Relationship of Serum Vitamin D Concentrations and Allostatic Load as a Measure of Cumulative Biological Risk among the US Population: A Cross-Sectional Study

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.

Associations between allostatic load and hepatic steatosis and liver fibrosis: evidence from NHANES 2017-2020

BACKGROUND

Allostatic load, the cumulative strain resulting from chronic stress responses, has been linked to disease occurrence and progression, yet research quantifying this relationship is limited. This study aimed to explore the relationship between allostatic load score (ALS) levels and the degree of hepatic steatosis and fibrosis.

METHODS

Data from the National Health and Nutrition Examination Survey 2017-2020 were analyzed. The ALS was based on the statistical distribution, assigning one point for each biomarker if it was in the highest risk quartile, and then summing them to generate the ALS score (range, 0-8). The multivariate linear regression was employed to analyze the association between the controlled attenuation parameter (CAP) and liver stiffness measurement (LSM) with ALS. Additionally, multinomial logistic regression was used to investigate the association between ALS and the degree of hepatic steatosis and fibrosis.

RESULTS

Participants had a weighted mean age of 52.69 years and 56.14% were female. In the multivariate linear regression analysis, ALS showed a significant positive correlation with CAP (β = 15.56, 95% CI: 14.50-16.62) and LSM (β = 0.58, 95% CI: 0.48-0.67). Age, healthy dietary level, and PIR had significant interactions with this positive correlation. In the multinomial logistic regression analysis, ALS exhibited a significant positive correlation with different degrees of hepatic steatosis and fibrosis. Consistency of the results was observed in sensitivity analyses using clinical thresholds of ALS.

CONCLUSIONS

Comprehensive clinical assessment targeting load adaptation may enhance the effectiveness of risk assessment in patients with hepatic steatosis and fibrosis.

Association of Occupational and Leisure-Time Physical Activity With Allostatic Load

INTRODUCTION

Leisure-time physical activity decreases allostatic load, a measure of burden of chronic stress. However, the role of occupational physical activity is unknown. This study examined associations of occupational physical activity and leisure-time physical activity with allostatic load among workers in the U.S.

METHODS

This cross-sectional study included 6,944 U.S. workers aged 20-64 years from the National Health and Nutrition Examination Survey (2007-2018). Physical activity was assessed using the Global Physical Activity Questionnaire. Allostatic load was calculated using biomarkers of cardiovascular, metabolic, and immune systems. Associations of occupational physical activity and leisure-time physical activity with allostatic load were examined using negative binomial regressions. Analyses were conducted between August 2022 and March 2023.

RESULTS

Vigorous leisure-time physical activity inversely associated with allostatic load among all workers (count ratio=0.68, 95% CI=0.62, 0.76) and in each sex- and age-stratified group as well as in each race/ethnicity-stratified group. Vigorous occupational physical activity positively associated with allostatic load only among females aged 20-44 years (1.38, 95% CI=1.10, 1.73). Inverse associations of vigorous leisure-time physical activity with allostatic load were similar in young females with high or low vigorous occupational physical activity.

CONCLUSIONS

Increasing vigorous leisure-time physical activity associates with a lower allostatic load for all workers, whereas increasing vigorous occupational physical activity associates with a higher allostatic load only in young females. Promoting vigorous leisure-time physical activity reduces allostatic load among young females with either low or high vigorous occupational physical activity.

The Role of BMI in Allostatic Load and Risk of Cancer Death

INTRODUCTION

Obesity and proinflammatory conditions are associated with increased risks of cancer. The associations of baseline allostatic load with cancer mortality and whether this association is modified by body mass index (BMI) were examined.

METHODS

A retrospective analysis was performed in March-September 2022 using National Health and Nutrition Examination Survey years 1988 through 2010 linked with the National Death Index through December 31, 2019. Fine and Gray Cox proportional hazard models were stratified by BMI status to estimate subdistribution hazard ratios of cancer death between high and low allostatic load status (adjusted for age, sociodemographics, and health factors).

RESULTS

In fully adjusted models, high allostatic load was associated with a 23% increased risk of cancer death (adjusted subdistribution hazard ratio=1.23; 95% CI=1.06, 1.43) among all participants, a 3% increased risk of cancer death (adjusted subdistribution hazard ratio=1.03; 95% CI=0.78, 1.34) among underweight/healthy weight adults, a 31% increased risk of cancer death (adjusted subdistribution hazard ratio=1.31; 95% CI=1.02, 1.67) among overweight adults, and a 39% increased risk of death (adjusted subdistribution hazard ratio=1.39; 95% CI=1.04, 1.88) among obese adults, when compared to those with low allostatic load.

CONCLUSIONS

The risk of cancer death is highest among those with high allostatic load and obese BMI, but this effect was attenuated among those with high allostatic load and underweight/healthy or overweight BMI.

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.

Hearing Impairment and Allostatic Load in Older Adults

Importance

Allostatic load, the cumulative strain that results from the chronic stress response, is associated with poor health outcomes. Increased cognitive load and impaired communication associated with hearing loss could potentially be associated with higher allostatic load, but few studies to date have quantified this association.

Objective

To investigate if audiometric hearing loss is associated with allostatic load and evaluate if the association varies by demographic factors.

Design, Setting, Participants

This cross-sectional survey used nationally representative data from the National Health and Nutrition Examination Survey. Audiometric testing was conducted from 2003 to 2004 (ages 20-69 years) and 2009 to 2010 (70 years or older). The study was restricted to participants aged 50 years or older, and the analysis was stratified based on cycle. The data were analyzed between October 2021 and October 2022.

Exposure

A 4-frequency (0.5-4.0 kHz) pure tone average was calculated in the better-hearing ear and modeled continuously and categorically (<25 dB hearing level [dB HL], no hearing loss; 26-40 dB HL, mild hearing loss; ≥41 dB HL, moderate or greater hearing loss).

Main Outcome and Measures

Allostatic load score (ALS) was defined using laboratory measurements of 8 biomarkers (systolic/diastolic blood pressure, body mass index [calculated as weight in kilograms divided by height in meters squared], and total serum and high-density lipoprotein cholesterol, glycohemoglobin, albumin, and C-reactive protein levels). Each biomarker was assigned a point if it was in the highest risk quartile based on statistical distribution and then summed to yield the ALS (range, 0-8). Linear regression models adjusted for demographic and clinical covariates. Sensitivity analysis included using clinical cut points for ALS and subgroup stratification.

Results

In 1412 participants (mean [SD] age, 59.7 [5.9] years; 293 women [51.9%]; 130 [23.0%] Hispanic, 89 [15.8%] non-Hispanic Black, and 318 [55.3%] non-Hispanic White individuals), a modest association was suggested between hearing loss and ALS (ages 50-69 years: β = 0.19 [95% CI, 0.02-0.36] per 10 dB HL; 70 years or older: β = 0.10 [95% CI, 0.02-0.18] per 10 dB HL) among non-hearing aid users. Results were not clearly reflected in the sensitivity analysis with clinical cut points for ALS or modeling hearing loss categorically. Sex-based stratifications identified a stronger association among male individuals (men 70 years or older: β = 0.22 [95% CI, 0.12-0.32] per 10 dB HL; women: β = 0.08 [95% CI, -0.04 to 0.20] per 10 dB HL).

Conclusion and Relevance

The study findings did not clearly support an association between hearing loss and ALS. While hearing loss has been shown to be associated with increased risk for numerous health comorbidities, its association with the chronic stress response and allostasis may be less than that of other health conditions.

Investigating the Joint Effect of Allostatic Load among Lesbian, Gay, and Bisexual Adults with Risk of Cancer Mortality

Sexual minorities (SM) have higher chronic physiologic stress as indicated by allostatic load (AL), which may be explained in part by consistent experiences of discriminatory practices. This is one of the first studies to examine the joint effects of SM status and AL on the association with long-term risk for cancer death. Retrospective analyses were conducted on 12,470 participants using National Health and Nutrition Examination Survey (NHANES) from years 2001 through 2010 linked with the National Death Index through December 31, 2019. Cox proportional hazards models estimated adjusted hazard ratios (aHRs) of cancer deaths between groups of SM (those reporting as gay, lesbian, bisexual, or having same-sex sexual partners) status and AL. SM adults living with high AL (n = 326) had a 2-fold increased risk of cancer death (aHR: 2.55, 95% CI: 1.40-4.65) when compared to straight/heterosexual adults living with low AL (n = 6674). Among those living with high AL, SM (n = 326) had a 2-fold increased risk of cancer death (aHR: 2.26, 95% CI: 1.33-3.84) when compared to straight/heterosexual adults with high AL (n = 4957). SM with high AL have an increased risk of cancer mortality. These findings highlight important implications for promoting a focused agenda on cancer prevention with strategies that reduce chronic stress for SM adults.

Understanding the relationship between perceived discrimination, allostatic load, and all-cause mortality in US older adults: A mediation analysis

OBJECTIVE

To understand the relationship between perceived discrimination, allostatic load, and all-cause mortality; and to determine whether allostatic load is a mediator in the relationship between perceived discrimination and all-cause mortality among an older adult US population.

METHODS

Data from the Health and Retirement Study (2006-2012) was analyzed. Cox proportional hazard models were used to investigate the relationship between all-cause mortality and perceived discrimination, and all-cause mortality and allostatic load. Linear regression models were used to investigate the relationship between perceived discrimination and allostatic load. A mediation model with perceived discrimination and allostatic loads as independent variables was used to determine the association with all-cause mortality.

RESULTS

There were 5062 adults over the age of 50 included in the analysis. The relationship between perceived discrimination and allostatic load was statistically significant (b:0.14, [95%CI 0.10,0.19]; p < 0.001). The relationship between perceived discrimination and all-cause mortality was statistically significant (HR: 1.12, [95%CI 1.03,1.22]; p = 0.01). The relationship between allostatic load and all-cause mortality was statistically significant (HR: 1.11, [95%CI 1.08,1.13]; p < 0.001). The mediation model resulted in a decrease in hazard ratio and loss of statistical significance for perceived discrimination (HR: 1.09, [95%CI 0.98,1.21]; p = 0.13) when allostatic load (HR: 1.17, [95%CI 1.10,1.24]; p < 0.001) was added to the Cox regression model, indicating full mediation.

CONCLUSIONS

Allostatic load fully mediates the relationship between perceived discrimination and all-cause mortality. Understanding the role of allostatic load in this relationship provides an additional implication for screening and indications for tighter control of the modifiable components of allostatic load by healthcare providers, especially among individuals who experience discrimination.

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. AL correlates with poorer health outcomes and increased risk of cancer death. However, research indicates AA women with a college degree or higher have lower AL than AA women with less than a high school diploma. We examined whether educational attainment differences and AL status in AA women are associated with long-term risk of cancer mortality. Methods We performed a retrospective analysis among 4,677 AA women respondents using National Health and Nutrition Examination Survey (NHANES) data from 1988 through 2010 with follow up data through December 31, 2019. We fit Cox proportional hazards models to estimate adjusted hazard ratios (aHRs) of cancer death between educational attainment/AL (adjusted for age, sociodemographic, and health factors). 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: 1.24â€"7.15) of cancer death compared to AA college graduates living with low AL. However, after adjusting for age, the increased risk of cancer death in those with less than a high school diploma and high AL attenuated (age-adjusted HR: 1.11; 95% CI: .45-2.74). Conclusions Differences in educational attainment and AL in AA women were not associated with increased risk of cancer mortality when adjusted for age. Previous studies have shown that increased allostatic load is associated with increased risk of cancer death. However, for African American women, higher educational attainment does not modify the risk of cancer mortality. The benefits that may come along with higher education such as increased access to medical care and better medical literacy do not change the risk of cancer mortality in AA women.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Allostatic Load and Adverse Pregnancy Outcomes

OBJECTIVE

To assess the association between allostatic load, as an estimate of chronic stress, and adverse pregnancy outcomes.

METHODS

This was a secondary analysis of nuMoM2b (Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be), a prospective observational cohort study. Our primary exposure was dichotomous high allostatic load in the first trimester, defined as 4 or more of 12 biomarkers in the "worst" quartile. The primary outcome was a composite adverse pregnancy outcome: hypertensive disorders of pregnancy (HDP), preterm birth, small for gestational age (SGA), and stillbirth. Secondary outcomes included components of the composite. Multivariable logistic regression was used to test the association between high allostatic load and adverse pregnancy outcomes, adjusted for potential confounders. Mediation and moderation analyses were conducted to assess the role of allostatic load along the causal pathway between racial disparities and adverse pregnancy outcomes.

RESULTS

Among 4,266 individuals, 34.7% had a high allostatic load. Composite adverse pregnancy outcome occurred in 1,171 (27.5%): 14.0% HDP, 8.6% preterm birth (48.0% spontaneous and 52.2% indicated), 11.0% SGA, and 0.3% stillbirth. After adjustment for maternal age, gravidity, smoking, bleeding in the first trimester, and health insurance, high allostatic load was significantly associated with a composite adverse pregnancy outcome (adjusted odds ratio [aOR] 1.5, 95% CI 1.3, 1.7) and HDP (aOR 2.5, 95% CI 2.0-2.9), but not preterm birth or SGA. High allostatic load partially mediated the association between self-reported race and adverse pregnancy outcomes. The association between allostatic load and HDP differed by self-reported race, but not for a composite adverse pregnancy outcome, preterm birth, or SGA.

CONCLUSION

High allostatic load in the first trimester is associated with adverse pregnancy outcomes, particularly HDP. Allostatic load was a partial mediator between race and adverse pregnancy outcomes. The association between allostatic load and HDP differed by self-reported race.

A multi-center study on the association between serum magnesium levels and allostatic load in hemodialysis patients

Objective: Serum magnesium (Mg²⁺) levels are associated with insulin resistance, hypertension, lipid abnormalities, and inflammation. However, limited studies have indicated the relationship between Mg²⁺ and multiple system indexes. The purpose of this study was to investigate the association between Mg²⁺ and allostatic load (AL) in hemodialysis patients.

Methods: A cross-sectional survey was conducted on hemodialysis patients from different centers in Anhui Province, China, between January and December 2020. A total of 3,025 hemodialysis patients were recruited. Their clinical data were measured before hemodialysis. Information was collected by an online self-reported questionnaire and medical record. Serum Mg²⁺ was divided into three groups by tertiles. A score of AL greater than or equal to 3 was defined as high AL. A binary logistic regression model was applied to examine the relationship between serum Mg²⁺ and AL.

Results: A total of 1,222 patients undergoing hemodialysis were included, 60% of whom were males (733/1,222). The mean (standard deviation) age of patients was 55.90 (12.75). The median level of serum Mg²⁺ was 1.22 mmol/L. The rate of high AL levels was 23.4%. Serum Mg²⁺ was negatively correlated with body mass index, fasting blood glucose (Glu), and C-reactive protein and positively correlated with high-density lipoprotein, low-density lipoprotein, total cholesterol, diastolic blood pressure (DBP), and serum phosphorus. After adjusting for gender, anxiety, diabetes, family residence, lipid-lowering agents, antihypertensive medications, albumin, and Glu, the binary logistic regression model showed that patients with lower levels of serum Mg²⁺ were more likely have high AL (OR for the T1 group of serum Mg²⁺:1.945, 95% CI: 1.365–2.773, and OR for the T2 group of serum Mg²⁺:1.556, 95% CI: 1.099–2.201).

Conclusion: Our data support the hypothesis that higher serum Mg²⁺ concentrations may contribute to lower health risk in hemodialysis populations. Further randomized controlled trials and cohort studies are warranted to verify whether Mg²⁺ supplementation could be part of routine examinations in hemodialysis populations.

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

Background

Methods

Results

Conclusions

Impact

•

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

•

Studies suggests that racial minorities have higher allostatic load.

•

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

•

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

•

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

The association of coffee consumption rate with serum 25-hydroxyvitamin D, non-HDL levels, and TC/HDL ratio in females with vitamin D deficiency

Objectives:

The purpose of this study was to evaluate the association of coffee consumption rate with serum 25-hydroxyvitamin D, non-high-density lipoprotein cholesterol levels, and total cholesterol to high-density lipoprotein cholesterol ratio in females with vitamin D deficiency.

Methods:

This retrospective cross-sectional study was carried out by studying the records of 270 Jordanian females aged 18–65 years with varying degrees of vitamin D deficiency. Following completion of the questionnaire regarding their anthropometric characteristics and coffee consumption rate during the preceding 3 months, the participants were required to provide blood samples for analysis to measure 25-hydroxyvitamin D and lipid profile levels including non-high-density lipoprotein cholesterol and total cholesterol to high-density lipoprotein cholesterol ratio.

Results:

The current study demonstrated that coffee consumption rate and vitamin D deficiency were significantly positively connected with the total cholesterol to high-density lipoprotein cholesterol ratio ( p = .003) in women with vitamin D deficiency. In addition, vitamin D deficiency alone correlated positively with non-high-density lipoprotein cholesterol levels and the total cholesterol to high-density lipoprotein cholesterol ratio ( p = .010) and ( p = .002), respectively.

Conclusion:

Higher coffee consumption rate among women with vitamin D deficiency significantly elevated total cholesterol to high-density lipoprotein cholesterol ratio that may increase woman’s risk of hyperlipidemia.

Energy intake and season interact to influence physiological stress load among midlife women

Allostatic load (AL) is an index that measures physiologic stress associated with chronic disease risk. One factor that may influence overall physiologic stress load and AL is energy consumption, but whether this association differs across different seasons is unknown. We tested whether energy consumption interacted with the season to influence AL in 52 mid-life (40-60 years) women from the Life in All Seasons Study. Women completed an online 24-h recall every 10 days and had components of allostatic load measured seasonally. Women were from the greater Grand Forks, ND catchment area and were followed for one year between July 2012 and July 2014. We found a significant (p = 0.01) interaction between season and energy consumption on AL. Further inspection showed that, during the summer and winter seasons, the average allostatic load rose with relatively higher energy consumption. We also observed a linear and positive association between AL and energy intake in summer (β = 0.0013 ± 0.0004; p = 0.001; r² = 0.14) and winter (β = 0.0011 ± 0.0004; p = 0.007; r² = 0.10), but not in fall or spring. These results suggest that factors associated with distinct times of the year promote or prevent the effects of higher energy consumption on physiological stress load. Since allostatic load is linked to elevated disease risk, our results provide additional information that may help to explain seasonal differences in disease risk of some women.

Allostatic Load and Its Impact on Health: A Systematic Review

INTRODUCTION

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Allostatic load and mental health: a latent class analysis of physiological dysregulation

This study explored the associations between specific profiles of biological dysregulation and mental health outcomes in a national, community sample of healthy adults in the United States. A latent class analysis of data from the Midlife Development in the United States study (n = 1,757) was conducted to determine classes of biological dysregulation. Multinomial logistic regressions of class membership were employed to determine associations with measures related to depression, including whether or not individuals had sought treatment, Center for Epidemiological Studies Depression Scale, and both the generalized distress and anhedonia subscales of the Mood and Anxiety Symptoms Questionnaire. Four classes of dysregulation emerged: baseline/low dysregulation, metabolic and inflammatory dysregulation, parasympathetic dysregulation, and SAM pathway dysregulation. Individuals who met the criteria for depression measures were more likely to be in the metabolic and immune dysregulation and parasympathetic dysregulation groups as compared to the baseline group. The results suggest that mental health outcomes, such as depression, are differentially associated with specific profiles of biological dysregulation. A more nuanced approach to profiles of dysregulation could better inform treatment decisions.Lay summaryHigher levels of allostatic load, which represents the cumulative wear and tear of exposure to stress, are associated with increased rates of depression and anhedonia. Specifically, parasympathetic dysregulation and immunometabolic dysregulation are associated with negative mental health outcomes.

Exploring the Relationship Between Substance Use and Allostatic Load in a Treatment/Research Cohort and in a US Probability Sample (NHANES 2009-2016)

Allostatic load, an operationalization for cumulative strain on physiology from adaptation (allostasis) to stress over a lifetime, can manifest as damage to cardiovascular, neuroendocrine, and metabolic systems. The concept of allostatic load may be particularly useful in research on substance-use disorders (SUDs) because SUD researchers have sought to better understand the relationship between chronic stressors and drug use. Theoretical models hold that SUDs can be conceptualized as a spiral toward a state of persistent allostasis (i.e., allostasis so persistent as to represent homeostasis at a new, unhealthy set point). Regardless of the extent to which those models are accurate, increased allostatic load could be a mechanism by which frequent drug administration increases risk for adverse outcomes. We conducted two secondary analyses to evaluate allostatic load in the context of drug use, including alcohol use, in a locally recruited sample with a high proportion of illicit substance use (N = 752) and in a nationally representative sample from the NHANES 2009-2016. We hypothesized that after controlling for age and other potential confounds, people with longer histories of drug use would have higher allostatic-load scores. Multiple regression was used to predict allostatic load from participants' drug-use histories while controlling for known confounds. In the locally recruited sample, we found that longer lifetime use of cocaine or opioids was related to increased allostatic load. In NHANES 2009-2016, we found few or no such associations. Lengthy histories of problematic non-medical substance use may facilitate more rapid increases in allostatic load than aging alone, and, together with findings from previous investigations, this finding suggests increased risk for chronic disease.

Vitamin D, sport and health: a still unresolved clinical issue

Vitamin D metabolites have a pleiotropic role in human physiology, both in static and dynamic conditions, and a lot of vitamin D-related biological effects could influence physical and sport performances in athletes. Probably due to different factors (e.g., drugs, doping, nutrition, ultraviolet B radiation exposure), in athletes a very high prevalence of vitamin D inadequacy (i.e., deficiency or insufficiency) has been observed. Vitamin D inadequacy in athletes could be associated with specific health risks and to alterations of functional capacities, potentially influencing the fine adjustment of physical performances during training and sport competitions. When risk factors for vitamin D inadequacy exist, a preventive vitamin D supplementation is indicated, and if a vitamin D inadequacy is diagnosed, its supplementation is recommended. Unfortunately, on these issues many concerns remain unresolved. Indeed, it is not clear if athletes should be classified as a special population at increased risk for vitamin D inadequacy; moreover, in comparison to the non-athletic population, it is still not clear if athletes should have different reference ranges and different optimal target levels for serum vitamin D, if they have additional health risks, and if they need different type of supplementations (doses) for prevention and/or replacement therapy. Moreover, in athletes also the abuse of vitamin D supplements for ergogenic purposes raise different ethical and safety concerns. In this review, the main physio-pathological, functional and clinical issues that relate vitamin D to the world of athletes are described.

Inflammatory Biomarkers, Microbiome, Depression, and Executive Dysfunction in Alcohol Users

Alcohol-related disorders (ARD) are highly prevalent among Latin American-Caribbean countries. Mental disorders are common comorbidities in individuals with ARD. However, the etiology of the association between ARD and mental disorders remains unclear. We examined the association of inflammatory cytokines, microbiome, and other biomakers with measures of depression, social anxiety, and executive functions. We observed a significant increase in cytokine and chemokine expression levels in saliva and plasma in the alcohol group (AG) samples. Also, the salivary bacterial composition in the AG revealed an abundance of Prevotella. Depression symptomatology was markedly higher in the AG, but social anxiety levels were negligible. AG also exhibited executive dysfunctions, which negatively correlated with increased plasma levels of pro-inflammatory cytokines and increased salivary concentrations of Prevotella bacteria. Our study suggests that chronic alcohol use correlates with executive dysfunction, immune system dysregulation, and dysbiosis of the salivary microbiota. Additional studies are needed to understand the role of the microbiome and inflammation in alcohol use and mental comorbidities.

Cardiovascular and Metabolic Risk in Women in the First Year Postpartum: Allostatic Load as a Function of Race, Ethnicity, and Poverty Status

OBJECTIVE

Allostatic load (AL) represents multisystem physiological "wear-and-tear" reflecting emerging chronic disease risk. We assessed AL during the first year postpartum in a diverse community sample with known health disparities.

STUDY DESIGN

The Eunice Kennedy Shriver National Institute for Child Health and Human Development Community Child Health Network enrolled 2,448 predominantly low-income African-American, Latina, and White women immediately after delivery of liveborn infants at ≥20 weeks' gestation, following them over time with interviews, clinical measures, and biomarkers. AL at 6 and 12 months postpartum was measured by body mass index, waist:hip ratio, blood pressure, pulse, hemoglobin A1c, high-sensitive C-reactive protein, total cholesterol and high-density lipoprotein, and diurnal cortisol slope.

RESULTS

Adverse AL health-risk profiles were significantly more prevalent among African-American women compared with non-Hispanic Whites, with Latinas intermediate. Breastfeeding was protective, particularly for White women. Complications of pregnancy were associated with higher AL, and disparities persisted or worsened through the first year postpartum.

CONCLUSION

Adverse AL profiles occurred in a substantial proportion of postpartum women, and disparities did not improve from birth to 1 year. Breastfeeding was protective for the mother.

Allostatic Load: Importance, Markers, and Score Determination in Minority and Disparity Populations

Allostatic load is a physiological measure of the cumulative burden of stress on the body assessed by markers of physiological dysregulation. It is a multisystem construct that quantifies biological risk which leads to poor health and maladaptive trajectories. In this overview, which is based on a presentation made at the Flip the Script: Understanding African American Women's Resilience in the Face of Allostatic Load meeting at Ohio State University in August 2018, we build upon previous reviews by discussing four key aspects of allostatic load, specifically its: (1) importance, (2) operationalization, (3) use in minority health and health disparities research, and (4) value in such research. Operationalized in various ways, allostatic load is composed of 10 original markers and additional markers deriving from research among minority and disparity populations. The markers represent four biological systems: (1) cardiovascular, (2) metabolic, (3) inflammatory, and (4) neuroendocrine. System-specific racial/ethnic and sex-based differences have been observed. An overall score can be determined using sample-generated or empirically derived clinically relevant cut points. In summary, allostatic load provides an overall and a body system-specific mechanistic link between exposures to stressors and health outcomes that may help explain health disparities among minority populations.

Stress Measured by Allostatic Load Score Varies by Reason for Immigration: The Africans in America Study

OBJECTIVE

Reason for immigration as a biological stress has not been studied in Africans. Our goal was to determine in African immigrants, if biological stress measured by allostatic load score (ALS) varies by reason for immigration.

METHODS

Using an ALS which had been previously developed with the National Health and Nutrition Examination Survey (NHANES) data to assess stress due to racism and nativity, ALS was calculated in 85 African immigrants (67% male, age 42 ± 10 years). For confirmation, we tested five additional ALS also built from NHANES.

RESULTS

The two reasons for immigration which consistently had the lowest ALS were family reunification and lottery winner for self and immediate family. The other reasons for immigration such as study, asylum/refugee, and work had higher ALS. As reasons for immigration with the lowest ALS promoted family unity, they were combined (group 1) and the Africans who came for other reasons were combined (group 2). ALS in group 1 vs. group 2 was 1.96 ± 1.40 vs. 2.94 ± 1.87, P = 0.03.

CONCLUSIONS

Biological stress varies by reason for immigration and appears to be mitigated by maintaining family unity. Overall, reason for immigration is an important biographical data likely to influence health.

Variation in the Calculation of Allostatic Load Score: 21 Examples from NHANES

After decades of resistance, there is now a genuine consensus that disease cannot be prevented or even successfully treated unless the role of stress is addressed alongside traditionally recognized factors such as genes and the environment. Measurement of allostatic load, which is quantified by the allostatic load score (ALS), is one of the most frequently used methods to assess the physiologic response to stress. Even though there is universal agreement that in the calculation of ALS, biomarkers from three categories should be included (cardiovascular, metabolic and immune), enormous variation exists in how ALS is calculated. Specifically, there is no consensus on which biomarkers to include or the method which should be used to determine whether the value of a biomarker represents high risk. In this perspective, we outline the approach taken in 21 different NHANES studies.