Predicting mortality from clinical and nonclinical biomarkers

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.

Late-life depression, allostatic load, and risk of dementia: The AGES-Reykjavik study

BACKGROUND

The current study aimed to assess if the relation between depression and dementia could be explained by allostatic load (AL) profiles, as well as assessing their risk on incident all-cause dementia, Alzheimer's disease (AD), and non-AD dementias.

METHODS

The study included individuals without dementia at baseline from the population-based AGES-Reykjavik Study. Depressive symptoms assessed with the Geriatric Depression Scale-15 and AL markers were collected at baseline. Latent profile analysis (LPA) was performed on the AL markers. Incident dementia was measured during 12-years of follow-up. Cox regressions adjusted for AL profiles were performed to evaluate if AL could explain the relation between depressive symptoms and incident dementia. Additional Cox regressions exploring the interaction with depressive symptoms and AL profiles were also performed.

RESULTS

LPA revealed four profiles based on AL factors: 'Low cardiovascular dysregulation' (43 %), 'Average' (42 % prevalence), 'High cardiovascular dysregulation' (11 %), and 'Multisystem dysregulation' (4 %). Cox regression analyses found an increased risk for dementia in the 'Multisystem dysregulation' group (HR 1.72; 95 % CI 1.26-2.33), as well as for AD (HR 1.75; 95 % CI: 1.12-2.71) and non-AD dementias (HR 1.87; 95 % CI: 1.23-2.84). AL profiles did not mediate the risk of all-cause dementia with depressive symptoms; however, there was evidence of additive interaction with depressive symptoms and the 'Multisystem dysregulation' profile and all-cause dementia (RERI 0.15; 95 % CI 0.03-0.26).

CONCLUSION

AL profiles and depressive symptoms were independently related to dementia. Individuals with multisystem dysregulation could be more susceptible to the negative effects of depressive symptomology on incident dementia.

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.

End-of-Life Planning Depends on Socio-Economic and Racial Background: Evidence from the US Health and Retirement Study (HRS)

CONTEXT

Americans express a strong preference for participating in decisions regarding their medical care, yet they are often unable to participate in decision-making regarding their end-of-life care.

OBJECTIVE

To examine determinants of end-of-life planning; including, the effect of an individual's ageing and dying process, health status and socio-economic and racial/ethnic background.

METHODS

US observational cohort study, using data from the Health and Retirement Study (1992 - 2014) including 37,494 individuals. Random-effects logistic regression analysis was used to examine the relationship between the presence of a living will and a range of individual time-varying characteristics, including time to death, and several time-invariant characteristics.

RESULTS

End-of-life planning depends on several patient characteristics and circumstances, with socio-economic and racial/ethnic background having the largest effects. The probability of having a living will rises sharply late in life, as we would expect, and is further modified by the patient's proximity to death. The dying process, exerts a stronger influence on end-of-life planning than does the aging.

CONCLUSIONS

Understanding differences that increase end-of-life planning is important to incentivize patients' participation. Advance planning should be encouraged and accessible to people of all ages as it is inevitable for the provision of patient-centered and cost-effective care.

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

BACKGROUND

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

Using biomarkers to predict healthcare costs: Evidence from a UK household panel

We investigate the extent to which healthcare service utilisation and costs can be predicted from biomarkers, using the UK Understanding Society panel. We use a sample of 2314 adults who reported no history of diagnosed long-lasting health conditions at baseline (2010/11), when biomarkers were collected. Five years later, their GP, outpatient (OP) and inpatient (IP) utilisation was observed. We develop an econometric technique for count data observed within ranges and a method of combining administrative reference cost data with the survey data without exact individual-level matching. Our composite biomarker index (allostatic load) is a powerful predictor of costs: for those with a baseline allostatic load of at least one standard deviation (1-s.d.) above mean, a 1-s.d. reduction reduces GP, OP and IP costs by around 18%.

Sex × Gender and Sexual Orientation in Relation to Stress Hormones and Allostatic Load

In this selective review, emerging literature linking biological sex, sociocultural gender, and sexual orientation to stress hormone functioning and multisystemic physiological dysregulations are summarized. Beyond sex as a binary biological variable, continuums of sex hormones, gender roles, gender identity, and sexual orientation each uniquely help delineate pathways and mechanisms linked to stress-related disease trajectories. This implicates glucocorticoid functioning and allostatic load, the “wear and tear” of chronic stress in synergy with unhealthy behaviors. Clinical considerations are also discussed for the field of gender medicine.

How stress mediators can cumulatively contribute to Alzheimer's disease An allostatic load approach

Allostatic load is defined as the frequent activation of the neuroendocrine, immunological, metabolic and cardiovascular systems, which makes individuals more susceptible to stress-related health problems. According to this model, physiological dysregulations start to emerge decades before diseases manifest. Consequently, stress research has shifted its attention to anticipating the degree of this dysregulation to better understand the impact of stress hormones and other biomarkers on disease progression. In view of the growing number of studies that demonstrate the influence of modifiable risk factors on cognitive decline, in addition to the effects of chronic stress mediators, the objective of the present review was to present an overview of the development of cognitive changes based on studies on stress and its mediators.

Adult Children's Education and Physiological Dysregulation Among Older Parents

Objectives

Despite growing awareness that children's education benefits the health of older parents, the underlying mechanisms of this relationship are not well-understood. We investigated (a) the associations between children's education and biological functioning of parents, (b) psychosocial and behavioral factors that explain the associations, and (c) gendered patterns in the associations.

Methods

Using longitudinal data from a nationally representative sample of older Taiwanese, we performed mediation analysis of the association between adult children's education and physiological dysregulation of their parents.

Results

Offspring's schooling is inversely associated with parental inflammation after controlling for parental socioeconomic status and baseline health. Parents who have well-educated children report higher social standing and life satisfaction, experience fewer stressful events, and are more likely to engage in healthy behaviors related to smoking and diet. These factors moderately attenuate the associations between children's education and parental inflammation. There is no conclusive evidence that mothers and fathers benefit differently from having well-educated children.

Discussion

Parents who devote family and personal resources to their offspring's schooling may have better biological profiles in later life. Well-educated children may promote their parents' wellbeing by strengthening perceived social status, reducing exposure to stressors, and encouraging a healthy lifestyle.

Neighborhood Socioeconomic Deprivation and Allostatic Load: A Scoping Review

Residing in socioeconomically deprived neighborhoods may pose substantial physiological stress, which can then lead to higher allostatic load (AL), a marker of biological wear and tear that precedes disease. The aim of the present study was to map the current evidence about the relationship between neighborhood socioeconomic deprivation and AL. A scoping review approach was chosen to provide an overview of the type, quantity, and extent of research available. The review was conducted using three bibliographic databases (PubMed, SCOPUS, and Web of Science) and a standardized protocol. Fourteen studies were identified. Studies were predominantly from the USA, cross-sectional, focused on adults, and involved different races and ethnic groups. A wide range of measures of AL were identified: the mode of the number of biomarkers per study was eight but with large variability (range: 6⁻24). Most studies (n = 12) reported a significant association between neighborhood deprivation and AL. Behaviors and environmental stressors seem to mediate this relationship and associations appear more pronounced among Blacks, men, and individuals with poor social support. Such conclusions have important public health implications as they enforce the idea that neighborhood environment should be improved to prevent physiological dysregulation and consequent chronic diseases.

Predicting Receipt of Social Security Administration Disability Benefits Using Biomarkers and Other Physiological Measures: Evidence From the Health and Retirement Study

OBJECTIVES

The objective of this study was to assess how well physiological measures, including biomarkers and genetic indicators, predict receipt of Social Security Administration (SSA) disability benefits among U.S. adults aged 51 to 65 years.

METHOD

We used data from the 2006 to 2012 waves of the Health and Retirement Study (HRS), linked to SSA administrative data. Using logistic regression, we predicted benefit receipt (either Social Security Disability Insurance or Supplemental Security Income) using 19 distinct physiological markers, adjusting for age, sex, race, and select medication use. We then calculated the propensity (i.e., predicted probability) that each HRS respondent received benefits and assessed how well propensity score-based classifications could identify beneficiaries and nonbeneficiaries.

RESULTS

Thirteen percent of respondents received benefits. Using the propensity score cut point that maximized the sum of sensitivity and specificity, the model correctly predicted 75.9% of beneficiaries and 73.5% of nonbeneficiaries.

DISCUSSION

Physiological measures have moderate power to predict SSA disability benefit receipt.

Physiological Dysregulation, Frailty, and Risk of Mortality Among Older Adults

This study examines whether frailty is associated with mortality independently of physiological dysregulation (PD) and, if so, which is the more accurate predictor of survival. Data come from the Social Environment and Biomarkers of Aging Study. We use Cox proportional hazard models to test the associations between PD, frailty, and 4- to 5-year survival. We use Harrell's concordance index to compare predictive accuracy of the models. Both PD and frailty are significantly, positively, and independently correlated with mortality: Worse PD scores and being frail are associated with a higher risk of dying. The overall PD score is a more accurate predictor of survival than frailty, although model prediction improves when both measures are included. PD and frailty independently predict mortality, suggesting that the two measures may be capturing different aspects of the same construct and that both may be important for identifying individuals at risk for adverse health outcomes.

A Conceptual Model to Assess Stress-Associated Health Effects of Multiple Ecosystem Services Degraded by Disaster Events in the Gulf of Mexico and Elsewhere

Few conceptual frameworks attempt to connect disaster-associated environmental injuries to impacts on ecosystem services (the benefits humans derive from nature) and thence to both psychological and physiological human health effects. To our knowledge, this study is one of the first, if not the first, to develop a detailed conceptual model of how degraded ecosystem services affect cumulative stress impacts on the health of individual humans and communities. Our comprehensive Disaster-Pressure State-Ecosystem Services-Response-Health (DPSERH) model demonstrates that oil spills, hurricanes, and other disasters can change key ecosystem components resulting in reductions in individual and multiple ecosystem services that support people's livelihoods, health, and way of life. Further, the model elucidates how damage to ecosystem services produces acute, chronic, and cumulative stress in humans which increases risk of adverse psychological and physiological health outcomes. While developed and initially applied within the context of the Gulf of Mexico, it should work equally well in other geographies and for many disasters that cause impairment of ecosystem services. Use of this new tool will improve planning for responses to future disasters and help society more fully account for the costs and benefits of potential management responses. The model also can be used to help direct investments in improving response capabilities of the public health community, biomedical researchers, and environmental scientists. Finally, the model illustrates why the broad range of potential human health effects of disasters should receive equal attention to that accorded environmental damages in assessing restoration and recovery costs and time frames.

The streamlined Allostatic Load Index: a replication of study results

According to the World Health Organization stress in the workplace is becoming a major challenge of employers worldwide. While perceived stress levels can be assessed by questionnaires there is growing evidence that stress-related wear and tear of our body can be measured by the Allostatic Load Index (ALI). In a sample of 12,477 German industrial employees (19.6% female, 18-65 years) self-rated stress was explored by the effort-reward imbalance (ERI) questionnaire. A voluntary health check included biomarkers such as diastolic blood pressure, waist circumference, glycosylated hemoglobin, low-density lipoprotein, and heart rate variability. Based on predefined subclinical cutoff values, a 5-variable ALI was calculated. Differences in ALI according to low (ERI ≤1.0) and high (ERI >1.0) stress levels were tested. The association of ERI and ALI was explored using logistic regression analysis controlling for multiple confounders. Employees perceiving high stress levels showed significant higher ALI scores (p < .001) compared to lower stressed employees. This association was stronger in men and independent of age. ALI was associated with work stress in adjusted models (OR 1.18 ± .08 [95% CI 1.03, 1.36]; p < .05). This study replicates former results in a large sample of industrial employees indicating that work stress is associated with a short form ALI.

Allostatic Load Assessment for Early Detection of Stress in the Workplace in Egypt

AIM:

Workplace stress is hazardous for its harmful impact on employees’ health and organizational productivity. The aim of the study is to apply the Allostatic Load Index (ALI) which is a multi-component measure for health risk assessment and early detection of stress among workers in Egypt.

METHODS:

Sixty-two working adults randomly selected from two different working environments in Egypt were included in the study. Participants completed a self-reported questionnaire for socio-demographic and work variables. Andrews and Withey test for Job Satisfaction was filled and 3 ml blood samples were collected. Markers assessed for Allostatic Load were serum cortisol, c-reactive protein, dehydroepiandrosterone-sulphate, total thyroxine, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, total cholesterol to high-density lipoprotein ratio, systolic and diastolic blood pressures, waist to hip ratio and body mass index. The risk quartile method was used for calculation of ALI. ALI value of four or more indicates high Allostatic Load.

RESULTS:

Job satisfaction scale defined about a quarter of the study population (24%) to be dissatisfied with Allostatic Load of 2.4 as the mean value. Population percentage with ALI ≥4 reached 12.9% with 100% of them females. A significant association was found between Allostatic Load of primary mediators and age, the presence of chronic diseases, place of work and female gender.

CONCLUSION:

Female gender and the old age of the Egyptian workforce under study are at higher risk of chronic diseases. Using an alternative way -for example, the cut-point method- instead of the risk quartiles for dichotomization of markers used in ALI calculation could be more precise for early detection of stress among healthy individuals.

Past, Present, and Future of Healthy Life Expectancy

The success of the current biomedical paradigm based on a "disease model" may be limited in the future because of large number of comorbidities inflicting older people. In recent years, there has been growing empirical evidence, based on animal models, suggesting that the aging process could be delayed and that this process may lead to increases in life expectancy accompanied by improvements in health at older ages. In this review, we explore past, present, and future prospects of healthy life expectancy and examine whether increases in average length of life associated with delayed aging link with additional years lived disability-free at older ages. Trends in healthy life expectancy suggest improvements among older people in the United States, although younger cohorts appear to be reaching old age with increasing levels of frailty and disability. Trends in health risk factors, such as obesity and smoking, show worrisome signs of negative impacts on adult health and mortality in the near future. However, results based on a simulation model of delayed aging in humans indicate that it has the potential to increase not only the length of life but also the fraction and number of years spent disability-free at older ages. Delayed aging would likely come with additional aggregate costs. These costs could be offset if delayed aging is widely applied and people are willing to convert their greater healthiness into more years of work.

Target values of cardiovascular risk factors are not associated with all-cause mortality in patients with type 2 diabetes mellitus

BACKGROUND

To investigate prospectively the relationship between target values of glycated hemoglobin, blood pressure and LDL-cholesterol, as considered in a combined fashion, and all-cause mortality in patients with type 2 diabetes mellitus.

METHODS

Two cohorts of patients with type 2 diabetes mellitus, the Gargano Mortality Study (n=810) and the Foggia Mortality Study (n=929), were investigated. A weighted target risk score was built as a weight linear combination of the recommended targets reached by each patient.

RESULTS

In the Gargano Mortality Study and in the Foggia Mortality Study (mean follow up=7.4 and 5.5 years, respectively), 161 (19.9%) and 220 (23.7%) patients died, with an age and sex adjusted annual incidence rate of 2.1 and 2.8 per 100 person-years, respectively. In both study samples the weighted target risk score tended to be linearly associated with all-cause mortality (HR for one point increment=1.30, 95% CI: 1.11-1.53, p=0.001, and HR=1.08, 95% CI: 0.95-1.24, p=0.243, respectively). When the two cohorts were pooled and analyzed together, a clear association between weighted target risk score and all-cause mortality was observed (HR for one point increment=1.17, 95% CI:1.05-1.30, p=0.004). This counterintuitive association was no longer observable in a model including age, sex, body mass index, smoking habit, estimated glomerular filtration rate, albuminuria and anti-diabetic, anti-hypertensive and anti-dyslipidemic treatment as covariates (HR for one point increment=0.99, 95% CI: 0.87-1.12, p=0.852).

CONCLUSIONS

In a real life clinical set of patients with type 2 diabetes mellitus, the combination of recommended target values of established cardiovascular risk factors is not associated with all-cause mortality.

Disability Trajectories at the End of Life: A "Countdown" Model

OBJECTIVES

Studies of late-life disablement typically address the role of advancing age as a factor in developing disability, and in some cases have pointed out the importance of time to death (TTD) in understanding changes in functioning. However, few studies have addressed both factors simultaneously, and none have dealt satisfactorily with the problem of missing data on TTD in panel studies.

METHODS

We fit latent-class trajectory models of disablement using data from the Health and Retirement Study. Among survivors (~20% of the sample), TTD is unknown, producing a missing-data problem. We use an auxiliary regression equation to impute TTD and employ multiple imputation techniques to obtain final parameter estimates and standard errors.

RESULTS

Our best-fitting model has 3 latent classes. In all 3 classes, the probability of having a disability increases with nearness to death; however, in only 2 of the 3 classes is age associated with disability. We find gender, race, and educational differences in class-membership probabilities.

DISCUSSION

The model reveals a complex pattern of age- and time-dependent heterogeneity in late-life disablement. The techniques developed here could be applied to other phenomena known to depend on TTD, such as cognitive change, weight loss, and health care spending.

Association of allostatic load with brain structure and cognitive ability in later life

Allostatic load (AL) has been proposed as a general framework for understanding the cumulative effects of life stress on individuals. Despite growing interest in AL, limited research has been conducted on aging samples. We consider the association of AL (operationalized by a range of inflammatory, cardiovascular, and metabolic measures) with a range of brain volume measurements and cognitive ability in a large cohort sample of older adults (n = 658, mean age = 72.5 years, standard deviation = 0.7) using structural equation modeling. AL was significantly inversely associated with total brain volume (range of standardized β = -0.16 to -0.20) and white-matter volume (-0.35 to -0.36) and positively with hippocampal volume (0.10-0.15) but not gray-matter volume (0.04). AL was also significantly inversely associated with general cognitive ability (range β = -0.13 to -0.20), processing speed (-0.20 to -0.22), and knowledge (-0.18 to -0.20) but not memory or nonverbal reasoning. The associations of AL with cognitive abilities were not mediated by these brain volume measures. AL did not predict cognitive change from age 11 to approximately age 73. The findings suggest a link between AL and later life brain health and cognitive functioning.

Measuring allostatic load in the workforce: a systematic review

The Allostatic Load Index (ALI) has been used to establish associations between stress and health-related outcomes. This review summarizes the measurement and methodological challenges of allostatic load in occupational settings. Databases of Medline, PubPsych, and Cochrane were searched to systematically explore studies measuring ALI in working adults following the PRISMA statement. Study characteristics, biomarkers and methods were tabulated. Methodological quality was evaluated using a standardized checklist. Sixteen articles (2003-2013) met the inclusion criteria, with a total of 39 (range 6-17) different variables used to calculate ALI. Substantial heterogeneity was observed in the number and type of biomarkers used, the analytic techniques applied and study quality. Particularly, primary mediators were not regularly included in ALI calculation. Consensus on methods to measure ALI in working populations is limited. Research should include longitudinal studies using multi-systemic variables to measure employees at risk for biological wear and tear.

A streamlined approach for assessing the Allostatic Load Index in industrial employees

Work stress is common and can lead to various bodily dysfunctions. The Allostatic Load Index (ALI) is a tool to measure the wear and tear of the body caused by chronic stress. This cross-sectional study aimed to explore the association of work-related stress and ALI in German industrial employees. A short form ALI should be developed for practical use of company physicians. In this exploration of an industrial cohort (n = 3797; 79.3% male), work stress was measured by the effort-reward imbalance (ERI) questionnaire in 2009-2011. ALI was calculated using 15 variables including anthropometric data, heart rate variability, as well as blood and urine samples based on predefined subclinical cut-off values. Differences in ALI related to low (≤1) and high (>1) ERI categories were tested. Logistic regression models estimated odds ratios (ORs) and corresponding 95% confidence intervals (CIs) for the association between ALI and work stress controlling for multiple confounders. Employees exposed to high work stress showed higher ALI scores (p < 0.001) compared to those with low stress levels. In multivariable models, ALI was associated with work stress (OR 1.19 [95% CI: 1.00, 1.42]; p < 0.05) following adjustment for a range of potential confounders. By reducing ALI parameters to five variables this association increased modestly and remained statistically significant (OR 1.27 [95% CI: 1.05, 1.54]; p < 0.05). The results indicate that work stress is associated with ALI in German industrial employees. A short form index seems to be a promising approach for occupational health practitioners. The results should be validated in further longitudinal explorations defining a standard set of variables including gender-related thresholds.

Olfactory dysfunction predicts 5-year mortality in older adults

Prediction of mortality has focused on disease and frailty, although antecedent biomarkers may herald broad physiological decline. Olfaction, an ancestral chemical system, is a strong candidate biomarker because it is linked to diverse physiological processes. We sought to determine if olfactory dysfunction is a harbinger of 5-year mortality in the National Social Life, Health and Aging Project [NSHAP], a nationally representative sample of older U.S. adults. 3,005 community-dwelling adults aged 57–85 were studied in 2005–6 (Wave 1) and their mortality determined in 2010–11 (Wave 2). Olfactory dysfunction, determined objectively at Wave 1, was used to estimate the odds of 5-year, all cause mortality via logistic regression, controlling for demographics and health factors. Mortality for anosmic older adults was four times that of normosmic individuals while hyposmic individuals had intermediate mortality (p<0.001), a “dose-dependent” effect present across the age range. In a comprehensive model that included potential confounding factors, anosmic older adults had over three times the odds of death compared to normosmic individuals (OR, 3.37 [95%CI 2.04, 5.57]), higher than and independent of known leading causes of death, and did not result from the following mechanisms: nutrition, cognitive function, mental health, smoking and alcohol abuse or frailty. Olfactory function is thus one of the strongest predictors of 5-year mortality and may serve as a bellwether for slowed cellular regeneration or as a marker of cumulative toxic environmental exposures. This finding provides clues for pinpointing an underlying mechanism related to a fundamental component of the aging process.

Cohort Profile: The Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan

The Social Environment and Biomarkers of Aging Study (SEBAS) is a nationally representative longitudinal survey of Taiwanese middle-aged and older adults. It adds the collection of biomarkers and performance assessments to the Taiwan Longitudinal Study of Aging (TLSA), a nationally representative study of adults aged 60 and over, including the institutionalized population. The TLSA began in 1989, with follow-ups approximately every 3 years; younger refresher cohorts were added in 1996 and 2003. The first wave of SEBAS, based on a sub-sample of respondents from the 1999 TLSA, was conducted in 2000. A total of 1023 respondents completed both a face-to-face home interview and, several weeks later, a hospital-based physical examination. In addition to a 12-h (7 pm-7 am) urine specimen collected the night before and a fasting blood specimen collected during the examination, trained staff measured blood pressure, height, weight and waist and hip circumferences. A second wave of SEBAS was conducted in 2006 using a similar protocol to SEBAS 2000, but with the addition of performance assessments conducted by the interviewers at the end of the home interview. Both waves of SEBAS also included measures of health status (physical, emotional, cognitive), health behaviours, social relationships and exposure to stressors. The SEBAS data, which are publicly available at [http://www.icpsr.umich.edu/icpsrweb/NACDA/studies/3792/version/5], allow researchers to explore the relationships among life challenges, the social environment and health and to examine the antecedents, correlates and consequences of change in biological measures and health.

Beyond Self-Reports: Changes in Biomarkers as Predictors of Mortality

The proliferation of biosocial surveys has increased the importance of weighing the costs and benefits of adding biomarker collection to population-based surveys. A crucial question is whether biomarkers offer incremental value beyond self-reported measures, which are easier to collect and impose less respondent burden. We use longitudinal data from a nationally representative sample of older Taiwanese (n = 639, aged 54+ in 2000, examined in 2000 and 2006 with mortality follow-up through 2011) to address that question with respect to predicting all-cause mortality. A summary measure of biomarkers improves mortality prediction (as measured by the area under the receiver operating characteristic curve) compared with self-reports alone, but individual biomarkers perform better than the summary score. We find that incorporating change in biomarkers over a six-year period yields a small improvement in mortality prediction compared with one-time measurement. But, is the incremental value worth the costs?

Predicting all-cause and cause-specific mortality by static and dynamic measurements of allostatic load: a 10-year population-based cohort study in Taiwan

OBJECTIVE

To evaluate the role of allostatic load (AL), either static or dynamic measurements, in predicting all-cause and cause-specific mortality of older people in Taiwan.

DESIGN

A prospective cohort study.

SETTING

Population-based community study.

PARTICIPANTS

One thousand twenty-three community-dwelling older people.

MEASUREMENTS

Allostatic load (calculated by systolic blood pressure, diastolic blood pressure, total cholesterol, high-density lipoprotein cholesterol, triglyceride, glycosylated hemoglobin, fasting glucose, waist-to-hip ratio, body mass index, dehydroepiandrosterone sulfate, insulin-like growth factor-1, 12-hour urine cortisol, 12-hour urine epinephrine, 12-hour urine norepinephrine, 12-hour urine dopamine, white blood cell count, neutrophils, interleukin-6, albumin, creatinine) and all-cause and cause-specific mortality from national death registry.

INTERVENTION

None.

RESULTS

Adjusted for age and sex, each 1-point increase in AL score was associated with 20% incremental risk of mortality [hazard ratio 1.20, 95% confidence interval (CI) 1.09-1.31]. This association can be extended to cause-specific mortality in both sexes in general. In addition, the higher AL score quintile was significantly associated with higher risk of 10-year all-cause mortality (P < .0001). This association was consistent across different cause-specific mortality (ie, malignant neoplasm (P = .008), cardiometabolic diseases (P < .0001), infectious diseases (P < .0001), respiratory diseases (P < .0001), and others (P = .0002), respectively. Compared with AL score decliners, adjusted for age, sex, and baseline AL score in 2000, participants with fast increase had significantly higher mortality (HR 2.68, 95% CI 1.23-5.84, P = .01). The effect was stronger in men (HR 2.83, 95% CI 1.1-7.29, P = .03 in slow increase; HR 4.06, 95% CI 1.56-10.6, P = .001 in fast increase group), but it was insignificant in female participants.

CONCLUSIONS

Higher AL score or rapid increase of AL score significantly increased subsequent mortality risk in older adults, either measured statically or dynamically. AL is predictive of 10-year mortality regardless of cause of death, and rapid increase in AL score is associated with higher subsequent mortality.

Allostatic load as a tool for monitoring physiological dysregulations and comorbidities in patients with severe mental illnesses

Severe mental illnesses like schizophrenia and bipolar disorder are disabling, chronic conditions that are often accompanied by medical comorbidities. In this theoretical article, we review the allostatic load model representing the "wear and tear" that chronic stress exacts on the brain and body. We propose an innovative way of monitoring physical and psychiatric comorbidities by integrating the allostatic load model into clinical practice. By interpreting peripheral biomarkers differently, medical professionals can calculate a simple, count-based, allostatic load index known to predict diverse stress-related pathologies. In addition to screening for comorbidities, allostatic load indices can be used to monitor the effects of pharmacological and psychosocial interventions. This framework can also be used to generate a dialogue between patient and practitioner to promote preventive and proactive approaches to health care.

Cross-sectional changes in patterns of allostatic load among persons with varying disabilities, NHANES: 2001-2010

BACKGROUND

Allostatic Load (AL) is a measure of physiological stress that correlates with morbidity and mortality.

OBJECTIVE

The purpose of this study was to evaluate patterns of AL among persons with each of eight categories of disability versus persons with no disabilities over the 10-year Healthy People 2010 examination period.

METHODS

The study examined measures of AL from the 2001-2010 National Health and Nutrition Examination Survey (NHANES). The independent variable was Disability Status (hearing, vision, memory, physical-mental-emotional, walking up 10 steps, bending or kneeling, lifting or carrying, assistive devices, no disability). Eight laboratory and one social AL dependent variables included blood pressure, body mass index (BMI), HDL cholesterol, number of friends, and neutrophil percentages. Weighted statistical analyses included one-way ANCOVA with age as the covariate and chi-square tests.

RESULTS

Among respondents, 2.3% had hearing disabilities; 14.0% vision disabilities, 4.6% memory disabilities; 1.5% physical, mental, emotional disabilities; 1.3%, 5.9%, and 3.5% various mobility disabilities; and 5.3% used assistive devices. Persons with disabilities had significantly higher BMI, lower HDL cholesterol, higher C-reactive protein, and higher neutrophil levels than persons without disabilities. Systolic and diastolic blood pressures decreased during the decade, but BMI increased. A range of 36.2-61.0% of persons with non-hearing disabilities exceeded BMI obesity thresholds during 2009, and 13.8-29.9% had fewer than three friends during 2009.

CONCLUSIONS

These findings support previous research linking risks for secondary conditions/morbidity and allostatic load while demonstrating associations between disabilities and AL, especially for persons with mobility disabilities.

Allostatic load in parents of children with developmental disorders: moderating influence of positive affect

This study examines whether parents of children with developmental disorders are at risk of elevated allostatic load relative to control parents and whether positive affect moderates difference in risk. In all, 38 parents of children with developmental disorders and 38 matched comparison parents were analyzed. Regression analyses revealed a significant interaction between parent status and positive affect: parents of children with developmental disorders had lower allostatic load when they had higher positive affect, whereas no such association was evident for comparison parents. The findings suggest that promoting greater positive affect may lower health risks among parents of children with developmental disorders.

Factor structure underlying components of allostatic load

Allostatic load is a commonly used metric of health risk based on the hypothesis that recurrent exposure to environmental demands (e.g., stress) engenders a progressive dysregulation of multiple physiological systems. Prominent indicators of response to environmental challenges, such as stress-related hormones, sympatho-vagal balance, or inflammatory cytokines, comprise primary allostatic mediators. Secondary mediators reflect ensuing biological alterations that accumulate over time and confer risk for clinical disease but overlap substantially with a second metric of health risk, the metabolic syndrome. Whether allostatic load mediators covary and thus warrant treatment as a unitary construct remains to be established and, in particular, the relation of allostatic load parameters to the metabolic syndrome requires elucidation. Here, we employ confirmatory factor analysis to test: 1) whether a single common factor underlies variation in physiological systems associated with allostatic load; and 2) whether allostatic load parameters continue to load on a single common factor if a second factor representing the metabolic syndrome is also modeled. Participants were 645 adults from Allegheny County, PA (30–54 years old, 82% non-Hispanic white, 52% female) who were free of confounding medications. Model fitting supported a single, second-order factor underlying variance in the allostatic load components available in this study (metabolic, inflammatory and vagal measures). Further, this common factor reflecting covariation among allostatic load components persisted when a latent factor representing metabolic syndrome facets was conjointly modeled. Overall, this study provides novel evidence that the modeled allostatic load components do share common variance as hypothesized. Moreover, the common variance suggests the existence of statistical coherence above and beyond that attributable to the metabolic syndrome.

A Systematic Review of Allostatic Load, Health, and Health Disparities

The theoretical constructs of allostasis and allostatic load (AL) have contributed to our understanding of how constantly changing social and environmental factors impact physiological functioning and shape health and aging disparities, particularly along socioeconomic, gendered, racial, and ethnic lines. AL represents the cumulative dysregulation of biological systems with prolonged or poorly regulated allostatic responses. Nearly two decades of empirical research has focused on operationalizing the AL construct for examining the antecedents and health outcomes accompanying multisystem biological dysregulation. The purpose of this systematic review is to examine the empirical literature that quantifies the AL construct; the review also evaluates the social, environmental, and genetic antecedents of AL as well as its predictive utility for a variety of health outcomes. A total of 58 articles published between 1997 and 2012 were retrieved, analyzed, and synthesized. The results revealed considerable heterogeneity in the operationalization of AL and the measurement of AL biomarkers, making interpretations and comparisons across studies challenging. There is, however, empirical substantiation for the relationships between AL and socioeconomic status, social relationships, workplace, lifestyle, race/ethnicity, gender, stress exposure, and genetic factors. The literature also demonstrated associations between AL and physical and mental health and all-cause mortality. Targeting the antecedents of AL during key developmental periods is essential for improving public health. Priorities for future research include conducting prospective longitudinal studies, examining a broad range of antecedent allostatic challenges, and collecting reliable measures of multisystem dysregulation explicitly designed to assess AL, at multiple time points, in population-representative samples.

Predicting mortality with biomarkers: a population-based prospective cohort study for elderly Costa Ricans

Background

Little is known about adult health and mortality relationships outside high-income nations, partly because few datasets have contained biomarker data in representative populations. Our objective is to determine the prognostic value of biomarkers with respect to total and cardiovascular mortality in an elderly population of a middle-income country, as well as the extent to which they mediate the effects of age and sex on mortality.

Methods

This is a prospective population-based study in a nationally representative sample of elderly Costa Ricans. Baseline interviews occurred mostly in 2005 and mortality follow-up went through December 2010. Sample size after excluding observations with missing values: 2,313 individuals and 564 deaths. Main outcome: prospective death rate ratios for 22 baseline biomarkers, which were estimated with hazard regression models.

Results

Biomarkers significantly predict future death above and beyond demographic and self-reported health conditions. The studied biomarkers account for almost half of the effect of age on mortality. However, the sex gap in mortality became several times wider after controlling for biomarkers. The most powerful predictors were simple physical tests: handgrip strength, pulmonary peak flow, and walking speed. Three blood tests also predicted prospective mortality: C-reactive protein (CRP), glycated hemoglobin (HbA1c), and dehydroepiandrosterone sulfate (DHEAS). Strikingly, high blood pressure (BP) and high total cholesterol showed little or no predictive power. Anthropometric measures also failed to show significant mortality effects.

Conclusions

This study adds to the growing evidence that blood markers for CRP, HbA1c, and DHEAS, along with organ-specific functional reserve indicators (handgrip, walking speed, and pulmonary peak flow), are valuable tools for identifying vulnerable elderly. The results also highlight the need to better understand an anomaly noted previously in other settings: despite the continued medical focus on drugs for BP and cholesterol, high levels of BP and cholesterol have little predictive value of mortality in this elderly population.

Neighborhood context and social disparities in cumulative biological risk factors

OBJECTIVE

This study examines the role of neighborhood context in the accumulation of biological risk factors and racial/ethnic and socioeconomic disparities.

METHODS

Data came from face-to-face interviews and blood sample collection on a probability sample of adults (n = 549) in the 2002 Chicago Community Adult Health Study. Following the approach of prior studies, we constructed an index of cumulative biological risk (CBR) by counting how many of eight biomarkers exceeded clinically defined criteria for "high risk": systolic and diastolic blood pressure, resting heart rate, hemoglobin A(1c), C-reactive protein, waist size, and total and high-density lipoprotein cholesterol. Data are presented as incidence rate ratios (IRRs) based on generalized linear models with a Poisson link function and population-average estimates with robust standard errors.

RESULTS

Non-Hispanic blacks (n = 200), Hispanics (n = 149), and people with low (n = 134) and moderate (n = 275) level of education had significantly higher numbers of biological risks than their respective reference groups (IRR = 1.48, 1.59, 1.62, and 1.48, respectively, with p < .01). Black-white (p < .001) and Hispanic-white (p < .003) disparities in CBR remained significant after adjusting for individual-level socioeconomic position and behavioral factors, whereas individual-level controls substantially diminished the low/high (p < .069) and moderate/high (p < .042) educational differences. Estimating "within-neighborhood" disparities to adjust for neighborhood context fully explained the black-white gap in CBR (p < .542) and reduced the Hispanic-white gap to borderline significance (p < .053). Neighborhood affluence predicted lower levels of CBR (IRR = 0.82, p < .027), but neighborhood disadvantage was not significantly associated with CBR (IRR = 1.00, p < .948).

CONCLUSIONS

Neighborhood environments seem to play a pivotal role in the accumulation of biological risk and disparities therein.

A transdisciplinary perspective of chronic stress in relation to psychopathology throughout life span development

The allostatic load (AL) model represents an interdisciplinary approach to comprehensively conceptualize and quantify chronic stress in relation to pathologies throughout the life cycle. This article first reviews the AL model, followed by interactions among early adversity, genetics, environmental toxins, as well as distinctions among sex, gender, and sex hormones as integral antecedents of AL. We next explore perspectives on severe mental illness, dementia, and caregiving as unique human models of AL that merit future investigations in the field of developmental psychopathology. A complimenting transdisciplinary perspective is applied throughout, whereby we argue that the AL model goes beyond traditional stress–disease theories toward the advancement of person-centered research and practice that promote not only physical health but also mental health.

Plasma concentrations of pro- and anti-inflammatory cytokines and outcome prediction in elderly hip fracture patients

BACKGROUND

Hip fractures, particularly intertrochanteric fractures, frequently occur in the elderly, and they are associated with a high incidence of complications and mortality. The development of markers is essential to allow for adjustments to treatment strategies in patients, as it remains unclear why some patients endure organ failure and others do not under seemingly similar clinical conditions.

OBJECTIVE

Our objective was to determine the kinetics of tumour necrosis factor (TNF)-a, interleukin (IL)-6 and IL-10 during the hospitalisation of patients and to examine the relationship of these parameters to outcome (mortality and complications) 6 months and 12 months postoperatively.

METHODS AND SUBJECTS

A total of 127 elderly patients, who underwent hip fracture surgery, were prospectively followed up for 12 months, and 60 healthy elderly volunteers were enrolled in the control group to examine the effects of trauma and surgery on the inflammatory response. The epidemiological characteristics, chronic medical conditions and type of operation and anaesthetic were recorded. Cognition was evaluated using the Mini-Mental State Examination, and TNF-a, IL-6 and IL-10 levels were assessed during admission and preoperatively (post-anaesthesia) as well as 1 h, 1 day, 3 days and 5 days postoperatively. During the follow-up period, serious complications and mortality within 1 year were evaluated.

RESULTS

Overall, 96 patients survived, and 31 died within the 6-month postoperative period; 43 patients died, and 84 survived when examining the 12-month postoperative period. There were significant within-subject effects of time on TNF-a, IL-6 and IL-10 (P<0.001, P<0.001 and P<0.001). The above three cytokines were all significantly increased in the hip fracture patients compared with the control group. There were also differences in the kinetic patterns of all three parameters when the patients who died were compared with those who survived during the 6-month and 12-month postoperative periods. Multiple logistic regression analysis showed that TNF-a at 1 day (odds ratio (OR)=1.020, P=0.045) and 3 days (OR=1.034, P=0.037) postoperatively and IL-6 at 1 day (OR=1.048, P=0.000) postoperatively were independent predictors of mortality at 6 months; IL-6 (OR=1.019, P=0.025) and IL-10 (OR=1.018, P=0.042) at 1 day postoperatively were independent predictors of mortality at 1 year. The analysis of the receiver operating characteristics curve (ROC) showed that only IL-6 or IL-10 had the highest values for the area under the curve for mortality at 6 months and 12 months. Of the 84 patients who survived, 23 patients had 32 complications. The most common complication was pneumonia infection (11/84, 13%). TNF-a, IL-6 and IL-10 kinetics were found to differ in patients with complications compared to those without complications and in patients with infections compared with patients without complications. Multiple logistic regression analysis showed that IL-6 (OR=1.081, P=0.000) at 1 day postoperatively was an independent outcome predictor.

CONCLUSION

In elderly hip fracture patients, cytokine concentrations (TNF-a, IL-6 and IL-10) represented independent outcome predictors for adverse postoperative outcomes (mortality and complications). The inflammatory response played an important role in postoperative organ dysfunction in elderly hip fracture patients, and further study is needed to define whether decreasing the inflammatory response through cytokine antibodies or damage control strategies would decrease mortality and complication following hip fracture.

Biodemography: new approaches to understanding trends and differences in population health and mortality

The incorporation of biological information in large population surveys has expanded demographic analysis to clarify the meaning of observed trends and differences in population health and mortality. Levels of measured biological risk in the population were reduced in recent years largely because of the expanded use of prescription drugs. The increased use of antihypertensives and, to a lesser extent, lipid-lowering drugs was a likely cause of significant mortality reduction. Blacks and persons with lower educational attainment experience higher levels of biological risk factors, more diseases, and more frailty; these differences are the sources of higher mortality for these groups. Hispanics are less likely to have a higher prevalence of risk factors and diseases than the non-Hispanic population, providing further understanding of the "Hispanic paradox." Almost every examined indicator of biological risk, disease, and frailty is related to higher mortality, indicating how incorporation of this information provides a fuller understanding of the morbidity process.

Improving mortality prediction using biosocial surveys

The authors used data from a nationally representative survey of 933 adults aged 54 years or older (mean age = 66.2 years; standard deviation, 8.0) in Taiwan to explore whether mortality prediction at older ages is improved by the use of 3 clusters of biomarkers: 1) standard cardiovascular and metabolic risk factors; 2) markers of disease progression; and 3) nonclinical (neuroendocrine and immune) markers. They also evaluated the extent to which these biomarkers account for the female advantage in survival. Estimates from logistic regression models of the probability of dying between 2000 and 2006 (162 deaths; mean length of follow-up = 5.8 years) showed that inclusion of each of the 3 sets of markers significantly (P = 0.024, P = 0.002, and P = 0.003, respectively) improved discriminatory power in comparison with a base model that adjusted for demographic characteristics, smoking, and baseline health status. The set of disease progression markers and the set of nonclinical markers each provided more discriminatory power than standard risk factors. Most of the excess male mortality resulted from the men being more likely than women to smoke, but each of 3 markers related to disease progression or inflammation (albumin, neutrophils, and interleukin-6) explained more than 10% of excess male mortality.

Immunity, trauma and the elderly

It is believed that an uncontrolled or poorly coordinated immune reaction can be stimulated by major trauma and be responsible for the development of the multiple organ dysfunction syndrome (MODS). The elderly have a reduced ability to mount an effective immune reaction with deficiencies involving both humoral and cellular aspects of immunity that involve poor function of both the stimulatory and immuno-suppressive sides of the immune process. However, there is currently no hard evidence that the excess mortality after major trauma in the elderly is associated with an impaired or excessive immune response. It is possible that their poor resistance to infection is important and immune modulated but the dominant factor in the excess mortality in the elderly population is probably associated with their lack of physiological reserve to respond to a major physiological challenge.