Allostatic load in early pregnancy and sleep-disordered breathing

OBJECTIVES

To assess the association between allostatic load in early pregnancy and sleep-disordered breathing (SDB) during pregnancy.

METHODS

High allostatic load in the first trimester was defined as ≥ 4 of 12 biomarkers (systolic blood pressure, diastolic blood pressure, body mass index, cholesterol, low-density lipoprotein, high-density lipoprotein, high sensitivity C-reactive protein, triglycerides, insulin, glucose, creatinine, and albumin) in the unfavorable quartile. SDB was objectively measured using the Embletta-Gold device and operationalized as "SDB ever" in early (6-15 weeks) or mid-pregnancy (22-31 weeks); SDB at each time point was analyzed as secondary outcomes. Multivariable logistic regression was used to test the association between high allostatic load and SDB, adjusted for confounders. Moderation and sensitivity analyses were conducted to assess the role of allostatic load in racial disparities of SDB and obesity affected the relationship between allostatic load and SDB.

RESULTS

High allostatic load was present in 35.0% of the nuMoM2b cohort. The prevalence of SDB ever occurred among 8.3% during pregnancy. After adjustment, allostatic load remained significantly associated with SDB ever (aOR= 5.3; 3.6-7.9), in early-pregnancy (aOR= 7.0; 3.8-12.8), and in mid-pregnancy (aOR= 5.8; 3.7-9.1). The association between allostatic load and SDB was not significantly different for people with and without obesity. After excluding BMI from the allostatic load score, the association decreased in magnitude (aOR= 2.6; 1.8-3.9).

CONCLUSION

The association between allostatic load and SDB was independent of confounders including BMI. The complex and likely bidirectional relationship between chronic stress and SDB deserves further study in reducing SDB.

Impact of baseline and longitudinal allostatic load changes on incident cardiovascular disease and all-cause mortality: A 7-year population-based cohort study in China

BACKGROUND

We aimed to prospectively examine the association of baseline allostatic load (AL) and longitudinal AL changes with incident cardiovascular disease (CVD) and all-cause mortality among middle-aged and elderly Chinese populations and evaluate the relative contributions of each physiological system of AL.

METHODS

Data from the China Health and Retirement Longitudinal Study (CHARLS) among adults aged 45 years or older were analyzed. Cox regression models were used to estimate the hazard ratios (HRs) and 95 % confidence intervals (95 % CIs) for the associations between baseline AL/longitudinal AL changes with incident CVD and all-cause mortality.

RESULTS

Compared with adults with AL 0-1, HRs of those with baseline AL 2-3 and AL ≥ 4 were 1.24 (95 % CI: 1.06, 1.45) and 1.51 (95 % CI: 1.27, 1.80) for incident CVD, and 1.39 (95 % CI: 1.11, 1.75) and 2.02 (95 % CI: 1.60, 2.54) for all-cause mortality. Similar results were found when we treated baseline AL as a continuous variable. We also found per AL score increase during 4 years of follow-up was related to a 11 % (HR, 1.11; 95 % CI: 1.03, 1.20) and 21 % (HR, 1.21; 95 % CI: 1.10, 1.34) increase in incident CVD and all-cause mortality, respectively.

LIMITATIONS

Self-reported physician-diagnosed CVD was used to assess the incident CVD.

CONCLUSIONS

Both baseline AL and longitudinal increases in AL were positively associated with incident CVD and all-cause mortality in middle-aged and elderly adults. Individuals with high AL need to be dynamically monitored for CVD and pre-mature mortality prevention.

Accumulating burden: Exposure to interpersonal discrimination based on multiple attributes and allostatic load

Exposure to interpersonal discrimination is an acute type of social stressor. Extant evidence suggests a positive association exists between experiencing interpersonal discrimination and physiological dysregulation measured by allostatic load. However, research to date has overlooked the role of exposure to interpersonal discrimination based on multiple attributes. This is an important oversight because individuals who confront discrimination often accredit the experiences to more than one attribute, which may be associated with increased stress and adverse physiological functioning. Using data from the Wave V biomarker subsample of the National Longitudinal Study of Adolescent to Adult Health (Add Health), I investigate the relationship between reports of interpersonal discrimination based on multiple attributes and allostatic load among adults ages 33-44. I also consider the roles of frequency of exposure to discrimination and perceived stress in this relationship through moderation and mediation analyses. Results reveal a positive association between the number of forms of discrimination that individuals report and allostatic load. However, frequency of exposure to discrimination does not moderate this association. Moreover, frequency of discrimination did not mediate the association between the number of forms of discrimination and perceived stress only marginally mediated it. This study offers novel and important insight into the role of exposure to more than one form of discrimination and allostatic load. Given that heightened allostatic load is a precursor to the development of chronic conditions and a strong risk factor for mortality, efforts to reduce discrimination among Americans adults will work to improve physical health.

Biomarker Profiles of Depression During Young Adulthood: Results From the National Health and Nutrition Examination Survey

PURPOSE

Cumulative "wear and tear" on physiological systems (allostatic load) may contribute to risk for depression, but there is limited research on allostatic load during young adulthood, which is a peak developmental period for depression onset. This study evaluates profiles of allostatic load and their association with depression in young adults.

METHODS

Biomarker and depression data were extracted for 18-24-year-olds (928 females, 932 males) in the National Health and Nutrition Examination Survey from 2015 to 2020. Latent class analysis was used to identify biomarker profiles. Multivariate logistic regression analyses were used to predict depression based on profile membership, controlling for sociodemographic characteristics.

RESULTS

Three allostatic load profiles were identified in both females and males-high inflammatory and moderate metabolic dysregulation (immunometabolic dysregulation), high metabolic and moderate inflammatory dysregulation (metaboimmune dysregulation), or low dysregulation. Metaboimmune or immunometabolic dysregulation profiles in females, and metaboimmune dysregulation in males, were associated with 3-3.5 times greater odds of depression compared to low dysregulation profiles.

DISCUSSION

Profiles of immune and metabolic dysregulation can be observed during young adulthood. Elevated immunometabolic and metaboimmune profiles were associated with depression risk in young adult females, while elevated metaboimmune profiles were associated with depression risk in young adult males. Detection of depression-related physiological dysregulation in young adults could be used to identify depression phenotypes and apply early interventions.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Correlation of allostatic load and perceived stress with clinical features in first-episode schizophrenia

BACKGROUND

Stress plays an important role in the etiology of schizophrenia. However, the mechanisms by which chronic physiological stress and perceived stress relate to the clinical features of schizophrenia may differ. We aimed to elucidate the relationships among chronic physiological stress indexed by allostatic load (AL), perceived stress, and clinical symptoms in individuals with first-episode schizophrenia (FES).

METHODS

Individuals with FES (n = 90, mean age = 28.26years old, 49%female) and healthy controls (111, 28.88, 51%) were recruited. We collected data of 13 biological indicators to calculate the AL index, assessed subjective stress with the Perceived Stress Scale-14 (PSS-14), and compared AL and perceived stress between groups. Patients with FES were also evaluated with the Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS).

RESULTS

Individuals with FES had higher AL and PSS score than healthy controls. There were no significant correlations between AL and PSS score in either patients or controls. Among individuals with FES, the AL index was associated with the severity of positive symptoms, while the PSS score was positively associated with CDSS score. Both elevated AL and PSS were correlated with the occurrence of schizophrenia.

CONCLUSIONS

Physiological stress, as reflected by AL, may be more related to positive symptoms, while perceived stress appear to be associated with depressive symptoms in individuals with FES. Longitudinal studies are necessary to explore the relationships between interventions for different stressor types and specific clinical outcomes in FES.

Long-term Neighborhood Poverty Effects on Internalizing Symptoms in Adolescents: Mediated Through Allostatic Load and Pubertal Timing

PURPOSE

The long-term effect of neighborhood poverty on internalizing symptoms in adolescents and the biological mechanisms underlying this association remain unclear. We defined neighborhood poverty at the village level in two dimensions: intensity (i.e., poverty rate) and duration. This study investigated how the poverty rate and duration of exposure to neighborhood poverty interact to predict internalizing symptoms in adolescents through biological mechanisms (i.e., allostatic load and early pubertal timing).

METHODS

A total of 418 adolescents (50.2% girls; 11-14 years old; mean age = 12.57 years) living in rural China participated in two waves of data collection. Path analysis was conducted to examine the mediating role of allostatic load and pubertal timing in the relationship between the duration of exposure to neighborhood poverty and internalizing symptoms. Moreover, the interactive effect between the poverty rate and duration of neighborhood poverty on the allostatic load was tested.

RESULTS

The positive association between the duration of exposure to neighborhood poverty and internalizing symptoms of adolescents was explained by elevated allostatic load and early pubertal timing after adjusting for gender, age, prior family socioeconomic states and internalizing symptoms. The duration in neighborhood poverty was a stronger predictor of allostatic load for adolescents living in high poverty rate neighborhoods than for those living in low poverty rate neighborhoods.

DISCUSSION

Neighborhood poverty gets "under the skin" through biological pathways and affects internalizing symptoms among adolescents. The findings highlight the importance of considering different dimensions of neighborhood poverty (e.g., intensity and duration) on adolescents' health.

Associations of allostatic load with sociodemographic factors, depressive symptoms, lifestyle, and health characteristics in a large general population-based sample

OBJECTIVE

We examined the associations between allostatic load (AL) and sociodemographic factors, depressive symptoms, lifestyle and health characteristics in a population-based sample of 4993 adults in Finland.

METHODS

Thirteen biomarkers were used to construct AL. High AL was defined as scoring highly in ≥4 items.

RESULTS

AL scores of 4 and above were exceeded in the age group of 45-54 years in men and 65-74 years in women. Age was the strongest predictor for belonging to the high AL score group. In addition, elevated depressive symptoms (BDI-6 ≥ 4), male sex, not engaging in physical exercise, high alcohol use and a low level of education were associated with an increased likelihood of belonging to the high AL group.

CONCLUSION

The older the participants were, the greater their AL burden was. However, AL burden increased more steeply as a function of age in men. In addition to lifestyle interventions, effective prevention strategies for depression at the population level could have a major public health impact in reducing the accumulation of AL burden.

Variation and correlates of psychosocial wellbeing among nulliparous women with preeclampsia

OBJECTIVES

To identify classes of psychosocial stressors among women who developed preeclampsia and to evaluate the associations between these classes and correlates of psychosocial wellbeing.

STUDY DESIGN

We performed a secondary analysis of women who developed preeclampsia (n = 727) from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMoM2b) cohort (2010-2013). Latent class analysis was used to identify classes of social stressors based on seven psychological and sociocultural indicators. Associations between latent classes and correlates (demographics, health behavior, and health-systems level) were estimated using multinomial logistic regression.

MAIN OUTCOME MEASURES

Classes of psychosocial wellbeing.

RESULTS

Among women who developed preeclampsia, three classes reflective of psychosocial wellbeing were identified: Class 1: Intermediate Psychosocial Wellbeing (53 %), Class 2: Positive Psychosocial Wellbeing (31 %), Class 3: Negative Psychosocial Wellbeing (16 %). Women in the Negative Psychosocial Wellbeing Class were more likely to have poor sleep and a sedentary lifestyle compared with the Positive and Intermediate Psychosocial Wellbeing Classes. Both the Negative and Intermediate Psychosocial Wellbeing Classes reported concern about their quality of medical care compared with the Positive Psychosocial Wellbeing Class (adjusted odds ratio [aOR]: 6.19, 95 % confidence interval [CI]: 3.37, 11.36 and aOR: 2.19, 95 % CI: 1.31, 3.65, respectively).

CONCLUSIONS

Women who develop preeclampsia are heterogenous and experience different intensities of internal and external stressors. Understanding the linkages between psychosocial wellbeing during pregnancy and modifiable behavioral and structural factors may inform future tailored management strategies for preeclampsia and the optimization of maternal postpartum health.

Does it add up? Educational achievement mediates child maltreatment subtypes to allostatic load

BACKGROUND

Childhood maltreatment (CM) has been linked to higher levels of allostatic load (AL) and educational achievement is a possible pathway and may differ across gender. It is also critical to determine if CM severity or specific subtypes of CM are more or less influential.

OBJECTIVE

This study examined educational achievement as a mediator linking cumulative and individual types of CM to AL and examined gender as a moderator.

PARTICIPANTS AND SETTING

Using two waves of data, 897 adults from the study Midlife in the United States were analyzed.

METHODS

Multiple group structural equation models stratified across gender to test were used cumulative maltreatment and maltreatment subtypes to AL and test gender as a moderator.

RESULTS

Overall CM was associated with educational achievement (β = -0.12, p < .01) and AL (β = 0.11, p < .05) and education was inversely associated with AL (β = -0.17, p < .001) in men but not women. The subtypes model revealed that physical abuse predicted lower level of education achievement (β = -0.20, p < .001) and among men. Educational achievement, in turn, was associated with lower levels of AL (β = -0.02, p = .002). Educational achievement was a possible pathway linking physical abuse to AL (β = 0.02, 95 % CI [0.001, 0.040]) among men but was non-significant in women. Gender did not moderate any of the pathways.

CONCLUSIONS

Educational achievement is a potentially modifiable social determinant of health that can be a focus of prevention and intervention efforts among men who were maltreated, particularly for those who experienced physical abuse.

Time outdoors and residential greenness are associated with reduced systemic inflammation and allostatic load

Contacts with nature are linked with reduced morbidity and mortality. Hypothesized pathways include relaxation, physical activity, and improved immune function. This cross-sectional study of 320 adults in central North Carolina assessed health benefits of residential greenness using allostatic load (AL) and systemic inflammation (INFL) indices, composite biomarker-based measures of physiological dysregulation and inflammation, respectively. Distance-to-residence weighted tree cover and vegetated land cover measures were estimated within 500 m of each residence; 37 biomarkers of immune, neuroendocrine, cardiovascular, and metabolic functions were dichotomized at distribution or health-based cut-offs. AL was calculated as a sum of potentially unhealthy values of all biomarkers; INFL was based on a subset of 18 immune biomarkers. Regression analysis used generalized additive models for Poisson-distributed outcome. An interquartile range (IQR) increase in tree cover was associated with 0.89 (95 % Confidence Limits 0.82; 0.97) and 0.90 (0.79; 1.03)-fold change in AL and INFL, respectively. Greater daily outdoor time was associated with reduced AL and INFL, while leisure screen time, problems with sleeping, and common chronic infections were linked with increased AL and INFL. Among 138 individuals spending more than 1 h outdoors daily, an IQR increase in tree cover was associated with 0.76 (0.67; 0.86) and 0.81 (0.65; 1.02)-fold changes in AL and INFL, respectively. Among individuals with residential tree cover above the 50th percentile, spending more than 3 h outdoors daily was associated with 0.54 (0.37; 0.78) and 0.28 (0.15; 0.54)-fold changes in AL and INFL, respectively, compared to spending less than 30 min outdoors; there were no significant effects in the low tree cover stratum. Consistent but weaker effects were observed for vegetated land cover. Interaction effects of tree and vegetative cover and time spent outdoors on AL and INFL were statistically significant. This biomarker-based approach can help to assess public health benefits of green spaces.

Allostatic load and chronic pain: a prospective finding from the national survey of midlife development in the United States, 2004-2014

BACKGROUND

Previous research has demonstrated a correlation between chronic stress and chronic pain (CP). However, there have been few studies examining the prospective association of allostatic load (AL)-the biological processes related to stress-with CP.

METHODS

We firstly conducted latent class analysis to identify phenotypes of AL using a community-dwelling sample, the Midlife in the United States. Multinomial logistic regression models were used to examine the prospective association between phenotypes of AL at MIDUS 2 biomarker project and the presence of CP, CP interference and the number of CP sites at MIDUS 3.

RESULTS

Three phenotypes of AL, low biological dysregulation, parasympathetic dysregulation and metabolic dysregulation, were identified. Compared to low biological dysregulation group, participants experiencing metabolic dysregulation phenotype of AL at MIDUS 2 had higher risks of having high-interference CP (RRR = 2.00, 95% CI: 1.06, 3.79, P < 0.05) and 3 or more CP sites (RRR = 2.03, 95% CI: 1.08, 3.83, P < 0.05) at MIDUS 3.

CONCLUSION

The findings indicate that focusing on mitigating the metabolic dysfunction phenotype of AL has the potential to be an efficacious strategy for alleviating future CP bodily widespreadness and high CP interference.

Allostatic Load as a Predictor of Postoperative Complications in Patients with Breast Cancer

BACKGROUND

Allostatic load (AL) is a biological measure of cumulative exposure to socioenvironmental stressors (e.g., poverty). This study aims to examine the association between allostatic load (AL) and postoperative complications (POC) among patients with breast cancer.

METHODS

Assigned females at birth ages 18 + with stage I-III breast cancer who received surgical management between 01/01/2012-12/31/2020 were identified in the Ohio State Cancer registry. The composite AL measure included biomarkers from the cardiovascular, metabolic, immune, and renal systems. High AL was defined as composite scores greater than the cohort's median (2.0). POC within 30 days of surgery were examined. Univariable and multivariable regression analysis examined the association between AL and POC.

RESULTS

Among 4,459 patients, 8.2% had POC. A higher percentage of patients with POC were unpartnered (POC 44.7% vs no POC 35.5%), government-insured (POC 48.2% vs no POC 38.3%) and had multiple comorbidities (POC 32% vs no POC 20%). Patients who developed POC were more likely to have undergone sentinel lymph node biopsy followed by axillary lymph node dissection (POC 51.2% vs no POC 44.6%). High AL was associated with 29% higher odds of POC (aOR 1.29, 95% CI 1.01-1.63). A one-point increase in AL was associated with 8% higher odds of POC (aOR 1.08, 95% CI 1.02-1.16) and a quartile increase in AL was associated with 13% increased odds of POC (aOR 1.13, 95% CI 1.01-1.26).

CONCLUSION

Among patients undergoing breast cancer surgery, increased exposure to adverse socioenvironmental stressors, operationalized as AL, was associated with higher odds of postoperative complications.

Effort-reward and overcommitment at work and psychiatric symptoms in healthcare professionals: The mediation role of allostatic load

Background

Despite decades of advancement to support interventions for managing work-related stress, mental health issues have significantly escalated among healthcare professionals. Effort-reward imbalance (ERI) and overcommitment in the workplace are linked to several psychiatric disorders. However, the underlying biological mechanisms remain unclear. This study investigated whether ERI and overcommitment among healthcare professionals were linked to Allostatic Load (AL) and whether AL mediates the relationship between ERI, overcommitment and mental health issues.

Methods

One hundred forty-two nursing workers (n = 142; 90.1 % female, mean age: 39.5 ± 9.6) were randomly recruited from a university hospital in Sao Paulo, Brazil, and applied the ERI scale that assesses work effort, reward, and overcommitment. The Perceived Stress Scale (PSS), The Beck Depression Inventory (BDI), and the Self-Report Questionnaire for psychiatric symptoms (SRQ-20) evaluated the mental health outcomes. Ten neuroendocrine, metabolic, immunologic and cardiovascular biomarkers were analyzed, and values were transformed into an AL index using clinical reference cutoffs.

Results

Linear regression adjusted for covariates showed that higher scores for overcommitment were associated with higher AL indexes, which in turn were associated with higher SRQ-20, but not with PSS and DBI scores. As expected, higher scores for effort, lower for reward, and higher ERI were associated with higher scores for PSS, SRQ-20, and DBI, but not with AL index. Direct effect estimates showed that overcommitment was directly associated with higher SRQ-20 scores, and indirectly via AL.

Conclusion

Our study reveals that overcommitment, rather than ERI, was linked to increased AL in healthcare workers. Additionally, AL mediates the relationship between overcommitment and higher psychiatric symptoms, highlighting a key mechanism by which work stress can lead to mental health problems. Individual's responses to high work demands need to be considered when designing predictive models and interventions for mental health issues.

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.

The interrelationships of hearing function, allostatic load, and cognitive function: Evidence among middle-aged and older Chinese adults

OBJECTIVES

We aim to examine the interrelationships of self-reported hearing function, allostatic load (AL), and cognitive function among middle aged and older adults.

METHODS

Our data were collected from two waves of the China Health and Retirement Longitudinal Study (CHARLS) conducted in 2011 and 2015. The participants' hearing function was measured using self-rated subjective hearing function. Allostatic load (AL) was evaluated by measuring 14 biomarkers associated with physiological health, which were derived from blood samples. Cognitive function was assessed using three domains: episodic memory, mental intactness, and global cognition. To examine the relationships between hearing function, AL, and cognitive function, path analysis with structural equation modeling (SEM) methodology was employed.

RESULTS

Among individuals aged 60 and above non-hearing aids users, the hearing function at Time 1 (T1) in 2011 has a significant association with the level of AL at T1 (β = 0.02, p < 0.001), as well as on cognitive function at Time 2 (T2) in 2015 (β = -0.1, p < 0.001). Additionally, the AL related to the hearing function at T1 associates an increased risk of AL at T2 (β = 0.5, p < 0.001), and is significantly associated with a decrease of cognitive function scores at T2 (β = -0.4, p < 0.001). However, no significant relationship was found among individuals aged 45 - 59 with non-hearing aids utilizers. Similar findings were in the domains of epidemic memory and mental intactness for cognitive function.

CONCLUSIONS

There were interrelationships of subjective hearing function, AL, and cognitive function among aged 60 years and above, but not among those aged 45-59 years old. It may provide valuable insights for identifying subclinical thresholds in the physiological systems of individuals at risk of pathology in cognitive function.

Mind versus body: Perceived stress and biological stress are independently related to cognitive decline

Chronic stress may increase risk of age-related cognitive decline. 'Stress', however, is a multidimensional construct and few studies have investigated the inter-relationship of subjective stress and biological stress with cognitive decline. In this study, we examine the relationship between perceived stress and two measures of biological stress - allostatic load, indexing stress at the physiological level and leukocyte telomere length, indexing stress at the cellular level - with cognitive decline over a 12-year period in adults aged 50 and older. 3,458 participants (aged ≥ 50) from The Irish Longitudinal study on Ageing with measurements of allostatic load, telomere length and perceived stress at baseline and repeated measures of cognitive function were included. Hierarchical linear regression models with adjustment for multiple potential confounders were applied, and repeated stratified by sex in sensitivity analyses. Higher perceived stress at baseline was associated with lower cognitive function (β = -0.10, 95 % CI -0.12, -0.07, p <.001), with similar strength of associations across waves. There were significant interactions between measures of biological stress and wave; higher allostatic load was associated (X2(18) = 64.4; p <.001), and telomere length was borderline (X2(18) = 9.4; p =.09) associated with cognitive decline from 4-year follow-up onward. Sex stratified analyses revealed that the association between telomere length and cognitive decline was present in women only. Mutual adjustment did not attenuate associations in either case. The interactions between allostatic load and telomere length with perceived stress were not significant. Our findings suggest that subjective measures of stress and biological metrics may be independently related to cognitive function over time in older adults, hinting at the potential for different underlying mechanisms.

Allostatic load and risk of invasive breast cancer among postmenopausal women in the U.S

OBJECTIVE

Allostatic load can reflect the body's response to chronic stress. However, little is known about the association between allostatic load and risk of breast cancer in postmenopausal women. This study used a large prospective cohort in the United States to examine the relationship between allostatic load and invasive breast cancer risk, and to evaluate the relationship by racial and ethnic identity and breast cancer subtypes.

METHODS

Among 161,808 postmenopausal participants in Women's Health Initiative, eligible were a subsample of 27,393 postmenopausal women aged 50-79 years old, who enrolled from 1993 to 1998, had serum test biomarkers, and were followed for breast cancer incidence through February 2022. Allostatic load at enrollment was computed based on eight biomarkers from lab serum tests and a questionnaire about participants' prescription drug use. The associations between allostatic scores and risk of breast cancer (overall and by subtypes) were assessed using Cox proportional hazards models. The race and ethnic differences were examined.

RESULTS

Over a median follow-up time of 17.24 years, 1722 invasive breast cancer cases were identified. High allostatic load was associated with an increased risk of breast cancer (HR = 1.36, 95%CI: 1.20, 1.54 for third tertile vs first tertile, Ptrend < 0.0001). Similar trends were found in White women and non-Hispanic women. Higher allostatic load was associated with hormone receptor-positive and HER2/Neu-negative breast cancer (HR = 1.54, 95%CI: 1.30, 1.80 for third tertile vs first tertile, Ptrend < 0.0001).

CONCLUSION

In this study, we found that higher allostatic load was significantly associated with an increased risk of breast cancer in postmenopausal women.

Interpersonal touch and the importance of romantic partners for older adults' neuroendocrine health

Interpersonal touch is an essential aspect of human interaction that has the ability to regulate physiological stress responses. Prolonged exposure to stress can have cumulative multiphysiological effects; for example, allostatic load. Despite the increased susceptibility of social isolation for older adults, there is a paucity of research on the efficacy of touch in regulating stress responses among this population. It is also unknown whether touch confers benefits regardless of the person with whom it is shared. This study investigates the difference in physiological stress based on the frequency of touch (hugs, holding, or other close physical contact) shared with romantic partners as compared to other close adults (family, friends, and neighbours) in an older adult population. Data were analysed from 1419 respondents (aged 57-85 years) of the National Social Life, Health, and Aging Project (NSHAP) in 2005-2006. Principal components analysis determined whether the eight markers of allostatic load measured in the NSHAP function as a singular system or as distinct components. Analyses revealed three components of allostatic load: metabolic, cardiovascular, and neuroendocrine health. The results of multiple regression revealed that a higher frequency of interpersonal touch shared with romantic partners was associated with better neuroendocrine health (β = 0.13, p = 0.004) following adjustment for a variety of covariates (but not with better metabolic or cardiovascular health), with no associations apparent for touch from other close adults. These findings highlight the importance of promoting interpersonal touch with romantic partners for older adults' neuroendocrine health.

Evidence for an association between allostatic load and multisensory integration in middle-aged and older adults

Multisensory integration, the ability of the brain to integrate information from different sensory modalities, is critical for responding to environmental stimuli. While older adults show changes in multisensory integration with age, the impact of allostatic load (AL) (i.e., the effect of exposure to chronic stress, which can accelerate ageing) on multisensory perception remains understudied. We explored the relationship between multisensory integration and AL in 1,358 adults aged 50+ from The Irish Longitudinal Study on Ageing by performing a Sound Induced Flash Illusion (SIFI) task at multiple audio-visual temporal asynchronies. The AL score was created using a battery of biomarkers representing the activity of four major physiological systems: immunological, cardiovascular, metabolic, and renal. The number of biomarkers for which a participant was categorised in the highest risk quartile using sex-specific cutoffs was used to produce an overall AL score. We accounted for medication use when calculating our AL score. We analysed the accuracy of illusion trials on a SIFI task using generalised logistic mixed effects regression models adjusted for a number of covariates. Observation of cross-sectional and longitudinal results revealed that lower accuracy in integration (i.e., higher SIFI susceptibility with larger temporal asynchronies) was associated with higher AL. This confirmed the distinct patterns of multisensory integration in ageing.

Association between allostatic load and breast cancer risk: a cohort study

BACKGROUND

Allostatic load (AL) reflects the collective load of chronic stress during lifetime. Previous studies have shown that higher AL is associated with poor clinical outcomes among breast cancer patients. However, the relationship between AL and breast cancer risk is still unclear.

METHODS

To fill the gap, we analyzed the association between AL and the development of breast cancer in 181,455 women identified from the UK Biobank.

RESULTS

During the follow-up from 2006 to 2020, 5,701 women were diagnosed with incident breast cancer. Significantly higher AL was observed among incident breast cancer cases than all study participants (mean: 2.77 vs. 2.63, P < 0.01). Univariate Cox regression analysis indicated the risk of breast cancer was increased by 5% per one AL unit increase (hazard ratio (HR) = 1.05, 95% confidence interval (CI) 1.04, 1.07). In multivariate analyses, after adjusting demographics, family history of breast cancer, reproductive factors, socioeconomic status, lifestyle factors, and breast cancer polygenic risk score (PRS), the significant association remained (HR = 1.05, 95%CI 1.03, 1.07). The significant relationship was further confirmed in the categorical analysis. Compared with women in the low AL group (AL: 0 ~ 2), those in the high AL group (AL: 3 ~ 11) had a 1.17-fold increased risk of breast cancer (HR = 1.17, 95%CI 1.11, 1.24). Finally, in the stratified analysis, joint effects on the risk of breast cancer were observed between the AL and selected known breast cancer risk factors, including age, family history of breast cancer, PRS, income, physical activity, and alcohol consumption.

CONCLUSION

In summary, those findings have demonstrated that higher AL was associated with an increased breast cancer risk in women. This association is likely independent of known breast cancer risk factors. Thus, the AL could be a valuable biomarker to help breast cancer risk prediction and stratification.

Allostatic load in the US general population: Race and educational intersection

Objectives

Educational attainment is a protective factor against poor health, but high educational attainment has a weaker effect on black people than on white people; this pattern has been called marginalization-related diminished returns (MDRs). Using a national sample of white people and black people 25 years and above, this study estimates the association between high educational attainment and allostatic load between black people and white people, and within each group.

Study design

This cross-sectional study uses data from the National Health and Nutrition Examination Survey (NHANES) between 1999 and 2016, including 2761 black people and 7058 white people. The outcome variable of interest was the Allostatic Load Scale (AL). We created the allostatic load scale by using 8 biomarkers, then created a binary variable (if ALS≥4 as 1 and ALS<4 as 0) to present elevated AL.

Methods

We used several weighted modified Poisson regression models controlling for educational attainment (a predictor) and race (a moderator variable), age, sex, and marital status. We also controlled the models for smoking and drinking status as health behavior variables. As a sensitivity analysis, we ran several sets of regression analysis using the AL scale as a continuous outcome variable.

Results

We found an inverse association between AL and educational attainment. The interaction between race and education has resulted in an inverse association between AL and educational attainment, with a weaker association in black people than in white people. We found similar findings by running regression models with AL as a continuous variable.

Conclusions

We observed a weaker association between educational attainment and AL in black people than in white people, suggesting that educational attainment has more robust protection against allostatic load for white people than black people.

The Social Context: Social and Behavioral Factors That Affect Health Outcomes

To achieve understanding and best care, screening and treating patients should consider the patient's social environment. Social and behavioral factors influence both positive and negative health behaviors that influence mental and physical health. Primary care providers continually navigate barriers faced by patients and seek solutions that take into consideration social and behavioral factors. The role of the PCP begins with an understanding of common barriers and community resources, then by assessing and responding to the patient's own challenges, and finally by advocating in the clinic and public for changes to the underlying social and structural causes of morbidity and mortality.

Climate Change: The Ultimate Determinant of Health

Climate change ubiquitously influences social determinants of health via various pathways. Disproportionately burdening communities who have contributed the least to greenhouse gas (GHG) emissions and benefitted the least from economic benefits obtained through high-emission activities that cause climate change, climate justice must be centered in any discussion of health equity. This article will explore how climate change contributes to health disparities in vulnerable populations, why this is a justice issue for primary care to address, and what we can do to promote equity, resilience, and adaption in our current economic system while mitigating GHG emissions, leveraging the health sector.

Community health worker navigation to improve allostatic load: The Integrated Population Health (IPOP) study

Background

Social determinants of health (SDOH) and cumulative stress contribute to chronic disease development. The physiological response to repeated stressors typical of lower-income environments can be measured through allostatic load - a composite measure of cardiovascular, metabolic, and immune variables. Healthcare systems have employed patient navigation for social and medical needs to improve SDOH that has demonstrated limited impact on chronic disease outcomes. This study evaluates a novel community health worker navigation intervention developed using behavioral theories to improve access to social and medical services and provide social support for poverty stressed adults.

Methods

The Integrated Population Health Study (IPOP) study is a randomized, parallel two arm study evaluating community health worker navigation in addition to an existing integrated population health program (IPOP CHW) as compared to Usual Care (population health program only, IPOP) on allostatic load and chronic disease risk factors. IPOP CHW participants receive a 10-month navigation intervention.

Results

From 381 screened individuals, a total of 202 participants (age 58.15 ± 12.03 years, 74.75 % female, 79.21 % Black/African American, 17.33 % Hispanic) were enrolled and randomized to IPOP CHW (n = 100) or IPOP Only (n = 102).

Conclusion

This study will evaluate whether CHW navigation, using a structured intervention based on health behavior theories, can effectively guide poverty stressed individuals to address social and medical needs to improve allostatic load-a composite of cumulative stress and physiological responses. Healthcare systems, nonprofit organizations, and governmental entities are interested in addressing SDOH to improve health, thus developing evidence-based interventions could have broad clinical and policy implications.

Relationship of Morphometrics and Symptom Severity in Female Type I Chiari Malformation Patients with Biological Resilience

In the present study we report the relationship among MRI-based skull and cervical spine morphometric measures as well as symptom severity (disability-as measured by Oswestry Head and Neck Pain Scale and social isolation-as measured by the UCLA Loneliness scale) on biomarkers of allostatic load using estrogen, interleukin-6, C-reactive protein, and cortisol in a sample of 46 CMI patients. Correlational analyses showed that McRae line length was negatively associated with interleukin-6 and C-reactive protein levels, and Analysis of Variance (ANOVA) showed joint effects of morphometric measures (McRae line length, anterior CSF space) and symptom severity (disability and loneliness) on estrogen and intereukin-6 levels. These results are consistent with allostatic load. That is, when the combination of CSF crowding and self-report symptom (disability and loneliness) severity exceed the capacity of biological resilience factors, then biomarkers such as neuroprotective estrogen levels drop, rather than rise, with increasing symptom severity.

Elucidating individual differences in chronic pain and whole person health with allostatic load biomarkers

Chronic pain is a stressor that affects whole person functioning. Persistent and prolonged activation of the body's stress systems without adequate recovery can result in measurable physiological and neurobiological dysregulation recognized as allostatic load. We and others have shown chronic pain is associated with measures of allostatic load including clinical biomarker composites, telomere length, and brain structures. Less is known regarding how different measures of allostatic load align. The purpose of the study was to evaluate relationships among two measures of allostatic load: a clinical composite and pain-related brain structures, pain, function, and socioenvironmental measures. Participants were non-Hispanic black and non-Hispanic white community-dwelling adults between 45 and 85 years old with knee pain. Data were from a brain MRI, questionnaires specific to pain, physical and psychosocial function, and a blood draw. Individuals with all measures for the clinical composite were included in the analysis (n = 175). Indicating higher allostatic load, higher levels of the clinical composite were associated with thinner insula cortices with trends for thinner inferior temporal lobes and dorsolateral prefrontal cortices (DLPFC). Higher allostatic load as measured by the clinical composite was associated with greater knee osteoarthritis pathology, pain disability, and lower physical function. Lower allostatic load as indicated by thicker insula cortices was associated with higher income and education, and greater physical functioning. Thicker insula and DLPFC were associated with a lower chronic pain stage. Multiple linear regression models with pain and socioenvironmental measures as the predictors were significant for the clinical composite, insular, and inferior temporal lobes. We replicate our previously reported bilateral temporal lobe group difference pattern and show that individuals with high chronic pain stage and greater socioenvironmental risk have a higher allostatic load as measured by the clinical composite compared to those individuals with high chronic pain stage and greater socioenvironmental buffers. Although brain structure differences are shown in individuals with chronic pain, brain MRIs are not yet clinically applicable. Our findings suggest that a clinical composite measure of allostatic load may help identify individuals with chronic pain who have biological vulnerabilities which increase the risk for poor health outcomes.

The association of allostasis with alcohol use: A case-control study in males with and without alcohol use disorder

BACKGROUND

Allostatic load (AL) is associated with a heightened predisposition to disease due to prolonged activation of biological stress-response systems. Alcohol use disorder (AUD) is known to activate these systems. The primary aim of the current study was to examine the relationship between AL and AUD.

METHODS

Participants were males (100%) with DSM-IV Alcohol Dependence (n = 48) and healthy participants with no history of substance use disorder (n = 17). Participants with AUD were 4-6 weeks abstinent. The AL index used cortisol, interleukin-6 (IL-6), fibrinogen, tumor necrosis factor-alpha (TNFα), C-reactive protein (CRP), glucose, insulin, leptin, pulse, systolic blood pressure readings, diastolic blood pressure readings, and body mass index (BMI). Physiological dysregulation for each biological measure was determined based on values within the 25th or 75th percentiles; AL was calculated as the total number of physiologically dysregulated biological measures.

RESULTS

No differences in mean AL scores between the cases and controls [t(63) = .48, p = .633] were observed. Among cases, AL was not associated with lifetime drinks per drinking day (F(2,42) = .42, p = .662), lifetime total drinks (F(2,42) = 0.48, p = .620), total drinks 6 months prior to participating in the study (F(2,43) = 0.58, p = .563), or drinks per drinking day at 3-month follow-up (F(2,35) = 1.93, p = .161). AL was negatively associated with drinks per drinking day 6 months prior to study participation (F(2,42) = 3.71, p = .033).

CONCLUSIONS

The hypotheses were not supported. Given that alcohol is likely to lead to physiological dysregulation, the apparent absence of a relationship between biomarkers of cumulative stress as indicated by AL and drinking status was both unanticipated and remarkable. Based on the results, AL in the context of drinking status or drinking among males with AUD may not be applicable.

Associations of Socioeconomic Factors and Unhealthy Lifestyles with Allostatic Load: A Meta-analysis

BACKGROUND

Allostatic load (AL) is a biological tool for objectively assessing chronic stress and has been discussed inconsistently for its correlation with socioeconomic factors and unhealthy lifestyles. Therefore, this meta-analysis was performed to explore the impact of socioeconomic factors and unhealthy lifestyles on AL.

METHOD

Different databases, including Web of Science, PubMed, EBSCOhost, Embase, CNKI, VIP, SinoMed, and Wanfang, were searched from inception to June 6, 2023. A total of 25 studies, reporting the correlations of seven socioeconomic factors and three unhealthy lifestyles with AL, were finally included. The pooled odds ratios (OR) and 95% confidence intervals (CIs) were examined using random-effect and fixed-effect models. Literature quality, heterogeneity, and publication bias were evaluated.

RESULTS

The meta-analysis showed a significantly increased risk of high AL in the older individuals as compared to the younger ones (OR = 1.05, 95% CI 1.04-1.06), in the individual with low education as compared to those with high education (OR = 1.25, 95% CI 1.05-1.48), and in the individuals with low physical activities as compared to those with high physical activities (OR = 1.44, 95% CI 1.26-1.64). This meta-analysis also showed a significantly decreased risk of high AL in the individuals with high income as compared to those with low income (OR = 0.77, 95% CI 0.71-0.83) and in women as compared to men (OR = 0.80, 95% CI 0.80-0.81).

CONCLUSION

This meta-analysis showed older people, men, and people having low physical activity, low income, and low education were more likely to have a high AL.

TRIAL REGISTRATION

This meta-analysis was registered on the PROSPERO database with trial registration number CRD42022326105. Instead of providing information at registration, we added an author (Tingyu Mu), who provided critical revisions to the paper in this meta-analysis.

Associations of prenatal and childhood Pb exposure with allostatic load in adolescence: Findings from the ELEMENT cohort study

The biological pathways which link lead (Pb) and long-term outcomes are unclear, though rodent models and a few human studies suggest Pb may alter the body's stress response systems, which over time, can elicit dysregulated stress responses with cumulative impacts. This study examined associations between prenatal and early childhood Pb exposure and adolescent allostatic load, an index of an individual's body burden of stress in multiple biological systems, and further examined sex-based associations. Among 391 (51% male) participants in the ELEMENT birth cohort, we related trimester-specific maternal blood Pb, 1-month postpartum maternal tibia and patella Pb, and child blood Pb at 12-24 months to an allostatic load index in adolescence comprised of biomarkers of cardiovascular, metabolic, neuroendocrine, and immune function. The results were overall mixed, with prenatal exposure, particularly maternal bone Pb, being positively associated with allostatic load, and early childhood Pb showing mixed results for males and females. In adjusted Poisson regression models, 1 mcg/g increase in tibia Pb was associated with a 1% change in expected allostatic load (IRR = 1.01; 95%CI 0.99, 1.02). We found a significant Pb × sex interaction (IRR = 1.05; 95%CI 1.01, 1.10); where males saw an increasing percent change in allostatic load as 12 month Pb levels increased compared to females who saw a decreasing allostatic load. Further examination of allostatic load will facilitate the determination of potential mechanistic pathways between developmental toxicant exposures and later-in-life cardiometabolic outcomes.

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

BACKGROUND

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

OBJECTIVE

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

PARTICIPANTS AND SETTING

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Sympathetic nervous system responses to acute psychosocial stress in male physicians with clinical burnout

BACKGROUND

Occupational burnout has been associated with an increased risk of cardiovascular disease, with sympathetic nervous system (SNS) dysfunction as one explanation. This study examined the effects of burnout on responses of SNS activity measures to acute psychosocial stress in male physicians, a population at risk for burnout.

METHODS

Study participants were 60 male physicians, 30 with clinical burnout, assessed with the Maslach Burnout Inventory, and 30 without burnout (controls). All participants underwent the 15-min Trier Social Stress Test. Heart rate, blood pressure, salivary alpha-amylase, and plasma levels of epinephrine (EPI) and norepinephrine were assessed pre-stress, immediately post-stress, and 15 min and 45 min post-stress.

RESULTS

Physicians with burnout and controls differed in EPI changes over time, controlling for age, job stress and anxiety symptoms (F (3,147) = 5.18, p = .002 for 'Time by Group' interaction; η2p = .096). Burnout was associated with a smaller increase in EPI from pre-stress to immediately post-stress (r(54) = -.40, p = .004). The emotional exhaustion dimension of burnout was a significant driver of this effect. The area under the curve with respect to increase in EPI was also smaller in the burnout group (F (1,49) = 6.06, p = .017, η2p = .110). Group differences were not significant for the other SNS activity measures.

CONCLUSIONS

Burnout may be linked to dysfunction of the sympathoadrenal medullary (SAM) system, when exposed to acute psychosocial stress. In keeping with the allostatic load concept, an insufficient SAM stress response in burnout could potentially contribute to cardiovascular disease.

The allostatic load model: a framework to understand the cumulative multi-system impact of work-related psychosocial stress exposure among firefighters

Firefighting is recognised as a profession where health and well-being can be affected by a variety of occupational factors, such as physical, thermal, and chemical stressors. Along with the risks intuitively associated with the fire service, however, psychosocial stress has begun to attract attention as another variable deserving of consideration. Indeed, long-term exposure to work-related psychosocial stress has been linked with poor health outcomes in many workers; however, despite this association, very little has been done to examine how such stressors become biologically embedded in firefighters. To help facilitate research into how psychosocial stress can affect health-related outcomes in the fire service, we propose a framework centered on the notion of allostatic load. First, we reviewed the occupational characteristics that may generate psychosocial stress within firefighters before introducing allostatic load (that is, dysregulation across various physiological systems caused by the need to manage ongoing stressors). Next, we provided a summary of how allostatic load can be measured and touched on the framework's utility for studying the cumulative effects of work-related stress on firefighter health. After this, factors that may influence the steps leading from stress exposure to health outcomes were discussed; in particular, we commented upon how research in this area should consider specific non-modifiable (age, sex, and ethnicity) and modifiable (psychosocial resources and behavioural habits) factors. Finally, we presented methodological barriers and opportunities that may arise when using the allostatic load framework with this professional group. By introducing the framework, we hope to provide a tool that may be used by those interested in stress-health research in firefighters to build the evidence needed to inform primary prevention measures.

Allostatic Load in Children and Adolescents: A Systematic Review

INTRODUCTION

The concept of allostatic load encompasses the cumulative effects of both ordinary daily life events as well as major challenges, and also includes related health-damaging behavior. Allostatic overload ensues when environmental challenges exceed the individual's ability to cope. Identification of allostatic load is carried out through the use of biomarkers and clinimetric criteria. Studies are increasingly reported on allostatic load in younger populations, yet a systematic review is missing.

OBJECTIVE

The aim of the present systematic review was to summarize the current knowledge on allostatic load/overload among children and adolescents.

METHODS

PubMed, PsycINFO, Web of Science, and the Cochrane Library were searched from inception to April 2023. A manual search of the literature was also performed. We considered only studies in which allostatic load or overload were adequately described and assessed in either clinical or non-clinical populations younger than 18 years.

RESULTS

A total of 38 original investigations were included in this systematic review. Studies reported an association between allostatic load and sociodemographic characteristics (e.g., poverty, ethnicity, perceived discrimination, adverse childhood experiences) and environmental factors, as well as consequences of allostatic load on both physical and mental health among children and adolescents.

CONCLUSIONS

The findings indicate that greater allostatic load is associated with poorer health outcomes in both clinical and non-clinical pediatric populations, with possible enduring effects. The results support the clinical utility of the transdiagnostic identification of allostatic load and overload in children and adolescents across a variety of settings, with a number of potential clinical implications.

Cellular allostatic load is linked to increased energy expenditure and accelerated biological aging

Stress triggers anticipatory physiological responses that promote survival, a phenomenon termed allostasis. However, the chronic activation of energy-dependent allostatic responses results in allostatic load, a dysregulated state that predicts functional decline, accelerates aging, and increases mortality in humans. The energetic cost and cellular basis for the damaging effects of allostatic load have not been defined. Here, by longitudinally profiling three unrelated primary human fibroblast lines across their lifespan, we find that chronic glucocorticoid exposure increases cellular energy expenditure by ∼60%, along with a metabolic shift from glycolysis to mitochondrial oxidative phosphorylation (OxPhos). This state of stress-induced hypermetabolism is linked to mtDNA instability, non-linearly affects age-related cytokines secretion, and accelerates cellular aging based on DNA methylation clocks, telomere shortening rate, and reduced lifespan. Pharmacologically normalizing OxPhos activity while further increasing energy expenditure exacerbates the accelerated aging phenotype, pointing to total energy expenditure as a potential driver of aging dynamics. Together, our findings define bioenergetic and multi-omic recalibrations of stress adaptation, underscoring increased energy expenditure and accelerated cellular aging as interrelated features of cellular allostatic load.

Investigating the association between educational attainment and allostatic load with risk of cancer mortality among African American women

BACKGROUND

African American (AA) women navigate the world with multiple intersecting marginalized identities. Accordingly, AA women have higher cumulative stress burden or allostatic load (AL) compared to other women. Studies suggest that AA women with a college degree or higher have lower AL than AA women with less than a high school diploma. We examined the joint effect of educational attainment and AL status with long-term risk of cancer mortality, and whether education moderated the association between AL and cancer mortality.

METHODS

We performed a retrospective analysis among 4,677 AA women within the National Health and Nutrition Examination Survey (NHANES) from 1988 to 2010 with follow-up data through December 31, 2019. We fit weighted Cox proportional hazards models to estimate adjusted hazard ratios (aHRs) of cancer death between educational attainment/AL (adjusted for age, income, and smoking status).

RESULTS

AA women with less than a high school diploma living with high AL had nearly a 3-fold increased risk (unadjusted HR: 2.98; 95%C CI: 1.24-7.15) of cancer death compared to AA college graduates living with low AL. However, after adjusting for age, this effect attenuated (age-adjusted HR: 1.11; 95% CI: 0.45-2.74). AA women with high AL had 2.3-fold increased risk of cancer death (fully adjusted HR: 2.26; 95% CI: 1.10-4.57) when compared to AA with low AL, specifically among women with high school diploma or equivalent and without history of cancer.

CONCLUSIONS

Our findings suggest that high allostatic load is associated with a higher risk of cancer mortality among AA women with lower educational attainment, while no such association was observed among AA women with higher educational attainment. Thus, educational attainment plays a modifying role in the relationship between allostatic load and the risk of cancer death for AA women. Higher education can bring several benefits, including improved access to medical care and enhanced medical literacy, which in turn may help mitigate the adverse impact of AL and the heightened risk of cancer mortality among AA women.

Clarity on Disparity: Who, What, When, Where, Why, and How

This article offers a framework of who, what, when, where, why, and how of health disparities that can serve as a systematic approach to move from description to understanding causes and taking action to ensure health equity.

Allostatic load and incident heart failure in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study

BACKGROUND

Allostatic load (AL) is the physiologic "wear and tear" on the body from stress. Yet, despite stress being implicated in the development heart failure (HF), it is unknown whether AL is associated with incident HF events.

METHODS

We examined 16,765 participants without HF at baseline from the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. The main exposure was AL score quartile. AL was determined according to 11 physiologic parameters, whereby each parameter was assigned points (0-3) based on quartiles within the sample, and points were summed to create a total AL score ranging from 0-33. The outcome was incident HF event. We examined the association between AL quartile (Q1-Q4) and incident HF events using Cox proportional hazards models, adjusted for demographics, socioeconomic factors, and lifestyle.

RESULTS

The mean age was 64 ± 9.6 years, 61.5% were women, and 38.7% were Black participants. Over a median follow up of 11.4 years, we observed 750 incident HF events (635 HF hospitalizations and 115 HF deaths). Compared to the lowest AL quartile (Q1), the fully adjusted hazards of an incident HF event increased in a graded fashion: Q2 HR 1.49 95% CI 1.12-1.98; Q3 HR 2.47 95% CI 1.89-3.23; Q4 HR 4.28 95% CI 3.28-5.59. The HRs for incident HF event in the fully adjusted model that also adjusted for CAD were attenuated, but remained significant and increased in a similar, graded fashion by AL quartile. There was a significant age interaction (p-for-interaction < 0.001), whereby the associations were observed across each age stratum, but the HRs were highest among those aged < 65 years.

CONCLUSION

AL was associated with incident HF events, suggesting that AL could be an important risk factor and potential target for future interventions to prevent HF.

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.

Towards a consensus definition of allostatic load: a multi-cohort, multi-system, multi-biomarker individual participant data (IPD) meta-analysis

BACKGROUND

Allostatic load (AL) is a multi-system composite index for quantifying physiological dysregulation caused by life course stressors. For over 30 years, an extensive body of research has drawn on the AL framework but has been hampered by the lack of a consistent definition.

METHODS

This study analyses data for 67,126 individuals aged 40-111 years participating in 13 different cohort studies and 40 biomarkers across 12 physiological systems: hypothalamic-pituitary-adrenal (HPA) axis, sympathetic-adrenal-medullary (SAM) axis, parasympathetic nervous system functioning, oxidative stress, immunological/inflammatory, cardiovascular, respiratory, lipidemia, anthropometric, glucose metabolism, kidney, and liver. We use individual-participant-data meta-analysis and exploit natural heterogeneity in the number and type of biomarkers that have been used across studies, but a common set of health outcomes (grip strength, walking speed, and self-rated health), to determine the optimal configuration of parameters to define the concept.

RESULTS

There was at least one biomarker within 9/12 physiological systems that was reliably and consistently associated in the hypothesised direction with the three health outcomes in the meta-analysis of these cohorts: dehydroepiandrosterone sulfate (DHEAS), low frequency-heart rate variability (LF-HRV), C-reactive protein (CRP), resting heart rate (RHR), peak expiratory flow (PEF), high density lipoprotein cholesterol (HDL-C), waist-to-height ratio (WtHR), HbA1c, and cystatin C. An index based on five biomarkers (CRP, RHR, HDL-C, WtHR and HbA1c) available in every study was found to predict an independent outcome - mortality - as well or better than more elaborate sets of biomarkers.

DISCUSSION

This study has identified a brief 5-item measure of AL that arguably represents a universal and efficient set of biomarkers for capturing physiological 'wear and tear' and a further biomarker (PEF) that could usefully be included in future data collection.

Cumulative physiological stress is associated with age-related changes to peripheral T lymphocyte subsets in healthy humans

BACKGROUND

Progressive age-associated change in frequencies and functional capacities of immune cells is known as immunosenescence. Despite data linking chronic environmental, physiological, and psychosocial stressors with accelerated aging, how stress contributes to immunosenesence is not well characterized.

OBJECTIVE

To help delineate the contribution of cumulative physiological stress on immunosensence we assessed relationships between a composite measurement of cumulative physiological stress, reflecting the functioning of the hypothalamic-pituitary-adrenal axis, sympathetic nervous system, cardiovascular system, and metabolic processes, and lymphocyte changes typically affiliated with aging in a cohort of healthy volunteers ranging from 18 to 66 y.

RESULTS

Physiological stress load positively correlated with subject age in the study cohort and was significantly higher in adults 50-66 y compared to adults 18-33 y and 34-49 y. Using physiological stress load, we identified a significant age-dependent association between stress load and frequencies of circulating regulatory T lymphocytes (Tregs). Frequencies were higher in younger participants, but only in participants exhibiting low physiological stress load. As stress load increased, frequencies of Tregs decreased in young participants but were unchanged with increasing stress load in middle and older age individuals. Follow-up analysis of stress load components indicated lower circulating DHEA-S and higher urinary norepinephrine as the primary contributors to the effects of total stress load on Tregs. In addition, we identified age-independent inverse associations between stress load and frequencies of naïve Tregs and naïve CD4 T cells and positive associations between stress load and frequencies of memory Tregs and memory CD4 T cells. These associations were primarily driven by stress load components waist circumference, systolic and diastolic blood pressure, CRP, and HbA1c. In summary, our study results suggest that, in younger people, physiological stress load may diminish regulatory T cell frequencies to levels seen in older persons. Furthermore, independent of age, stress load may contribute to contraction of the naïve Treg pool and accumulation of memory Treg cells.

CLINICAL TRIAL

Registered on ClincialTrials.gov (Identifier: NCT02367287).

Association between allostatic load and adverse outcomes among older patients with heart failure with preserved ejection fraction

BACKGROUND

The allostatic load (AL) refers to the cumulative weakening of multiple physiological systems caused by repeated adaptation of the body to stressors There are still no studies have focused on the association between AL and the prognosis of patients with heart failure with preserved ejection fraction (HFpEF). The present study aimed to investigate the association between AL and adverse outcomes, including mortality and HF admission, among elderly male patients with HFpEF.

METHODS

We conducted a prospective cohort study of 1111 elderly male patients with HFpEF, diagnosed between 2015 and 2019 and followed up through 2021. We constructed an AL measure using a combination of 12 biomarkers. The diagnosis of HFpEF was made according to the 2021 European Society of Cardiology guidelines. A Cox proportional hazards model was used to determine the associations between AL and adverse outcomes.

RESULTS

In multivariate analysis, AL was significantly associated with increased risk of all-cause mortality (medium AL: adjusted hazard ratio [HR] = 2.53; 95% confidence interval [CI] 1.37-4.68; high AL: HR = 4.21; 95% CI 2.27-7.83; per-score increase: HR = 1.31; 95% CI 1.18-1.46), cardiovascular mortality (medium AL: HR = 2.67; 95% CI 1.07-6.68; high AL: HR = 3.13; 95% CI 1.23-7.97; per-score increase: HR = 1.20; 95% CI 1.03-1.40), non-cardiovascular mortality (medium AL: HR = 2.45; 95% CI 1.06-5.63; high AL: HR = 5.81; 95% CI 2.55-10.28; per-score increase: HR = 1.46; 95% CI 1.26-1.69), and HF admission (medium AL: HR = 2.68; 95% CI 1.43-5.01; high AL: HR = 3.24; 95% CI 1.69-6.23; per-score increase: HR = 1.24; 95% CI 1.11-1.39). Consistent results were found in multiple subgroup analyses.

CONCLUSIONS

A higher AL was associated with poor prognosis in elderly men with HFpEF. AL relies on information that is easily obtained in physical examinations and laboratory parameters and can be assessed in various care and clinical settings to help risk stratification of HFpEF patients.

The roles of non-heterosexuality outside of identity and gender non-conformity in Allostatic Load among young adults

Using the National Longitudinal Study of Adolescent to Adult Health, this study contrasted levels of Allostatic Load at the baseline and change observed between the age 20s and 30s, among self-identified Lesbians/Gays/Bisexuals and heterosexuals with non-heterosexual attraction/behavior (discordant heterosexuals), against heterosexuals without (concordant heterosexuals). In addition, the study tested if Allostatic Load differs for each of the sexual orientation group differs jointly or independently of gender non-conformity. The study found no Allostatic Load elevation for self-identified non-heterosexual men and women. For women only, a significantly greater elevation of Allostatic Load is observed among discordant heterosexuals. Independently, Allostatic Load is found higher for females appearing more androgynous. The findings suggest expanding the current scope of sexual minority research to consider the relevance of minority stress to those without a LGB identity, who may be exposed to stress from disparate sources related to their gender identity.

Allostatic Load and Endocrine Disorders

The building of life stress, well expressed by the concept of allostatic load, plays an important part in all phases of endocrine illness. Allostatic load refers to the cumulative burden of both stressful life events and chronic stress. When environmental challenges exceed the individual ability to cope, allostatic overload ensues. Assessment of allostatic load/overload by clinical measurements including indices and rating scales, in addition to biomarkers, offers a characterization of the person's psychosocial environment that is missing from current formulations. Consideration of allostatic load in endocrinology may shed light on a number of clinical issues: interpretation of abnormal hormone values that lack explanations; coping with the various phases of illness; maladaptive illness behavior; response to treatment; presence of residual symptoms; health-damaging lifestyle habits. Addressing allostatic load calls for innovative models of endocrine outpatients with multidisciplinary organization of care, extended time for the interview, focus on rehabilitation. We provide an overview on the mechanisms of allostatic load, how it can be assessed, its potential role in endocrine disturbances, and how its consideration may lead to a needed innovation in patient care.

Resilience to Maltreatment in Early Adulthood Does Not Predict Low Allostatic Load at Midlife

BACKGROUND

Although childhood maltreatment is associated with a host of poor health and social outcomes in adulthood, many individuals manifest resilience.

PURPOSE

We tested competing predictions about whether achieving positive psychosocial outcomes in young adulthood would be differentially predictive of allostatic load at midlife for those with and without a childhood history of maltreatment.

METHODS

The sample included 808 individuals, 57% of whom had court-documented records of childhood abuse or neglect between 1967 and 1971, and demographically matched controls without those histories. Participants provided information on socioeconomic, mental health, and behavioral outcomes in interviews conducted between 1989 and 1995 (mean age = 29.2 years). Indicators of allostatic load were measured between 2003 and 2005 (mean age = 41.2 years).

RESULTS

The relationship between positive life outcomes in young adulthood and allostatic load in middle adulthood varied depending on childhood maltreatment status (b = .16, 95% CI: .03; .28); for adults who did not experience childhood maltreatment, more positive life outcomes predicted lower allostatic load (b = -.12, 95% CI: -.23; -.01), whereas the relationship was not significant for adults with a childhood history of maltreatment (b = .04, 95% CI: -.06; .13). There were no differences in the results predicting allostatic load for African-American and White respondents.

CONCLUSIONS

Childhood maltreatment may have enduring effects on physiological functioning that are manifest in elevated allostatic load scores in middle age. Alternatively, resilience to maltreatment-as manifest in positive functioning in socioeconomic and behavioral domains-may not be sufficiently stable over adulthood to buffer individuals from the physiological consequences of stressful environments.

Resilience by design: How nature, nurture, environment, and microbiome mitigate stress and allostatic load

Resilience to psychological stress is defined as adaption to challenging life experiences and not the absence of adverse life events. Determinants of resilience include personality traits, genetic/epigenetic modifications of genes involved in the stress response, cognitive and behavioral flexibility, secure attachment with a caregiver, social and community support systems, nutrition and exercise, and alignment of circadian rhythm to the natural light/dark cycle. Therefore, resilience is a dynamic and flexible process that continually evolves by the intersection of different domains in human’s life; biological, social, and psychological. The objective of this minireview is to summarize the existing knowledge about the multitude factors and molecular alterations that result from resilience to stress response. Given the multiple contributing factors in building resilience, we set out a goal to identify which factors were most supportive of a causal role by the current literature. We focused on resilience-related molecular alterations resulting from mind-body homeostasis in connection with psychosocial and environmental factors. We conclude that there is no one causal factor that differentiates a resilient person from a vulnerable one. Instead, building resilience requires an intricate network of positive experiences and a healthy lifestyle that contribute to a balanced mind-body connection. Therefore, a holistic approach must be adopted in future research on stress response to address the multiple elements that promote resilience and prevent illnesses and psychopathology related to stress allostatic load.

Physical activity is associated with allostatic load: Evidence from the National Health and Nutrition Examination Survey

We determined the associations between physical activity and allostatic load, and whether it is a modifiable factor related to allostatic load. We obtained data from the National Health and Nutrition Examination Survey (NHANES) database collected between 2017 and March 2020. The relationship between physical activity and allostatic load was examined using a logistic regression model. In the unadjusted model, physical activity level was associated with allostatic load index (odds ratio [OR] = 0.664, 95% confidence interval [CI]: 0.550, 0.802, P＜0.001), with this relationship being retained in the adjusted model (OR = 0.739, 95%CI: 0.603, 0.907; P = 0.004). Sedentary behaviour was also related to allostatic load index (OR = 1.236, 95%CI: 1.005, 1.520; P = 0.044). Our findings indicated that sufficient physical activity is associated with a lower allostatic load index, and sedentary behaviour is associated with a higher allostatic load index. Physical activity is a modifiable factor related to allostatic load.

Trajectories in allostatic load as predictors of sleep quality among urban adults: Healthy aging in neighborhoods of diversity across the life span study

OBJECTIVE

/Background: The allostatic framework is a theoretical perspective that identifies allostatic load (AL) as a meaningful measure of dysregulation and desynchrony across biological processes due to cumulative stress exposure, thereby increasing disease risk. Research exploring the relationships of AL with sleep quality have yielded inconsistent findings. We examined AL at three visits (2004-2009 [Visit 1], 2009-2013 [Visit 2] and 2013-2017 [Visit 3]) in relation to sleep quality [Visit 3] among urban adults by sex, race and age group.

PATIENTS/METHODS

We analyzed data on 1489 Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) participants [59.6% female, baseline age: 48.2 years, 58.5% African Americans] with available data on cardiovascular, metabolic and inflammatory AL markers and Pittsburgh Sleep Quality Index (PSQI) scores. Least squares regression models were constructed to evaluate AL score at Visit 1 (AL_v1) and z-transformed probability of higher trajectory in AL score between Visit 1 and Visit 3 (AL_traj) as predictors of PSQI score at Visit 3, controlling for demographic, lifestyle and health characteristics at Visit 1. AL_traj was generated using group-based trajectory modeling.

RESULTS

In fully adjusted models, AL_v1 and PSQI score were positively related among men only (β = 0.43, P = 0.001), whereas higher AL_traj was associated with PSQI score among women (β = 0.51, P = 0.001), White (β = 0.45, P = 0.011) and African American (β = 0.33, P = 0.014) populations. There were no statistically significant interactions according to age group (<50 vs. ≥ 50).

CONCLUSIONS

Disparities exist whereby AL trajectory predicted sleep quality among women irrespective of race and baseline AL predicted sleep quality among men. Future studies should examine bi-directional AL-sleep relationships.