination and hostility significantly predicted higher AL (path coefficients = 0.05 and 0.05, respectively). High perceived stress significantly predicted a faster rate of increase of AL (path coefficient = 0.06). Racial and SES differentials were present, with African American race (path coefficient = 0.23), low income (path coefficient = -0.15), and low education (path coefficient = -0.08) significantly predicting high AL level. Indirect effects: significant indirect effects were found for African American race, less income, and lower education through higher discrimination, perceived stress, and hostility on level and rate of AL.

CONCLUSIONS

This was one of the first studies that investigated AL over multiple periods, and results supported AL as a cumulative phenomenon, affected by multiple psychosocial and demographic factors. The results suggest the complex ways in which race, SES, and psychosocial factors operate to influence AL.