Reduction in allostatic load in older adults is associated with lower all-cause mortality risk: MacArthur studies of successful aging

Allostatic Load, Morbidity, and Mortality Among Older Adults: A Multi-Wave Analysis From the National Health and Aging Trends Study

Although allostatic load (AL) is a key concept to reflect physiologic wear and tear from stress, older adults are underrepresented in AL-related research, especially the oldest old (≥80). Further, attenuative factors are often unaccounted for. This longitudinal analysis using data from National Health and Aging Trends Study investigated relationships of AL in 2017 and multi-wave (1) comorbidity accumulation using multilevel Poisson modeling and (2) mortality risk using survival analysis. By year five (2022), each incremental AL increase that older adults (n = 3614) experienced was associated with a 47% increase in comorbidity (p < .001), and a 33% increased mortality risk (p < .001). This research supports a shift to a more proactive, health promotion/risk mitigation paradigm through informing intervention research targeting AL, which is currently scarce. Identifying potentially modifiable and key driving factors influencing the relationship between AL and health among older adults is an important next step to inform intervention design.

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.

Women's fertility and allostatic load in the post-reproductive years: An analysis of the Indonesian Family Life Survey

We know little about the effects of the reproductive health burden in contexts where unsafe abortions, miscarriages, stillbirths, and low-quality maternal care are common. The aim of this study is to investigate the use of allostatic load to understand the impact of reproductive histories on later-life health. We applied path models to the Indonesian Family Life Survey with a sample of 2,001 women aged 40+. Although number of children was not associated with allostatic load, pregnancies not ending in live birth and parenthood before age 18 were both negatively associated with health. We also identified clear cohort and educational effects and a possible rural advantage. Our contribution is twofold: we highlight the importance of reproductive histories beyond live births on women's later-life health in a context of increasing population ageing, and we demonstrate the applicability of using allostatic load to measure health outside the Global North.

Educational patterning in biological health seven years apart: Findings from the Tromsø Study

BACKGROUND

Social-to-biological processes is one set of mechanisms underlying the relationship between social position and health. However, very few studies have focused on the relationship between social factors and biology at multiple time points. This work investigates the relationship between education and the dynamic changes in a composite Biological Health Score (BHS) using two time points seven years apart in a Norwegian adult population.

METHODS

We used data from individuals aged 30 years and above who participated in Tromsø6 (2007-2008) and Tromsø7 (2015-2016) (n = 8117). BHS was defined using ten biomarkers measured from blood samples and representing three physiological systems (cardiovascular, metabolic, inflammatory). The higher the BHS, the poorer the health status.

FINDINGS

Linear regression models carried out on BHS revealed a strong educational gradient at two distinct time points but also over time. People with lower educational attainment were at higher risk of poor biological health at a given time point (βlow education Tromsø6=0.30 [95 %-CI=0.18-0.43] and βlow education Tromsø7=0.30 [95 %-CI=0.17-0.42]). They also presented higher longitudinal BHS compared to people with higher education (βlow education = 0.89 [95 %-CI=0.56-1.23]). Certain biomarkers related to the cardiovascular system and the metabolic system were strongly socially distributed, even after adjustment for sex, age, health behaviours and body mass index.

CONCLUSION

This longitudinal analysis highlights that participants with lower education had their biological health deteriorated to a greater extent over time compared to people with higher education. Our findings provide added evidence of the biological embodiment of social position, particularly with respect to dynamic aspects for which little evidence exists.

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.

Positive life experiences and mortality: Examination of psychobiological pathways

INTRODUCTION AND RATIONALE

Positive life experiences are potentially-rewarding events and behaviors, such as social and romantic interactions, experiences of relaxation and physical comfort, time spent in nature, and other leisure activities. To date, there is limited evidence linking positive life experiences to long-term health outcomes.

OBJECTIVE AND METHODS

The current study used data from N = 1243 participants in the Midlife Development in the US Study Biomarker Project to examine whether greater frequency of a range of different positive experiences and greater level of enjoyment of these experiences was linked to survival over a 12- to-16-year period in Cox proportional hazards models. The potential mediating roles of positive affect, depression, perceived stress, and an allostatic load index of physiological dysregulation in these associations were also examined.

RESULTS

Greater frequency of positive experiences and greater enjoyment of positive experiences were both associated with a reduced hazard of mortality over the 12- to 16-year period. Models assessing a single mediator showed that both associations were mediated by decreased depression and decreased perceived stress, but not by positive affect or allostatic load. In supplementary multi-mediation models, depression was the only significant mediator of the frequency-survival and enjoyment-survival associations.

CONCLUSIONS

Positive life experiences may confer long-term survival benefits, partially through lessening depressive symptomatology.

Sense of purpose in life and allostatic load in two longitudinal cohorts

OBJECTIVE

Sense of purpose in life has been linked with better physical health, longevity, and reduced risk for disability and dementia, but the mechanisms linking sense of purpose with diverse health outcomes are unclear. Sense of purpose may promote better physiological regulation in response to stressors and health challenges, leading to lower allostatic load and disease risk over time. The current study examined the association between sense of purpose in life and allostatic load over time in adults over age 50.

METHODS

Data from the nationally representative US Health and Retirement Study (HRS) and English Longitudinal Study of Ageing (ELSA) were used to examine associations between sense of purpose and allostatic load across 8 and 12 years of follow-up, respectively. Blood-based and anthropometric biomarkers were collected at four-year intervals and used to compute allostatic load scores based on clinical cut-off values representing low, moderate, and high risk.

RESULTS

Population-weighted multilevel models revealed that sense of purpose in life was associated with lower overall levels of allostatic load in HRS, but not in ELSA after adjusting for relevant covariates. Sense of purpose in life did not predict rate of change in allostatic load in either sample.

CONCLUSIONS

The present investigation supports sense of purpose predicting preserved differentiation of allostatic regulation, with more purposeful individuals demonstrating consistently lower allostatic load over time. Persistent differences in allostatic burden may account for divergent health trajectories between individuals low and high in sense of purpose.

Association between early life adversity and allostatic load in girls with precocious puberty

CONTEXT

The mechanisms underlying the elevated long-term health risk in girls with precocious puberty remain unclear, but might result from physiological wear and tear associated with greater exposure to early life adversity.

OBJECTIVE

This study aims to explore early life adversity in girls with precocious puberty and its association with allostatic load.

METHODS

Early life adversity and hair cortisol concentration were measured among 213 girls with precocious puberty (8.21 ± 1.07). Allostatic load score is constructed by using 13 physiological biomarkers representing four systems and hair cortisol concentration. Multivariate linear regression models have estimated the associations between cumulative early life adversity exposure with total and system-specific allostatic load scores. Associations between cumulative early life adversity and the risk of high allostatic load (3 + high-risk biomarkers) were tested using binary logistics regression.

RESULTS

More than two-thirds (67.6%) of girls with central precocious puberty reported two or more early life adversity exposure. Compared to those with no early life adversity exposure, girls who reported early life adversity score ≥ 2 had significantly higher total allostatic load score (β: 1.20-1.64, P < 0.001). Metabolic system was more sensitive to cumulative early life adversity exposure, each form of early life adversity exposure was associated with 0.48-unit increases in metabolic allostatic load score (95%CI: 0.06, 0.90, P = 0.026). Girls reported early life adversity score ≥ 3 were three times more likely to have a high allostatic load compared with those without early life adversity exposure in both unadjusted and adjusted models (OR_adjusted=3.83, 95%CI: 1.17, 12.55, P = 0.001).

CONCLUSION

Multisystem physiological dysregulation is observed in girls with central precocious puberty, which might result from cumulative wear-and-tear associated with early life adversity.

Latent profiles of biological dysregulation and risk of mortality: time-to-event analysis using the Midlife in the US longitudinal study

BACKGROUND

There is a well-established relationship between high allostatic load (AL) and increased risk of mortality. This study expands on the literature by combined latent profile analysis (LPA) with survival data analysis techniques to assess the degree to which AL status is associated with time to death.

METHODS

LPA was employed to identify underlying classes of biological dysregulation among a sample of 815 participants from the Midlife in the US study. Sex-stratified Cox proportional hazards regression models were used to estimate the association between class of biological dysregulation and time to death while controlling for sociodemographic covariates.

RESULTS

The LPA resulted in three classes: low dysregulation, immunometabolic dysregulation and parasympathetic reactivity. Women in the immunometabolic dysregulation group had more than three times the risk of death as compared with women in the low dysregulation group (HR=3.25, 95% CI: 1.47 to 7.07), but that there was not a statistically significant difference between the parasympathetic reactivity group and the low dysregulation group (HR=1.80, 95% CI: 0.62 to 5.23). For men, the risk of death for those in the immunometabolic dysregulation (HR=1.79, 95% CI: 0.88 to 3.65) and parasympathetic reactivity (HR=0.90, 95% CI: 0.34 to 3.65) groups did not differ from the low dysregulation group.

CONCLUSION

The findings are consistent with the previous research that demonstrates increased AL as a risk factor for mortality. Specifically, in women, that increased risk may be associated with immunometabolic dysregulation and not simply a generalised measure of cumulative risk as is typically employed in AL research.

In-hospital stress and patient outcomes: A systematic review and meta-analysis

BACKGROUND

Hospital inpatients are exposed to high levels of stress during hospitalisation that may increase susceptibility to major adverse health events post-hospitalisation (known as post-hospital syndrome). However, the existing evidence base has not been reviewed and the magnitude of this relationship remains unknown. Therefore, the aim of the current systematic review and meta-analysis was to: 1) synthesise existing evidence and to determine the strength of the relationship between in-hospital stress and patient outcomes, and 2) determine if this relationship differs between (i) in-hospital vs post-hospital outcomes, and (ii) subjective vs objective outcome measures.

METHODS

A systematic search of MEDLINE, EMBASE, PsychINFO, CINAHL, and Web of Science from inception to February 2023 was conducted. Included studies reported a measure of perceived and appraised stress while in hospital, and at least one patient outcome. A random-effects model was generated to pool correlations (Pearson's r), followed by sub-group and sensitivity analyses. The study protocol was preregistered on PROSPERO (CRD42021237017).

RESULTS

A total of 10 studies, comprising 16 effects and 1,832 patients, satisfied the eligibility criteria and were included. A small-to-medium association was found: as in-hospital stress increased, patient outcomes deteriorated (r = 0.19; 95% CI: 0.12-0.26; I2 = 63.6; p < 0.001). This association was significantly stronger for (i) in-hospital versus post-hospital outcomes, and (ii) subjective versus objective outcome measures. Sensitivity analyses indicated that our findings were robust.

CONCLUSIONS

Higher levels of psychological stress experienced by hospital inpatients are associated with poorer patient outcomes. However, more high-quality, larger scale studies are required to better understand the association between in-hospital stressors and adverse outcomes.

Allostatic Load Measurement: A Systematic Review of Reviews, Database Inventory, and Considerations for Neighborhood Research

BACKGROUND

Neighborhoods are critical to understanding how environments influence health outcomes. Prolonged environmental stressors, such as a lack of green spaces and neighborhood socioeconomic disadvantage, have been associated with higher allostatic load levels. Since allostatic load levels experienced earlier in life have stronger associations with mortality risk, neighborhoods may be uniquely suited to monitor and mitigate the impacts of environmental stressors. Researchers often study allostatic load in neighborhoods by utilizing administrative boundaries within publicly accessible databases as proxies for neighborhoods.

METHODS

This systematic review of reviews aims to identify commonly used biomarkers in the measurement of allostatic load, compare measurement approaches, inventory databases to study allostatic load, and spotlight considerations referenced in the literature where allostatic load is studied in neighborhoods. The review was conducted using the search term "allostatic load" in the MEDLINE, CINAHL, and PsychINFO databases. The search results were filtered to include reviews.

RESULTS

The search returned 499 articles after deduplication. Overall, 18 synthesis reviews met the inclusion criteria and were retained for extraction. The synthesis reviews analyzed represented 238 studies published from 1995 to 2020. The original ten biomarkers were most often used to measure allostatic load. More recently, body mass index and C-reactive protein have additionally been frequently used to measure allostatic load burden.

CONCLUSIONS

The scientific contributions of this study are that we have identified a clear gap in geographic considerations when studying allostatic load. The implication of this study is that we have highlighted geographic concepts when conducting neighborhood-level research using administrative databases as a neighborhood proxy and outlined emerging future trends that can enable future study of allostatic load in the neighborhood context.

Allostatic Load and Mortality: A Systematic Review and Meta-Analysis

INTRODUCTION

Allostatic load, a measure of stress-related physiologic dysregulation, is associated with numerous mortality risk factors. This systematic review and meta-analysis examines the relationship between high allostatic load (i.e., increased dysregulation versus low dysregulation) and mortality (cardiovascular disease and all-cause mortality).

METHODS

Systematic searches of 2 databases conducted in May 2021 yielded 336 unique records; 17 eligible studies (2001-2020) were included.

RESULTS

High allostatic load was associated with increased risk of all-cause mortality across all the 17 individual studies (hazard ratio=1.08-2.75) and in 6 of 8 studies examining cardiovascular disease mortality (hazard ratio=1.19-3.06). Meta-analyses indicated that high allostatic load was associated with increased risk of all-cause mortality, overall (hazard ratio=1.22, 95% CI=1.14, 1.30, n=10) and across subgroups (hazard ratio=1.11-1.41), and similarly for cardiovascular disease mortality (hazard ratio=1.31, 95% CI=1.10, 1.57, n=6). Although studies were generally of good quality (n=13), heterogeneity was high in most pooled estimates (I²>90%).

DISCUSSION

In this review of relatively good-quality studies, high allostatic load was associated with an increased mortality risk of 22% for all-cause mortality and 31% for cardiovascular disease mortality. Thus, allostatic load is an emerging and potent modifiable risk factor for all-cause and cardiovascular disease mortality that shows promise as a prognostic indicator for mortality. The heterogeneity in allostatic load assessment across studies highlights the need for standardized measurement. The findings underscore the importance of allostatic load's dynamic nature, which may be especially relevant for mitigating mortality risk in younger adults. Because older adults are oversampled, future allostatic load research should prioritize younger adults and longitudinal monitoring and specific cardiovascular disease mortality risk associations and individualize behavioral and lifestyle targets for reducing allostatic load.

Exploring racial disparities on the association between allostatic load and cancer mortality: A retrospective cohort analysis of NHANES, 1988 through 2019

Background

Methods

Results

Conclusions

Impact

•

Allostatic load (AL) is a biologic measure for the ‘wear and tear’ of chronic stress.

•

Studies suggests that racial minorities have higher allostatic load.

•

There is limited knowledge on the association between allostatic and cancer, by race.

•

We observed that AL may increase the risk of cancer death by 14%.

•

Among those aged <40 years, high AL increased cancer death risk by more than 80%.

Association of Allostatic Load and All Cancer Risk in the SWAN Cohort

Elevated chronic stress is thought to increase cancer risk, though the results so far have been inconsistent. In this study, we assessed the relationship between allostatic load (AL), a biological indicator of chronic stress, and overall cancer risk in 3015 women who participated in the Study of Women’s Health Across the Nation (SWAN). Based on the distribution of AL, the study population was categorized into four groups, from the lowest (1st category) to the highest AL group (4th category). At baseline, African American and Hispanic women were more likely to be in the higher AL categories than White women (p < 0.001). In addition, women who smoked regularly, drank alcohol regularly, had no leisure physical activity, and had restless sleep were also more likely to be in the higher AL categories than their relative counterparts (p < 0.001). We also observed that women in the lower-income category with no health insurance were more likely to be in the higher AL category (p < 0.001). The study then found that women in the 4th category of AL (the highest AL group) had a 1.64-fold increased risk of overall cancer (Hazard ratio (HR): 1.64, 95% confidence interval (CI): 1.04, 2.59). The risk association was further strengthened after adjusting demographics, healthy behaviors, and socioeconomic factors with an HR of 2.08. In further analysis of individual biomarkers of AL score, we found that higher levels of triglyceride and CRP were associated with increased risk of cancer, highlighting the role of metabolic dysfunction and inflammation in the etiology of cancer development. In summary, we report that higher AL is associated with increased cancer risk.

Early Life Racial Discrimination, Racial Centrality, and Allostatic Load Among African American Older Adults

BACKGROUND AND OBJECTIVES

Prior research documents accelerated physiological aging among African Americans due to their greater lifetime exposure to social and economic adversity. Yet, less is known about the mechanisms through which early life stressors, such as early life racial discrimination (ELRD), and later life psychosocial resources, such as racial centrality (i.e., importance of Black identity to one's sense of self), interact to shape allostatic load (AL) in adulthood. We evaluate the life course processes linking ELRD, adult racial centrality, and adult AL among older African Americans.

RESEARCH DESIGN AND METHODS

Data from the Nashville Stress and Health Study included African Americans aged 50 and older (N = 260). Poisson regression models assessed the links between ELRD, adult centrality, and adult AL. Interactions determined whether ELRD conditions the centrality-AL association in adulthood.

RESULTS

Adolescent ELRD conferred significantly higher levels of adult centrality and 32% increased risk of high adult AL. Greater adult centrality was linked to high adult AL, but the ELRD-adult AL association was not explained by centrality. However, ELRD and centrality interact to shape adult AL, such that racial centrality was protective against high adult AL for those who experienced racial discrimination as children or adolescents.

DISCUSSION AND IMPLICATIONS

Findings highlight the multiple pathways through which racism-related stressors and psychosocial resources interact to shape physiological dysregulation in later life and underscore the health significance of racial identity for older African Americans. Clinicians and public health professionals should assess early life stressors and foster psychosocial resilience to promote healthy aging.

When Resilience Becomes Risk: A Latent Class Analysis of Psychosocial Resources and Allostatic Load Among African American Men

There is a well-established link between psychosocial risks and psychological health among African American (AA) men. Yet, the psychosocial sources and physical health consequences of resilience (i.e., the ability to maintain good health despite adversity) remain underexplored. Using data from 283 AA men in the Nashville Stress and Health Study, the present study investigated the links between psychosocial resilience and allostatic load (AL), a biological indicator of physiological dysregulation. Latent class analysis (LCA) identified distinct resilience profiles comprising eight psychosocial resources across four categories: coping strategies, sense of control, racial identity, and social support. Analysis of variance (ANOVA) tests determined significant class differences in men's AL scores. LCA results confirm a four-class model was the best fit: Class 1 (high resources, 32%), Class 2 (high coping but low control, 13%), Class 3 (low resources but high racial identity, 20%), and Class 4 (low resources but high mastery, 34%). Results reveal lower AL (better health) among Classes 1 (m = 0.35) and 4 (m = 0.31) and higher AL (worse health) among Classes 2 (m = 0.44) and 3 (m = 0.44). Findings indicate that the "quality" rather than the "quantity" of psychosocial resources matters for physical health among AA men, as positive health outcomes were observed among both low- and high-resource classes. Results suggest different resource combinations produce distinct patterns of resilience among AA men and underscore the need to further elucidate complex resilience processes among this population.

Suicide: Allostatic regulation and resilience

Suicide is a complex public health problem that is the result of a number of intertwined biopsychosocial factors. The diathesis-stress model suggests that suicide is the result of an interaction between genetic vulnerability and environmental stressors. Chronic stress and trauma contribute to biologic adaptations, including hypothalamus-pituitary-adrenal axis dysregulation, that contribute to the degradation of regulatory mechanisms and promote wear and tear the body, represented by allostatic load (AL). AL has been associated with a number of negative outcomes, including mental health problems and suicide. Fortunately, there are pharmacological and non-pharmacological interventions that are effective at reducing AL and reversing its effects. Thus, AL may provide a construct for supporting early risk identification, prevention, and treatment of suicide. AL biomarkers that are amenable to measurable change, effective treatments to reduce AL and perhaps help prevent suicide, and how to best tailor them to the individual and societal levels are important avenues of therapeutic inquiry.

Investigation of Differences in Allostatic Load among Black Men by Level of Educational Attainment: High School Graduates Experience the Highest Levels of Stress

Allostatic load (AL)—the biological assessment of long-term exposure to stress—may explain mortality-rate disparities among non-Hispanic Black (Black) men. We aimed to investigate AL among Black men with equivalent education status after controlling for income. A cross-sectional study was employed to investigate AL among 4113 Black men who participated in the National Health and Nutrition Examination Survey between 1999–2018. A summation of 8 biomarker factors were used to compute AL, differences in socio-demographic characteristics by education status were evaluated, and health behaviors that may influence AL were examined. To determine the high-risk thresholds for each AL component, we examined each component’s distribution among NHB men for whom complete biomarker data were available in the NHANES sample. High-risk thresholds were determined as either (1) above the 75th percentile for body mass index (BMI), diastolic blood pressure (DBP), glycated hemoglobin, systolic blood pressure (SBP), total cholesterol, and serum triglycerides; or (2) below the 25th percentile for serum albumin and serum creatinine. Modified Poisson regression models were used to estimate prevalence ratios and their associated 95% confidence intervals for high AL risk while adjusting for potential confounders. Black men with a high school diploma/GED had a greater prevalence of high AL compared with Black men who had other levels of education, and a slightly higher prevalence of high AL compared with Black men who had less than a high school education. Black men with college degrees had a lower prevalence of high AL than Black men with the lowest levels of educational attainment. Researchers must further examine the hidden costs stemming from the interplay between discrimination associated with being Black in America and systemic racism in the educational system—which may be preventing Black men from achieving optimal health.

Glucocorticoid-Mediated Developmental Programming of Vertebrate Stress Responsivity

Glucocorticoids, vertebrate steroid hormones produced by cells of the adrenal cortex or interrenal tissue, function dynamically to maintain homeostasis under constantly changing and occasionally stressful environmental conditions. They do so by binding and thereby activating nuclear receptor transcription factors, the Glucocorticoid and Mineralocorticoid Receptors (MR and GR, respectively). The GR, by virtue of its lower affinity for endogenous glucocorticoids (cortisol or corticosterone), is primarily responsible for transducing the dynamic signals conveyed by circadian and ultradian glucocorticoid oscillations as well as transient pulses produced in response to acute stress. These dynamics are important determinants of stress responsivity, and at the systemic level are produced by feedforward and feedback signaling along the hypothalamus-pituitary-adrenal/interrenal axis. Within receiving cells, GR signaling dynamics are controlled by the GR target gene and negative feedback regulator fkpb5. Chronic stress can alter signaling dynamics via imperfect physiological adaptation that changes systemic and/or cellular set points, resulting in chronically elevated cortisol levels and increased allostatic load, which undermines health and promotes development of disease. When this occurs during early development it can "program" the responsivity of the stress system, with persistent effects on allostatic load and disease susceptibility. An important question concerns the glucocorticoid-responsive gene regulatory network that contributes to such programming. Recent studies show that klf9, a ubiquitously expressed GR target gene that encodes a Krüppel-like transcription factor important for metabolic plasticity and neuronal differentiation, is a feedforward regulator of GR signaling impacting cellular glucocorticoid responsivity, suggesting that it may be a critical node in that regulatory network.

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.

Cardiometabolic Risk Trajectory Among Older Americans: Findings From the Health and Retirement Study

BACKGROUND

Cardiometabolic risk (CMR) is a key indicator of physiological decline with age, but age-related declines in a nationally representative older US population have not been previously examined.

METHODS

We examined the trajectory of CMR over 8 years of aging, from 2006/2008 to 2014/2016, among 3528 people older than age 50 in the Health and Retirement Study. We used growth curve models to examine change in total CMR as well as in individual cardiometabolic biomarkers to understand how baseline differences and rates of change vary across sociodemographic characteristics, by smoking status, and medication use.

RESULTS

Total CMR did not change among respondents who survived over 8 years. Despite significant differences in CMR across demographic and education groups at baseline, the pace of change with age did not differ by these characteristics. Among individual biomarkers, risk levels of diastolic blood pressure, resting heart rate, and total cholesterol decreased over 8 years while glycosylated hemoglobin, waist circumference, and pulse pressure increased over that time. Both the statistical significance levels and the magnitudes of the reduction over time with age in diastolic blood pressure, resting heart rate, and total cholesterol in models adjusted for age, race/ethnicity, gender, smoking, and education were reduced after controlling for blood pressure and cholesterol medication.

CONCLUSIONS

The relatively constant total CMR level over 8 years occurred because some indicators improved with age while some deteriorated in this period. Medication use contributed to the improvement in blood pressure, resting heart rate, and total cholesterol.

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.

Predictors of Biological Age: The Implications for Wellness and Aging Research

As healthspan and lifespan research breakthroughs have become more commonplace, the need for valid, practical markers of biological age is becoming increasingly paramount. The accessibility and affordability of biological age predictors that can reveal information about mortality and morbidity risk, as well as remaining years of life, has profound clinical and research implications. In this review, we examine 5 groups of aging biomarkers capable of providing accurate biological age estimations. The unique capabilities of these biomarkers have far reaching implications for the testing of both pharmaceutical and non-pharmaceutical interventions designed to slow or reverse biological aging. Additionally, the enhanced validity and availability of these tools may have increasingly relevant clinical value. The authors of this review explore those implications, with an emphasis on lifestyle modification research, and provide an overview of the current evidence regarding 5 biological age predictor categories: Telomere length, composite biomarkers, DNA methylation “epigenetic clocks,” transcriptional predictors of biological age, and functional age predictors.

Association between allostatic load and mortality among Chinese older adults: the Chinese Longitudinal Health and Longevity Study

BACKGROUND

Allostatic load (AL) has shown that high burden of AL is associated with increased risk of adverse outcomes, but little attention has been paid to China with largest ageing population in the world.

OBJECTIVE

This study is to examine the association between AL and all-cause mortality among Chinese adults aged at least 60 years.

DESIGN

Population-based prospective cohort study.

SETTING

In 2011-2012, an ancillary study, in which a blood test was added, including a total of 2439 participants, was conducted in eight longevity areas in the Chinese Longitudinal Healthy Longevity Survey.

PARTICIPANTS

The final analytical sample consisted of 1519 participants (mean±SD age: men 80.5±11.3 years; women 90.2±11.8 years and 53% women).

PRIMARY OUTCOME MEASURE

Cox models were used to examine the association between AL and mortality among men and women, separately. Analyses were also adjusted for potential confounders including age, ethnicity, education and marital status, smoking and exercise.

RESULTS

Male with a medium AL burden (score: 2-4) and high AL burden (score: 5-9) had a 33% and 118% higher hazard of death, respectively, than those with a low AL burden (score: 0-1). We did not find significant difference between females with different levels of AL burden.

CONCLUSION

Higher AL burden was associated with increased all-cause mortality among Chinese men aged at least 60 years. However, we did not find strong association among women. In conclusion, Intervention programmes targeting modifiable components of the AL burden may help prolong lifespan for older adults, especially men, in China.

Stress-related health depreciation: Using allostatic load to predict self-rated health

Approximately one quarter of UK adults are currently diagnosed with two or more chronic conditions, often referred to as multimorbidity. Chronic stress has been implicated in the development of many diseases common to multimorbidity. Policymakers and clinicians have acknowledged the need for more preventative approaches to deal with the rise of multimorbidity and "early ageing". However divergence may occur between an individual's self-rated health and objectively measured health that may preclude preventative action. The use of biomarkers which look 'under the skin' provide crucial information on an individual's underlying health to facilitate lifestyle change or healthcare utilisation. The UK's Understanding Society dataset, was used to examine whether baseline variation in biomarkers measuring stress-related "wear and tear" - Allostatic Load (AL) - predict changes in future self-rated health (SRH) while adjusting for baseline SRH, socioeconomic and lifestyle factors, and healthcare inputs. An interaction between baseline AL and baseline SRH was included to test for differential rates of SRH change. We examined SRH using the SF6D instrument, measuring health-related-quality of life (HRQoL), as well as its physical and mental health components separately. We found that HRQoL and physical health decline faster for those with higher baseline AL (indicating greater "wear and tear") however the same pattern was not observed for mental health. These findings provide novel insights for clinicians and policymakers on the usefulness of AL in capturing health trajectories of which individual's may not be aware and its importance in targeting resilience enhancing measures earlier in the lifecourse to delay physical health decline.

The impact of discrimination on allostatic load in adults: An integrative review of literature

OBJECTIVE

The objective of the paper is to critically review the current state of the literature on the association between discrimination and allostatic load (AL) in adults and determine whether this association differs by sociodemographic characteristics.

METHODS

An extensive literature search was conducted in PubMed, CINAHL, PsycINFO, and Embase to identify studies that investigated the association between discrimination and AL. The search was limited to the English language, articles that were peer-reviewed and articles that were published within the last 10 years.

RESULTS

A total of 11 studies met the eligibility criteria for this review, 8 of which were cross-sectional and 3 of which were longitudinal. There was heterogeneity in the type of discrimination measured, the composition of AL summary score, and the analytic approach utilized to examine the relationship of interest. Nine studies found a significant, positive association between discrimination and AL. The types of discrimination found to be positively associated with AL included lifetime discrimination, childhood racial discrimination, everyday discrimination, and everyday weight discrimination. One study found that this association differed by educational attainment.

CONCLUSION

There is evidence that discrimination is associated with AL. Longitudinal studies with diverse samples are needed to further explore this association and how it differs based on sociodemographic characteristics.

Conceptual and analytical overlap between allostatic load and systemic biological aging measures: Analyses from the National Survey of Midlife Development in the United States

BACKGROUND

Indices quantifying allostatic load (AL) and biological aging (BA) have independently received widespread use in epidemiological literature. However, little attention has been paid to their conceptual and quantitative overlap. By reviewing literature utilizing measures of AL and BA, and conducting comparative analysis, we highlight similarities and differences in biological markers employed and approach toward scale construction. Further, we outline opportunities where both types of indices might be improved by adopting methodological features of the other.

METHODS

Using data from the National Survey of Midlife Development in the United States (N=2,055, age=26-86), we constructed three AL indices: one common literature standard, and two alternative formulations informed by previous work with measures of BA. The performance of AL indices was juxtaposed against two commonly employed BA indices: Klemera-Doubal Method Biological Age and Homeostatic Dysregulation.

RESULTS

All indices correlated with chronological age. Participants with higher AL and older BA performed worse on tests of physical and subjective functioning. Further, participants with increased life-course risk exposure exhibited higher AL and BA. Notably, alternative AL formulations tended to exhibit effect-sizes equivalent to or larger than those observed for BA measures, and displayed superior mortality prediction.

CONCLUSIONS

In addition to their conceptual similarity, AL and BA indices also exhibit significant analytical similarity. Further, BA measures are robust to construction using a panel of biomarkers not observed in previous iterations, including carotenoids indexing antioxidant capacity. In turn, AL indices could benefit by adopting the methodological rigor formalized within BA composites, such as applying biomarker down-selection criteria.

Temporal changes in allostatic load patterns by age, race/ethnicity, and gender among the US adult population; 1988-2018

The objective of this study is to provide an assessment of allostatic load (AL) burden among US adults across race/ethnicity, gender, and age groups over a 30-year time period. We analyzed data from 50,671 participants of the National Health and Nutrition Examination Survey (NHANES) years 1988 through 2018. AL score was defined as the sum total for abnormal measures of the following components: serum albumin, body mass index, serum C - reactive protein, serum creatinine, diastolic blood pressure, glycated hemoglobin, systolic blood pressure, total cholesterol, and serum triglycerides. We performed modified Poisson regression to estimate the adjusted Relative Risks (aRRs) of allostatic load, and generalized linear models to determine adjusted mean differences accounting for NHANES sampling weights. Among US adults aged 18 or older, the prevalence of high AL increased by more than 45% from 1988 to 1991 to 2015-2018, from 33.5% to 48.6%. By the latest period, 2015-2018, Non-Hispanic Black women (aRR: 1.292; 95% CI: 1.290-1.293) and Latina women (aRR: 1.266; 95% CI: 1.265-1.267) had higher risks of AL than non-Hispanic White women. Similar trends were observed among men. Age-adjusted mean AL score among NH-Black and Latinx adults was higher than for NH-Whites of up to a decade older regardless of gender. From 1988 through 2018, Adults aged 40 years old and older had over 2-fold increased risks of high AL when compared to adults 18-29 years old. After 30-years of collective data, racial disparities in allostatic load persist for NH-Black and Latinx adults.

The relationship between traffic-related air pollution exposures and allostatic load score among youth with type 1 diabetes in the SEARCH cohort

OBJECTIVE

We investigated the effects of chronic exposures to particulate and traffic-related air pollution on allostatic load (AL) score, a marker of cumulative biological risk, among youth with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Participants were drawn from five clinical sites of the SEARCH for Diabetes in Youth (SEARCH) study (n = 2338). Baseline questionnaires, anthropometric measures, and a fasting blood test were taken at a clinic visit between 2001 and 2005. AL was operationalized using 10 biomarkers reflecting cardiovascular, metabolic, and inflammatory risk. Annual residential exposures to PM2.5 and proximity to heavily-trafficked major roadways were estimated for each participant. Poisson regression models adjusted for sociodemographic and lifestyle factors were conducted for each exposure.

RESULTS

No significant associations were observed between exposures to PM2.5 or proximity to traffic and AL score, however analyses were suggestive of effect modification by race for residential distance to heavily-trafficked major roadways (p = 0.02). In stratified analyses, residing <100, 100-<200 and 200-<400 m compared to 400 m or more from heavily-trafficked major roadways was associated with 11%, 26% and 14% increases in AL score, respectively (95% CIs: -4, 29; 9, 45; -1, 30) for non-white participants compared to 6%, -2%, and -2% changes (95% CIs: -2, 15; -10, 7; -8, 6) for white participants.

CONCLUSIONS

Among this population of youth with type 1 diabetes, we did not observe consistent relationships between chronic exposures to particulate and traffic-related air pollution and changes in AL score, however associations for traffic-related pollution exposures may differ by race/ethnicity and warrant further examination.

Comparison of the level of allostatic load between patients with major depression and the general population

OBJECTIVE

We compared the level of allostatic load (AL) between patients with major depressive disorder (MDD) and non-depressed controls using two definitions of AL: continuous AL scores (AL index) and clinically significant high AL (≥4). We examined whether MDD was associated with AL independent of basic socioeconomic (age, sex, cohabiting status and level of education) and lifestyle factors (smoking and alcohol use).

METHODS

The MDD patient sample consisted of 177 psychiatric outpatients (mean age 33.7, SD 10.7 years), who were recruited from the Department of Psychiatry at Kuopio University Hospital, Finland, in 2016-19. The non-depressed controls (n = 228, mean age 49.8, SD 10.1 years) lived in the municipality of Lapinlahti, Finland. Ten biomarkers were used to construct the two AL variables. These indicators were systolic and diastolic blood pressure, total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, glucose, creatinine, waist circumference, body mass index (BMI) and C-reactive protein (CRP).

RESULTS

The mean AL scores did not significantly differ between MDD patients (2.97) and non-depressed controls (3.12), thus it was not associated with MDD in univariate analysis. In multivariate models a higher AL index was associated with a 1.42 to 1.82 times higher likelihood of belonging to the MDD group. Furthermore, we found that high AL (i.e. AL ≥ 4) was associated with MDD, with the likelihood ranging between 2.27 and 2.96 compared with the non-depressed controls in multivariate models.

CONCLUSIONS

Even young adult patients with MDD appear to display clinically significant, high AL compared with non-depressed controls. Thus, it is important to pay attention to the somatic health of depressed patients in addition to their mental health.

Stress and Allostatic Load Among Latina/os: Evidence from the Hispanic Community Health Study/Study of Latina/os

We investigated associations between measures of environmental and psychological stress (i.e., chronic stress and perceived stress) and allostatic load across gender. We also tested whether other important intersectional factors, such as ethnic background and nativity, moderated stress-allostatic load relationships. Data were drawn from the Hispanic Community Health Study/ Study of Latina/os, a representative, multi-ethnic sample of Latina/os living in four urban communities. The final analytic sample consisted of 3848 Latina/os from five ethnic groups: Cuban, Puerto Rican, Dominican, Mexican, and South/ Central American. Findings indicate greater chronic and perceived stress were significantly associated with allostatic load for males but not for females. We also find, in some cases, ethnic background and nativity moderated relationships between types of stress and allostatic load for males. Findings suggest that environmental and psychological stressors can potentially shape health profiles of Latino males, with important differences across ethnic background and nativity.

Transcriptomics of Long-Term Meditation Practice: Evidence for Prevention or Reversal of Stress Effects Harmful to Health

Background and Objectives: Stress can overload adaptive mechanisms, leading to epigenetic effects harmful to health. Research on the reversal of these effects is in its infancy. Early results suggest some meditation techniques have health benefits that grow with repeated practice. This study focused on possible transcriptomic effects of 38 years of twice-daily Transcendental Meditation^® (TM^®) practice. Materials and Methods: First, using Illumina^® BeadChip microarray technology, differences in global gene expression in peripheral blood mononuclear cells (PBMCs) were sought between healthy practitioners and tightly matched controls (n = 12, age 65). Second, these microarray results were verified on a subset of genes using quantitative polymerase chain reaction (qPCR) and were validated using qPCR in larger TM and control groups (n = 45, age 63). Bioinformatics investigation employed Ingenuity^® Pathway Analysis (IPA^®), DAVID, Genomatix, and R packages. Results: The 200 genes and loci found to meet strict criteria for differential expression in the microarray experiment showed contrasting patterns of expression that distinguished the two groups. Differential expression relating to immune function and energy efficiency were most apparent. In the TM group, relative to the control, all 49 genes associated with inflammation were downregulated, while genes associated with antiviral and antibody components of the defense response were upregulated. The largest expression differences were shown by six genes related to erythrocyte function that appeared to reflect a condition of lower energy efficiency in the control group. Results supporting these gene expression differences were obtained with qPCR-measured expression both in the well-matched microarray groups and in the larger, less well-matched groups. Conclusions: These findings are consistent with predictions based on results from earlier randomized trials of meditation and may provide evidence for stress-related molecular mechanisms underlying reductions in anxiety, post-traumatic stress disorder (PTSD), cardiovascular disease (CVD), and other chronic disorders and diseases.

Minimum clinical important difference for resilience scale specific to cancer: a prospective analysis

BACKGROUND

The minimum clinical important differences (MCIDs) of resilience instruments in patients with cancer have not been comprehensively described. This study was designed to evaluate MCIDs of 10-item and 25-item resilience scales specific to cancer (RS-SC-10 and RS-SC-25).

METHODS

From June 2015 to December 2018, RS-SCs were longitudinally measured in 765 patients with different cancer diagnoses at baseline (T0) and 3 months later (T1). The EORTC QLQ-C30, Connor-Davidson Resilience Scale, Hospital Anxiety and Depression Scale, and Allostatic Load Index were measured concurrently as anchors. Anchor-based methods (linear regression, within-group), distribution-based methods(within-group), and receiver operating characteristic curves (ROCs, within-subject) were performed to evaluate the MCIDs.

RESULTS

623 of 765 (84.1%) patients had paired RS-SCs scores. Moderate correlations were identified between the change in RS-SCs and change in anchors (r = 0.38-0.44, all p < 0.001). Linear regression estimated + 8.9 and - 6.7 as the MCIDs of RS-SC-25, and + 3.4 and - 2.5 for RS-SC-10. Distribution-based methods estimated + 9.9 and - 9.9 as the MCIDs of RS-SC-25, and + 4.0 and - 4.0 for RS-SC-10. ROC estimated + 5.5 and - 4.5 as the MCIDs of RS-SC-25, and + 2.0 and - 1.5 for RS-SC-10.

CONCLUSIONS

The most reliable MCID is around 5 points for RS-SC-25 and 2 points for RS-SC-10. RS-SCs are more responsive to the worsening status of resilience in patients with cancer and these estimates could be useful in future resilience-based intervention trials.

Chronic stress and arthritis: a scoping review

OBJECTIVE

Emerging research supports the role of chronic stress in chronic disease development. This scoping review aimed to map the field of research exploring relationships between chronic stress and the development of arthritis in adult populations.

METHODS

Five electronic databases were systematically searched without publication limits based on three key concepts: stress, arthritis and adults. Eligible qualitative studies investigated individuals' perceived causes of arthritis; quantitative studies investigated relationships between exposure to a chronic stressor and an arthritis presence outcome. Articles were screened by two independent reviewers and data were narratively synthesised.

RESULTS

Of 1819 unique records, 54 studies met inclusion criteria. Nine studies used qualitative methods and 45 used quantitative methods. Studies increased chronologically, with half (n = 27) published since 2010. Chronic stress exposures were heterogenous; most were categorised as adverse life events (n = 22) or adverse childhood experiences (n = 17). Self-reported arthritis was the most frequent measure of arthritis outcome (n = 26) in quantitative studies. A majority of studies (n = 41) suggested a relationship between exposure to chronic stressors and arthritis development.

CONCLUSION

Increasing study numbers in the past decade may reflect increasing awareness of the potential impact of chronic stress in arthritis development, consistent with a biopsychosocial approach to chronic disease aetiology and management. Further research, using precise arthritis definitions, conducted within a clearly articulated pathophysiological framework, is required to establish a causal relationship between exposure to chronic stressors and the development of specific arthritis conditions.

Education, biological ageing, all-cause and cause-specific mortality and morbidity: UK biobank cohort study

BACKGROUND

Socioeconomic position as measured by education may be embodied and affect the functioning of key physiological systems. Links between social disadvantage, its biological imprint, and cause-specific mortality and morbidity have not been investigated in large populations, and yet may point towards areas for public health interventions beyond targeting individual behaviours.

METHODS

Using data from 366,748 UK Biobank participants with 13 biomarker measurements, we calculated a Biological Health Score (BHS, ranging from 0 to 1) capturing the level of functioning of five physiological systems. Associations between BHS and incidence of cardiovascular disease (CVD) and cancer, and mortality from all, CVD, cancer, and external causes were examined. We explored the role of education in these associations. Mendelian randomisation using genetic evidence was used to triangulate these findings.

FINDINGS

An increase in BHS of 0.1 was associated with all-cause (HR = 1.14 [1.12-1.16] and 1.09 [1.07-1.12] in men and women respectively), cancer (HR = 1.11 [1.09-1.14] and 1.07 [1.04-1.10]) and CVD (HR = 1.25 [1.20-1.31] and 1.21 [1.11-1.31]) mortality, CVD incidence (HR = 1.15 [1.13-1.16] and 1.17 [1.15-1.19]). These associations survived adjustment for education, lifestyle-behaviours, body mass index (BMI), co-morbidities and medical treatments. Mendelian randomisation further supported the link between the BHS and CVD incidence (HR = 1.31 [1.21-1.42]). The BHS contributed to CVD incidence prediction (age-adjusted C-statistic = 0.58), other than through education and health behaviours.

INTERPRETATION

The BHS captures features of the embodiment of education, health behaviours, and more proximal unknown factors which all complementarily contribute to all-cause, cancer and CVD morbidity and premature death.

Personality Traits, Coping, Health-related Behaviors, and Cumulative Physiological Health in a National Sample: 10 Year Prospective Effects of Conscientiousness via Perceptions of Activity on Allostatic Load

BACKGROUND

Personality traits, coping styles, and health-related behaviors show associations with various aspects of health. However, integrative life-course investigations of pathways by which these factors might affect later cumulative physiological health risk remain sparse.

PURPOSE

To investigate prospective associations of personality traits via coping styles and health-related behaviors on allostatic load in a national sample.

METHODS

Using data from the Midlife in the United States study (MIDUS; N = 1,054), path analyses were used to test direct and indirect associations (via coping styles, smoking, frequency of alcohol consumption, leisure-time physical activity, and perceptions of activity) of personality traits on a latent measurement model of allostatic load informed by 10 biomarkers associated with cardiovascular, inflammation, glucose, and lipid subsystems.

RESULTS

Direct 10 year associations of greater conscientiousness on healthier allostatic load and greater extraversion on less healthy allostatic load were observed. Consistent with hypothesized behavioral pathways, relationships between conscientiousness and extraversion on allostatic load were prospectively mediated by greater perceptions of activity. Physical activity and more frequent alcohol use were associated with healthier allostatic load but did not act as prospective mediators.

CONCLUSIONS

The results provide further evidence of conscientiousness' standing as a marker of health via cumulative physiological health. Moreover, a greater perception of activity was identified as a pathway through which conscientious individuals experienced healthier physiological profiles over time. Examining a more detailed picture of the psychosocial mechanisms leading to development of health risk, as was found with perceptions of activity, remains an important area for future research.

Does the choice of Allostatic Load scoring algorithm matter for predicting age-related health outcomes?

Allostatic Load (AL) is posited to provide a measure of cumulative physiological dysregulation across multiple biological systems and demonstrates promise as a sub-clinical marker of overall health. Despite the large heterogeneity of measures employed in the literature to represent AL, few studies have investigated the impact of different AL scoring systems in predicting health. This study uses data for 4477 participants aged 50+ years participating in the Irish Longitudinal Study on Ageing (TILDA) to compare the utility of 14 different scoring algorithms that have been used to operationalise AL (i.e. count-based high-risk quartiles, deciles, two-tailed cut-points, z-scores, system-weighted indices, clinical cut-points, sex-specific scores, and incorporating medication usage). Model fit was assessed using R², Bayesian Information Criterion (BIC), and the area under the Receiver Operating Characteristic curve (AUC). The measure incorporating medications predicted walking speed and SRH marginally better than others. In general, AL was not predictive of grip strength. Overall, the results suggest that the choice of AL scoring algorithm exerts a relatively modest influence in predicting a number of important health outcomes.

A scoping review of interventions targeting allostatic load

Allostatic load (AL) is the manifestation of cumulative responses to chronic stress exposure. Numerous studies have shown the importance of AL in understanding disease risks. Yet little is known about existing interventions that target AL specifically. We aimed to address this gap by identifying interventions targeting AL and determining the success of these interventions in improving biological functioning. We searched five electronic databases using variations of two concepts: AL and programs or interventions. We included original research reports that focused on AL as an outcome. We excluded work that focused on a single indicator, not written in English or did not implement an intervention. The Template for Intervention Description and Replication checklist guided our intervention critique and synthesis. Six articles were included, with sample size across the interventions ranging between 2 and 733. Despite inconsistencies in the selection of AL indicators and scoring of AL, all four body systems were represented in all the studies. Four interventions showed significant improvement in Al (as indicated by a decrease in AL score) as early as 7 weeks. More interventions targeting Al are needed. The reduction in AL scores among four of the six interventions suggests that Al could be a biological outcome measure that is sensitive to change in response to interventions. This has significant clinical and research implications. Future studies are needed to examine whether AL serves as a mediator in the effects of the intervention on improving clinical manifestations of diseases.

Association of Allostatic Load with All-Cause andCancer Mortality by Race and Body Mass Index in theREGARDS Cohort

Among 29,701 Black and White participants aged 45 years and older in the Reasons for Geographic and Racial Difference in Stroke (REGARDS) study, allostatic load (AL) was defined as the sum score of established baseline risk-associated biomarkers for which participants exceeded a set cutoff point. Cox proportional hazard regression was utilized to determine the association of AL score with all-cause and cancer-specific mortality, with analyses stratified by body-mass index, age group, and race. At baseline, Blacks had a higher AL score compared with Whites (Black mean AL score: 2.42, SD: 1.50; White mean AL score: 1.99, SD: 1.39; p < 0.001). Over the follow-up period, there were 4622 all-cause and 1237 cancer-specific deaths observed. Every unit increase in baseline AL score was associated with a 24% higher risk of all-cause (HR: 1.24, 95% CI: 1.22, 1.27) and a 7% higher risk of cancer-specific mortality (HR: 1.07, 95% CI: 1.03, 1.12). The association of AL with overall- and cancer-specific mortality was similar among Blacks and Whites and across age-groups, however the risk of cancer-specific mortality was higher among normal BMI than overweight or obese participants. In conclusion, a higher baseline AL score was associated with increased risk of all-cause and cancer-specific mortality among both Black and White participants. Targeted interventions to patient groups with higher AL scores, regardless of race, may be beneficial as a strategy to reduce all-cause and cancer-specific mortality.

Stress Measured by Allostatic Load Varies by Reason for Immigration, Age at Immigration, and Number of Children: The Africans in America Study

Stress leads to physiologic dysfunction and cardiometabolic disease. Allostatic load score (ALS) measures stress-induced cardiovascular, metabolic, and inflammatory biomarkers. We estimated the odds of high ALS by reason for and age at immigration, duration of American residence, number of children, and socioeconomic status in 193 African immigrants (male: 65%, age 41 ± 10 y (mean ± Standard Deviation (SD)), range 22–65 y). ALS was calculated with High-ALS defined as ALS ≥ 3.0 and Low-ALS defined as ALS < 3.0. Oral glucose tolerance tests (OGTT) were performed, the cardiovascular disease (CVD) risk estimated, and TNF-α, an inflammatory cytokine, measured. Logistic regression was used to estimate odds of High-ALS. In the High- and Low-ALS groups, ALS were 4.0 ± 1.2 vs. 1.3 ± 0.7, diabetes prevalence: 14% vs. 4%, CVD risk: 23% vs. 8%, TNF-α levels: 15 ± 9 vs. 11 ± 6 pg/mL, respectively (all p ≤ 0.01). Immigrants were more likely to be in the High-ALS group if their reason for immigration was work or asylum/refugee (OR 2.18, p = 0.013), their age at immigration was ≥30 y (OR 3.28, p < 0.001), their duration of residence in United States was ≥10 y (OR 3.16, p = 0.001), or their number of children was ≥3 (OR 2.67, p = 0.019). Education, income, health insurance, marital status, and gender did not affect High-ALS odds. Factors adversely influencing allostatic load and cardiometabolic health in African immigrants were age at and reason for immigration, duration of residence in America, and number of children.

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.

Neighborhood perceptions and allostatic load: Evidence from Midlife in the United States study

Allostatic load, which represents the cumulative wear and tear on physiological systems resulting from long-term exposure to stress, provides a theoretical framework that can be applied to understand the association between neighborhood conditions and health outcomes. Within allostatic load theory perception plays a key role, as the cognitive appraisal process associated with one's perceptions determines whether external stimuli-such as neighborhood conditions-are deemed threatening or benign. With data from the Midlife Development in the United States, this study employed structural equation modeling to assess the association between neighborhood perceptions and cumulative, systems-level allostatic load scores. The findings demonstrate that neighborhood perception, as operationalized as a combination of perceived trust in neighbors, perceived neighborhood safety, and perceived neighborhood conditions, was inversely associated with allostatic load even when controlling for objective neighborhood conditions.

A Genetically Informed Study of Neighborhoods and Health: Results From the MIDUS Twin Sample

OBJECTIVES

To examine whether neighborhood income and neighborhood safety concerns influence multisystem physiological risk after adjusting for genetic and environmental selection effects that may have biased previous tests of this association.

METHODS

We used structural equation modeling with a genetically informed sample of 686 male and female twin pairs in the Midlife in the United States Study II (2004).

RESULTS

Controlling for additive genetic and shared environmental processes that may have biased neighborhood-health links in previous examinations, higher neighborhood safety concerns were associated with less physiological risk among women but not men.

DISCUSSION

Our findings suggest a possible causal role of neighborhood features for a measure of physiological risk that is associated with the development of disease. Efforts to increase neighborhood safety, perhaps through increased street lighting or neighborhood watch programs, may improve community-level health.

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.

Racial/ethnic inequities in the associations of allostatic load with all-cause and cardiovascular-specific mortality risk in U.S. adults

Non-Hispanic blacks have higher mortality rates than non-Hispanic whites whereas Hispanics have similar or lower mortality rates than non-Hispanic blacks and whites despite Hispanics' lower education and access to health insurance coverage. This study examines whether allostatic load, a proxy for cumulative biological risk, is associated with all-cause and cardiovascular (CVD)-specific mortality risks in US adults; and whether these associations vary with race/ethnicity and further with age, sex and education across racial/ethnic groups. Data from the third National Health and Nutritional Examination Survey (NHANES III, 1988-1994) and the 2015 Linked Mortality File were used for adults 25 years or older (n = 13,673 with 6,026 deaths). Cox proportional hazards regression was used to estimate the associations of allostatic load scores (2 and ≥3 relative to ≤1) with a) all-cause and b) CVD-specific mortality risk among NHANES III participants before and after controlling for selected characteristics. Allostatic load scores are associated with higher all-cause and CVD-specific mortality rates among U.S. adults aged 25 years or older, with stronger rates observed for CVD-specific mortality. All-cause mortality rates for each racial/ethnic group differed with age and education whereas for CVD-specific mortality rates, this difference was observed for sex. Our findings of high allostatic load scores associated with all-cause and CVD-specific mortality among US adults call attention to monitor conditions associated with the allostatic load's biomarkers to identify high-risk groups to help monitor social inequities in mortality risk, especially premature mortality.

Going the distance: The diurnal range of cortisol and its association with cognitive and physiological functioning

Cortisol features prominently in theories describing how chronic stress wears away at physical and cognitive health. The current study examines composite measures of physiological and cognitive functioning in relation to two aspects of daily cortisol: total daily output and change in levels throughout the day. Participants (N = 1001; aged 28-84 years-old) from the Midlife Development in the United States (MIDUS) study provided 4 daily saliva samples across four consecutive days and underwent a physical exam that provided information about six inter-related physiological systems that were combined into a measure of allostatic load. They also completed a phone-based battery of cognitive tasks, which provided a composite score combining memory, reasoning, and speed of processing performance. Total daily cortisol output was captured using area under the curve with respect to ground (AUCg). Change in cortisol levels was assessed using two methods: slope, calculated through piecewise spline models, and dynamic range, calculated by the difference between the day's highest and lowest log-cortisol levels. Findings indicate that, when examined together, overall cortisol output was not associated with either outcome, but a greater range in cortisol throughout the day was associated with both lower allostatic load and higher cognitive functioning. Results emphasize the importance of dynamic daily processes, assessed either using slopes or dynamic range, to both physiological and cognitive functioning.

Pilot Study on the Effect of Biophysical Therapy on Salivary Alpha-Amylase as a Surrogate Measure of Anxiety/Stress: In Search of a Novel Noninvasive Molecular Approach for the Management of Stress

Anxiety and depression impact dramatically on public health, underlying the importance of alternative cost-effective treatments. Previous studies have shown that biophysical treatment can significantly reduce anxiety symptoms and recently, salivary alpha-amylase (SAA) has been identified as an objective correlate of the sympathetic-parasympathetic imbalance related to increased stress burden, defined as allostatic load. The aim of this study was to evaluate the effect of biophysical therapy on SAA levels, in addition to the Depression Anxiety Stress Scale (DASS)-21 questionnaire. Twenty-four workers (sales representatives) presenting with mild anxiety/stress symptoms (Generalized Anxiety Disorder 7-item scale of > 5) were randomized to biophysical treatment (N = 12) or placebo control (N = 12). The biophysical group underwent electromagnetic information transfer through an aqueous system procedure, with daily self-administration for one month. SAA collection and the DASS-21 questionnaire were undertaken at baseline and after one month in all patients. Clinical characteristics and baseline DASS-21 subscale scores were similar between placebo and biophysical group at baseline. After one month, patients receiving biophysical therapy had significantly reduced SAA levels compared to the placebo group (27.8 ± 39.4 vs. 116.8 ± 114.9 U/mL, p = 0.019). All three DASS-21 subscales, depression (9.3 ± 5.1 vs. 5.7 ± 5.5, p = 0.1), anxiety (6.7 ± 25 vs. 3.7 ± 2.2, p = 0.0049) and stress (10.8 ± 4.2 vs. 7.3 ± 3.7, p = 0.041) were also decreased after biophysical treatment compared to placebo after one month. Our findings suggest that biophysical therapy can benefit workers with mild (subclinical) anxiety/stress. These results were also validated by the concomitant reduction of SAA levels and an improvement in DASS-21 subscales. The underlying molecular mechanisms of this therapy remain to be characterized.

When Is Hope Enough? Hopefulness, Discrimination and Racial/Ethnic Disparities in Allostatic Load

Hopefulness is associated with better health and may be integral for stress adaptation and resilience. Limited research has prospectively examined whether hopefulness protects against physiological dysregulation or does so similarly for U.S. whites, blacks and Hispanics. We examined the association between baseline hopefulness and future allostatic load using data from the Health and Retirement Study (n = 8,486) and assessed differences in this association by race/ethnicity and experiences of discrimination. Four items measured hopefulness and allostatic load was a count of seven biomarkers for which a respondent's measured value was considered high-risk for disease. A dichotomous variable assessed whether respondents experienced at least one major act of discrimination in their lifetime. We used Poisson regression to examine the association between hopefulness and allostatic load and included a multiplicative interaction term to test racial/ethnic differences in this association. Subsequent analyses were stratified by race/ethnicity and tested the interaction between hopefulness and discrimination within each racial/ethnic group. Hopefulness was associated with lower allostatic load scores, but its effects varied significantly by race/ethnicity. Race-stratified analyses suggested that hopefulness was protective among whites and not associated with allostatic load among Hispanics irrespective of experiencing discrimination. Hopefulness was associated with lower allostatic load among blacks reporting discrimination but associated with higher allostatic load among those who did not. Findings suggest that hopefulness plays differing roles for older whites, blacks and Hispanics and, for blacks, its protective effects on physiological dysregulation are intricately tied to their experiences of discrimination.