Validation of an Optimized ELISA for Quantitative Assessment of Epstein-Barr Virus Antibodies from Dried Blood Spots

Drought-compounded stress and immune function in Kenyan pastoralist boys and girls occupying contrasting climate zones

BACKGROUND AND AIM

We provide ethnographic, photovoice, and psychosocial stress data (food and water insecurity, potentially traumatic events, stress biomarkers) documenting the joys, hazards, and stressors of adolescents engaging in climate-sensitive pastoralist livelihoods in a global climate change hot spot. We aim to holistically capture socio-environmental relationships characterised by climate sensitive livelihoods and forms of precarity exacerbated by climate change.

SUBJECTS AND METHODS

Qualitative and quantitative methods were integrated to understand the embodied toll of hazards that Samburu pastoralists faced based on a sample of 161 young people. Quantitatively, we tested for associations of psychosocial stressors with both psychological distress and cell-mediated immune function (assessed through differences in IgG antibodies to Epstein-Barr virus).

RESULTS

Qualitatively, young Samburu reported drought, food and water insecurity, wildlife encounters, and war exposure. Girls overall endorsed more posttraumatic stress symptoms, although boys reported relatively more stressors; girls overall and young people in the hotter subregion manifested more immune dysregulation.

CONCLUSION

In spite of important differences between climate subregions, the common elements throughout the Samburu pastoralist leanscape include food and water insecurity and overall precarity exacerbated by drought and climate change. Community-driven interventions are needed to reduce precarity for young people pursuing pastoralist livelihoods.

Short- and long-term stability of SARS-CoV-2 antibodies on dried blood spots under different storage conditions

Dried blood spots (DBS) are broadly used for different serological analyses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody assessment. In order to biobank DBS samples, an understanding of the preservation of SARS-CoV-2 antibodies is needed. Therefore, we assessed the stability of SARS-CoV-2 antibodies on DBS during short- and long-term storage under different storage temperatures. Seven sample donors were enrolled, each donating twenty 6 mm DBS to assess anti-spike (S1) SARS-CoV-2 IgG antibodies (EUROIMMUN). Baseline samples were analyzed on the day of collection. The remainder of the samples was stored in grip seal bags kept in a cryobox at room temperature/4°C until 2 months after collection and at -20°C until 2 years after collection. Samples were analyzed at regular intervals within the total storage duration and after one and five freeze-thaw cycles. A pooled coefficient of variation was calculated for each storage temperature. We found that anti-S1 SARS-CoV-2 antibodies collected on DBS saver cards remain stable during short-term storage at RT, 4°C, and -20°C (at least to 2 months) and long-term storage at -20°C (at least 2 years). Moreover, up to five freeze-thaw cycles can occur without impacting the anti-S1 SARS-CoV-2 antibody level. The inter-assay coefficient of variation lies between 10 and 15%. As DBS can be preserved for both shorter periods of time at RT and longer periods of time at -20°C, they are a perfect application for studies that require sample shipment by mail, self-sampling studies, studies in limited resource settings and biobanking.IMPORTANCEDried blood spots (DBS) are currently widely used as a microsampling technique for different qualitative and quantitative serological assessments. Yet, there is a lack of long-term stability and storage condition studies. In our study, first, we assessed the stability of SARS-CoV-2 antibodies on DBS up to 2 years post-collection. We believe that our data are not only important for future COVID-19 research but also for studies on other infections/diseases using DBS-based serology.

Influence of Hematocrit and Storage Temperature on the Stability of Dried Blood Samples in Serological Analyses of Tetanus, Diphtheria, and Pertussis

BACKGROUND

Dried blood spots (DBSs) enable the study of serological markers of various pathogens without the need to obtain serum/plasma through venipuncture.

METHODS

Sixty-four blood samples were prepared on Whatman™ 903 cards using specimens obtained by venipuncture to study the detection of serological markers of diphtheria, tetanus, and pertussis in DBSs, and their stability 4 months post-collection. An automated chemiluminescent immunoassay was used to investigate diphtheria, tetanus, and pertussis IgG levels from both DBSs and plasma samples.

RESULTS

An optimal cut-off value for DBSs was calculated to improve the performance of diphtheria and tetanus serological markers in DBSs, achieving high sensitivity (95% and 98%, respectively) and specificity (91.7% and 92.3%, respectively). No protection against pertussis was found in the population studied. The correlation observed between the plasma and the DBSs processed after sample collection was high (0.967-0.970) for all antibodies studied except pertussis (0.753), both considering hematocrit before sample elution or not. The correlation between DBSs and plasma for diphtheria and tetanus remained strong following a 4-month delay in DBS processing at 4 °C (0.925-0.964) and -20 °C (0.924-0.966), with only a minor decrease observed for diphtheria at room temperature (0.889), while maintaining a strong correlation for tetanus (0.960). For pertussis, the correlation between DBSs and plasma was drastically reduced after delaying its processing for 4 months at any temperature.

CONCLUSIONS

To summarize, hematocrit levels within the normal range do not affect the processing of DBSs in the study of serological markers of diphtheria, tetanus, and pertussis. The DBS stability for serological diagnosis of diphtheria and tetanus is adequate when samples are stored at -20 °C for a period of 4 months. The pertussis serological marker does not appear to remain stable after 4 months, even when the DBS is stored frozen at -20 °C.

Evaluation of dried blood spots for Epstein-Barr virus nucleic acid testing

Epstein-Barr virus (EBV) is a ubiquitous and oncogenic virus that is associated with various malignancies and non-malignant diseases and EBV DNA detection is widely used for the diagnosis and prognosis prediction for these diseases. The dried blood spots (DBS) sampling method holds great potential as an alternative to venous blood samples in geographically remote areas, for individuals with disabilities, or for newborn blood collection. Therefore, the objective of this study was to assess the viability of detecting EBV DNA load from DBS. Matched whole blood and DBS samples were collected for EBV DNA extraction and quantification detection. EBV DNA detection in DBS presented a specificity of 100 %. At different EBV DNA viral load in whole blood, the sensitivity of EBV DNA detection in DBS was 38.78 % (≥1 copies/mL), 43.18 % (≥500 copies/mL), 58.63 % (≥1000 copies/mL), 71.43 % (≥2000 copies/mL), 82.35 % (≥4000 copies/mL), and 92.86 % (≥5000 copies/mL), respectively. These results indicated that the sensitivity of EBV DNA detection in DBS increased with elevating viral load. Moreover, there was good correlation between EBV DNA levels measured in whole blood and DBS, and on average, the viral load measured in whole blood was about 6-fold higher than in DBS. Our research firstly demonstrated the feasibility of using DBS for qualitative and semi-quantitative detection of EBV DNA for diagnosis and surveillance of EBV-related diseases.

Physiological and genomic signatures of war and displacement: A comprehensive literature review and future directions

There are now 108.4 million forcibly displaced people worldwide, many of whom endure adversities that result in trauma, toxic stress, and potentially, altered epigenetic development. This paper provides a comprehensive review of current literature on the biological signatures of war and forced migration among refugee populations. To consolidate evidence and identify key concerns and avenues for future research, we reviewed 36 publications and one article under review, published since 2000, most of which focused on refugees relocated in Europe and the Middle East. This body of work - including cross-sectional, observational, and experimental studies - reveals heterogenous findings regarding human biological responses to war-related adversities and their associations with health outcomes. We conclude with four main observations, regarding why genomic and physiological biomarkers are valuable, what study designs advance understanding of causality and health-promoting interventions, how to prepare for ethical challenges, and why theoretical frameworks and research procedures need more detailed consideration in scientific publications.

Refugee health and physiological profiles in transitional settlements in Serbia and Kenya: Comparative evidence for effects of gender and social support

When armed conflict compels people to flee from their homelands, they embark on protracted journeys during which they experience wide ranging physical, social, and psychological challenges. Few studies have focused on refugee psychosocial and physiological profiles during the transitional phase of forced migration that often involves temporary sheltering. Transient refugees' experiences can vary substantially based on local socio-ecological conditions in temporary settlements, including the length of stay, living conditions, as well as the availability and accessibility of physical and social resources. In this study, we compared physiological and psychosocial data from refugees (N=365; 406 observations) in Serbia and Kenya, respectively, with divergent temporal (length of stay) and socio-ecological conditions. In Serbia, refugees resided in asylum centers (mean stay: 0.9 y); in Kenya they were living in Kakuma Refugee Camp (mean stay: 8.8 y), one of the world's largest camps at the time. We had limited ability to directly compare psychosocial measures and used meta-analytic techniques to evaluate predictors of refugee mental and physical health at the two sites, including based on perceived social support. Refugees in Serbia had higher fingernail cortisol (p < 0.001) and were less likely to have elevated C-reactive protein (CRP) levels (p < 0.01) than refugees in Kakuma. We found common gender differences in both settings; women had lower cortisol but higher EBV antibody titers and higher likelihood of having elevated CRP compared to men (all p < 0.01). Woman also reported poorer mental and physical health (p < 0.001). These physiological and health differences may reflect variation between men and women in their psychosocial and physical experiences of factors such as stress, violence, and trauma during their journeys and as transitional refugees. Finally, we also found that refugees with lower levels of perceived social support reported poorer physical and mental health (p < 0.001). Although our results are cross-sectional, they suggest that this intermittent phase of the refugee experience is a key window for helping enhance refugee well-being through an emphasis on interpersonal and community support systems.

Perceived income inadequacy is associated with Epstein-Barr Virus latency and mental health outcomes in informal caregivers who are also employed in the healthcare industry

Finances are a prevalent source of stress. In a sample of 799 nursing home workers measured multiple times over 18 months, we found that higher perceived income inadequacy, the perception that one's expenses exceeds one's incomes, was associated with poorer self-reported mental health indicators and Epstein-Barr Virus antibody titers (a marker of cell-mediated immune function). Perceived income inadequacy predicted outcomes over and above the role of other socioeconomic status variables (objective household income and education). Mental health variables were not related to Epstein-Barr Virus antibody titers. Additionally, we found an interaction between perceived income inadequacy and informal caregiver status on our mental health outcomes; informal caregivers with higher perceived income inadequacy had poorer mental health than non-caregivers with the same perceived income inadequacy. Our findings may add nuance to the reserve capacity model, which states that those at lower socioeconomic levels are at higher risk of adverse health outcomes partly because they have fewer resources to address demands and strain. Perceived income inadequacy may significantly predict mental and physical well-being beyond other socioeconomic status variables, especially among lower-income employees. Caregiving stress and perceived income inadequacy may have synergistic effects on mental health.

Effect of the Hematocrit and Storage Temperature of Dried Blood Samples in the Serological Study of Mumps, Measles and Rubella

Dried blood spots (DBSs) are an economical and convenient alternative to serum/plasma, which allow for the serological and molecular study of different pathogens. Sixty-four blood samples were collected by venipuncture and spotted onto Whatman™ 903 cards to evaluate the utility of DBSs and the effect of the storage temperature for 120 days after sample collection to carry out serological diagnosis. Mumps, measles and rubella IgG were investigated from DBSs and plasma using an automated chemiluminescent immunoassay. Using a calculated optimal cut-off value, the serological evaluation of mumps, measles and rubella using DBSs achieved high sensitivity (100%, 100% and 82.5%, respectively) and specificity (100%, 87.5% and 100%, respectively). The correlation observed between the plasma and the DBSs processed after sample collection was high (0.914-0.953) for all antibodies studied, both considering hematocrit before sample elution or not. For the different storage conditions, the correlation with plasma was high at 4 °C (0.889-0.925) and at -20 °C (0.878-0.951) but lower at room temperature (0.762-0.872). Measles IgG results were more affected than other markers when DBSs were stored at any temperature for 120 days. To summarize, hematocrit does not affect the processing of DBSs in the study of serological markers of mumps, measles and rubella. DBS stability for serological diagnosis of mumps and rubella is adequate when samples are stored at -20 °C or 4 °C, but not at room temperature, for a period of 4 months.

Minimally invasive biomarkers in human and non-human primate evolutionary biology: Tools for understanding variation and adaptation

BACKGROUND

The use of minimally invasive biomarkers (MIBs - physiological biomarkers obtained from minimally invasive sample types) has expanded rapidly in science and medicine over the past several decades. The MIB approach is a methodological strength in the field of human and non-human primate evolutionary biology (HEB). Among humans and our closest relatives, MIBs provide unique opportunities to document phenotypic variation and to operationalize evolutionary hypotheses.

AIMS

This paper overviews the use of MIBs in HEB. Our objectives are to (1) highlight key research topics which successfully implement MIBs, (2) identify promising yet under-investigated areas of MIB application, and (3) discuss current challenges in MIB research, with suggestions for advancing the field.

DISCUSSION AND CONCLUSIONS

A range of MIBs are used to investigate focal topics in HEB, including energetics and life history variation/evolution, developmental plasticity, and social status and dominance relationships. Nonetheless, we identify gaps in existing MIB research on traits such as physical growth and gut function that are central to the field. Several challenges remain for HEB research using MIBs, including the need for additional biomarkers and methods of assessment, robust validations, and approaches that are standardized across labs and research groups. Importantly, researchers must provide better support for adaptation and fitness effects in hypothesis testing (e.g., by obtaining complementary measures of energy expenditure, demonstrating redundancy of function, and performing lifetime/longitudinal analyses). We point to continued progress in the use of MIBs in HEB to better understand the past, present, and future of humans and our closest primate relatives.

Age-related patterns of cytomegalovirus antibodies accompanying Epstein-Barr virus co-infection

OBJECTIVE

Cytomegalovirus (CMV) infection is associated with age-related chronic disease, and co-infection with Epstein-Barr virus (EBV) may compound disease risk. We aimed to assess the frequency of CMV infection and its relationship with age among EBV seropositive individuals in an Indigenous Amazonian population.

METHODS

We report concentrations of CMV and EBV antibodies in dried blood spot samples collected from 157 EBV positive Shuar participants aged 15-86 years (60.5% female) to assess CMV infection rate. We used logistic and linear regression models to examine associations among CMV, EBV, and age, adjusting for sex, geographic region, and body mass index.

RESULTS

Nearly two-thirds (63.1%) of EBV seropositive participants were also CMV seropositive. A 1-year increase in age was associated with 3.4% higher odds of CMV infection (OR [95% CI]: 1.034 [1.009-1.064], p = .012), but CMV antibody concentration was not significantly associated with age or EBV antibody concentration among co-infected individuals.

CONCLUSIONS

Herpesvirus-related immunosenescence may be important to understanding chronic disease risk among Shuar. Future studies should further explore the role of co-infection in shaping age-related changes in immune function.

Applying minimally invasive biomarkers of chronic stress across complex ecological contexts

Chronic stress is both theoretically and methodologically challenging to operationalize through biomarkers. Yet minimally invasive, field-friendly biomarkers of chronic stress are valuable in research linking biology and culture, seeking to understand differential patterns of human development across ecological contexts, and exploring the evolution of human sociality. For human biologists, a central question in measurement and interpretation of biomarkers is how stress-responsive physiological systems are regulated across diverse human ecologies. This article aims to describe a conditional toolkit for human biologists interested in the study of chronic stress, highlighting a mix of longstanding and novel biomarkers, with special focus on hair/fingernail cortisol, latent herpesvirus antibodies, allostatic load indices, and serial/ambulatory data collection approaches. Future trends in chronic stress biomarker research, including epigenetic approaches, are briefly considered. This overview considers: (1) challenges in separating a distinctly psychosocial dimension of chronic stress from adversity more broadly; (2) essential characteristics of human ecology that shape interpretation; (3) retrospective vs. longitudinal sampling; (4) the role of age, developmental effects, and local biologies; (5) different timescales of chronicity; and (6) the role of culture.

Current and future applications of biomarkers in samples collected through minimally invasive methods for cancer medicine and population-based research

Despite advances in cancer medicine and research, invasive and potentially risky procedures such as biopsies, venous blood tests, imaging, colonoscopy, and pap smear tests are still primarily used for screening, staging, and assessing response to therapy. The development and interdisciplinary use of biomarkers from urine, feces, saliva, scent, and capillary blood collected with minimally invasive methods represents a potential opportunity for integration with biomarker analysis for cancers, both in clinical practice (e.g., in screening, treatment, and disease monitoring, and improved quality of life for patients) and population-based research (e.g., in epidemiology/public health, studies of social and environmental determinants, and evolutionary medicine). In this article, we review the scientific rationale, benefits, challenges, and potential opportunities for measuring cancer-related biomarkers in samples collected through minimally invasive methods.

Transient refugees' social support, mental health, and physiological markers: Evidence from Serbian asylum centers

OBJECTIVES

Refugees seeking safety across international borders are often exposed to a wide breadth of psychosocially stressful experiences that may fracture existing sources of social support and impair the generation of new social relationships, with implications for their long-term health and resilience. Using data from recently settled refugees in two asylum centers in Serbia, we examined the associations between social support, mental health, and physiological markers.

METHODS

In this mixed-method study of refugees (age 18-50 years, n = 76), we collected key socio-demographic information and conducted semi-structured interviews about refugees' journey and stay in Serbia, trauma/loss, and their sources of social support. We also collected self-reported measures of mental well-being as well as physiological markers relevant to repeated exposure to chronic psychosocial stress (fingernail cortisol and dried blood spots for analysis of Epstein-Barr virus [EBV] antibody titers).

RESULTS

We found that refugees with longer journeys reported lower social support than those with shorter journeys. Refugees with lower social support reported poorer mental well-being, greater PTSD-related symptoms, and higher recent perceived stress than those with higher social support. We also observed that refugees with lower social support and higher recent stress, respectively, tended to exhibit higher fingernail cortisol levels. However, we did not observe comparable patterns linking EBV antibodies with psychosocial functioning.

CONCLUSION

Our cross-sectional findings are consistent with the notion that social support is likely to be a critical component in effective interventions aimed at mitigating the adverse health effects of relocation-related illnesses and poor social functioning as they await resettlement.

Insight into prognostics, diagnostics, and management strategies for SARS CoV-2

The foremost challenge in countering infectious diseases is the shortage of effective therapeutics. The emergence of coronavirus disease (COVID-19) outbreak has posed a great menace to the public health system globally, prompting unprecedented endeavors to contain the virus. Many countries have organized research programs for therapeutics and management development. However, the longstanding process has forced authorities to implement widespread infrastructures for detailed prognostic and diagnostics study of severe acute respiratory syndrome (SARS CoV-2). This review discussed nearly all the globally developed diagnostic methodologies reported for SARS CoV-2 detection. We have highlighted in detail the approaches for evaluating COVID-19 biomarkers along with the most employed nucleic acid- and protein-based detection methodologies and the causes of their severe downfall and rejection. As the variable variants of SARS CoV-2 came into the picture, we captured the breadth of newly integrated digital sensing prototypes comprised of plasmonic and field-effect transistor-based sensors along with commercially available food and drug administration (FDA) approved detection kits. However, more efforts are required to exploit the available resources to manufacture cheap and robust diagnostic methodologies. Likewise, the visualization and characterization tools along with the current challenges associated with waste-water surveillance, food security, contact tracing, and their role during this intense period of the pandemic have also been discussed. We expect that the integrated data will be supportive and aid in the evaluation of sensing technologies not only in current but also future pandemics.

Developing and validating a modified enzyme linked immunosorbent assay method for detecting HEV IgG antibody from dried blood spot (DBS) samples in endemic settings

Serological analysis is an integral part of laboratory practice nowadays. The present study was aimed to develop and validate a modified Enzyme linked Immunosorbent Assay (ELISA) for determination of IgG antibody against Hepatitis E Virus (HEV) using dried blood spots (DBS) and corresponding plasma samples. A total of 65 samples (45 HEV patients, 20 healthy controls) were analyzed. DBS and plasma samples demonstrated equivalent optical densities for detecting anti-HEV IgG. A highly significant correlation was observed between plasma and DBS sample absorbances (R² = 0.98; p < 0.001) at dilution 1:200, indicating true agreement between the two procedures. The assay exhibited decent linearity and showed no effect of physiological hematocrit on assay performance. Data suggested recommendable promise in using DBS as a suitable alternative to plasma samples to determine HEV IgG antibody evidenced by significant correlation with plasma results. Therefore, identical method for processing DBS specimens including it's proper storage is recommended for implementation of a modified ELISA in different settings.

Reliability of dried blood spot (DBS) cards in antibody measurement: A systematic review

BACKGROUND

Increasingly, vaccine efficacy studies are being recommended in low-and-middle-income countries (LMIC), yet often facilities are unavailable to take and store infant blood samples correctly. Dried blood spots (DBS), are useful for collecting blood from infants for diagnostic purposes, especially in low-income settings, as the amount of blood required is miniscule and no refrigeration is required. Little is known about their utility for antibody studies in children. This systematic review aims to investigate the correlation of antibody concentrations against infectious diseases in DBS in comparison to serum or plasma samples that might inform their use in vaccine clinical trials.

METHODS AND FINDINGS

We searched MEDLINE, Embase and the Cochrane library for relevant studies between January 1990 to October 2020 with no language restriction, using PRISMA guidelines, investigating the correlation between antibody concentrations in DBS and serum or plasma samples, and the effect of storage temperature on DBS diagnostic performance. We included 40 studies in this systematic review. The antibody concentration in DBS and serum/plasma samples reported a good pooled correlation, (r2 = 0.86 (ranged 0.43 to 1.00)). Ten studies described a decline of antibody after 28 days at room temperature compared to optimal storage at -20°C, where antibodies were stable for up to 200 days. There were only five studies of anti-bacterial antibodies.

CONCLUSIONS

There is a good correlation between antibody concentrations in DBS and serum/plasma samples, supporting the wider use of DBS in vaccine and sero-epidemiological studies, but there is limited data on anti-bacterial antibodies. The correct storage of DBS is critical and may be a consideration for longer term storage.

Validation of dried blood spot sample modifications to two commercially available COVID-19 IgG antibody immunoassays

Aim: Coronavirus disease 2019 antibody testing often relies on venous blood collection, which is labor-intensive, inconvenient and expensive compared with finger-stick capillary dried blood spot (DBS) collection. The purpose of our work was to determine if two commercially available anti-severe acute respiratory syndrome coronavirus 2 enzyme-linked immunosorbent assays for IgG antibodies against spike S1 subunit and nucleocapsid proteins could be validated for use with DBS. Materials & methods: Kit supplied reagents were used to extract DBS, and in-house DBS calibrators were included on every run. Results: Positive/negative concordance between DBS and serum was 100/99.3% for the spike S1 subunit assay and 100/98% for the nucleocapsid assay. Conclusion: Validation of the DBS Coronavirus disease 2019 IgG antibody assays demonstrated that serum and DBS can produce equivalent results with minimal kit modifications.

Performance of a web-based application measuring spot quality in dried blood spot sampling

Background The dried blood spot (DBS) method allows patients and researchers to collect blood on a sampling card using a skin-prick. An important issue in the application of DBSs is that samples for therapeutic drug monitoring are frequently rejected because of poor spot quality, leading to delayed monitoring or missing data. We describe the development and performance of a web-based application (app), accessible on smartphones, tablets or desktops, capable of assessing DBS quality at the time of sampling by means of analyzing a picture of the DBS. Methods The performance of the app was compared to the judgment of experienced laboratory technicians for samples obtained in a trained and untrained setting. A robustness- and user test were performed. Results In a trained setting the app yielded an adequate decision in 90.0% of the cases with 4.1% false negatives (insufficient quality DBSs incorrectly not rejected) and 5.9% false positives (sufficient quality DBSs incorrectly rejected). In an untrained setting this was 87.4% with 5.5% false negatives and 7.1% false positives. A patient user test resulted in a system usability score of 74 out of 100 with a median time of 1 min and 45 s to use the app. Robustness testing showed a repeatability of 84%. Using the app in a trained and untrained setting improves the amount of sufficient quality samples from 80% to 95.9% and 42.2% to 87.9%, respectively. Conclusions The app can be used in trained and untrained setting to decrease the amount of insufficient quality DBS samples.

C-reactive protein, Epstein-Barr virus, and cortisol trajectories in refugee and non-refugee youth: Links with stress, mental health, and cognitive function during a randomized controlled trial

Experiencing childhood adversity has been associated with significant changes in inflammation, cell-mediated immunocompetence, and cortisol secretion. Relatively few studies have examined, longitudinally, alterations to inflammatory processes during adolescence, especially outside Western contexts; none have evaluated biomarker trajectories for at-risk youth in response to a structured behavioral intervention. We conducted a randomized controlled trial evaluating the efficacy of a humanitarian intervention targeting stress-alleviation, with 12-18 year-old Syrian refugees (n = 446) and Jordanian non-refugees (n = 371) living side-by-side in war-affected communities in Jordan. We measured C-reactive protein (CRP), Epstein-Barr virus antibodies (EBV), and hair cortisol concentration (HCC) at three timepoints (pre/post intervention and 11 month follow-up), and assessed three main outcomes (psychosocial stress, mental health, and cognitive function). Using growth mixture models, regressions, and growth curve models, we identified three distinct trajectories for CRP, two for EBV, and three for HCC, and examined their associations with age, gender, BMI, poverty, and trauma. We found associations with BMI for CRP, refugee status for EBV, and BMI and gender with HCC trajectory. In terms of health outcomes, we found associations between rising CRP levels and perceived stress (B =  -2.92, p = .007), and between HCC hypersecretion and insecurity (B = 7.21, p = .017). In terms of responses to the intervention, we observed no differential impacts by CRP or EBV trajectories, unlike HCC. These results suggest that commonly-assayed biomarkers do not associate with health outcomes and respond to targeted interventions in straightforward ways. Our study is the first to examine multiple biomarker trajectories in war-affected adolescents, in order to better evaluate the extent, timing, and malleability of the biological signatures of poverty, conflict, and forced displacement.

Chronic stress and age-related pattern of blood pressure: A cross-sectional study in rural China

OBJECTIVE

Chronic stress is a risk factor for hypertension in adults. However, there is conflicting evidence for older adults. We hypothesized that age-related arterial stiffening, which leads to a lower blood pressure (especially diastolic blood pressure [DBP]), is more pronounced among older adults with high vs low stress. The objectives of this study were (a) to investigate age-related trends in systolic and DBPs among adults in rural Fujian, China, and (b) to examine differences in age-related blood pressure trends according to levels of stress by using Epstein-Barr virus (EBV) antibody titer as a marker of chronic stress status.

METHODS

We collected cross-sectional data from 764 rural community-dwelling adults in rural Fujian, China (mean age = 59.4). Participants were categorized into high and low stress groups by median split of EBV antibody titer. A least-squares regression analysis was used to investigate the association between age and blood pressures.

RESULTS

We observed an inverted U-shaped association between age and DBP, while there was a linear association between age and systolic blood pressure in the overall sample. When stratified by stress, the inverted U-shaped associations with age (both systolic and DBPs) were seen only among those with high stress; DBP peaked at the age of ~68 years, and the declining trend later in life was more clearly observed among those with high chronic stress.

DISCUSSION

Decrease of DBP was more pronounced among older adults with high vs low chronic stress in rural China.

Epigenetic aging in children from a small-scale farming society in The Congo Basin: Associations with child growth and family conflict

Developmental environments influence individuals' long-term health trajectories, and there is increasing emphasis on understanding the biological pathways through which this occurs. Epigenetic aging evaluates DNA methylation at a suite of distinct CpG sites in the genome, and epigenetic age acceleration (EAA) is linked to heightened chronic morbidity and mortality risks in adults. Consequently, EAA provides insights on trajectories of biological aging, which early life experiences may help shape. However, few studies have measured correlates of children's epigenetic aging, especially outside of the U.S. and Europe. In particular, little is known about how children's growth and development relate to EAA in ecologies in which energetic and pathogenic stressors are commonplace. We studied EAA from dried blood spots among Bondongo children (n = 54) residing in a small-scale, fisher-farmer society in a remote region of the Republic of the Congo. Here, infectious disease burdens and their resultant energy demands are high. Children who were heavier for height or taller for age, respectively, exhibited greater EAA, including intrinsic EAA, which is considered to measure EAA internal to cells. Furthermore, we found that children in families with more conflict between parents had greater intrinsic EAA. These results suggest that in contexts in which limited energy must be allocated to competing demands, more investment in growth may coincide with greater EAA, which parallels findings in European children who do not face similar energetic constraints. Our findings also indicate that associations between adverse family environments and greater intrinsic EAA were nonetheless observable but only after adjustment for covariates relevant to the energetically and immunologically demanding nature of the local ecology.

The association between family members' migration and Epstein-Barr virus antibody titers among people left behind in rural Fujian, China

OBJECTIVES

In contrast to the health of migrants, which has been extensively studied, little attention has been paid to the health of adults left behind by family members who out-migrated to other locations. This study was performed to investigate the association between being left behind and the Epstein-Barr virus (EBV) antibody titer, which is an indicator of cellular immune functioning previously shown to be associated with psychological stress.

METHODS

A cross-sectional survey was conducted in rural communities in Fujian, China, in 2015. Questionnaire data and dried blood spot samples were collected from 748 adults. A mixed effect regression analysis was conducted to investigate the association.

RESULTS

Results indicated that the EBV antibody titers were higher among people who had been left behind compared with those who had not.

CONCLUSIONS

Our findings suggest that, in rural Fujian, China, family separation following the out-migration of family members is an important determinant of psychological stress.

Association between early parental deprivation and cellular immune function among adults in rural Fujian, China

This study investigated the role of childhood parental deprivation in the association between quality of life (QOL) and the Epstein-Barr virus (EBV) antibody titer, a marker of cellular immune functioning, using data from 734 adults living in seven communities in rural Fujian, China. Parental deprivation was defined if either of their parents had died, divorced, or left them for migratory work for more than 1 year before they turned (a) 16 years of age (childhood and adolescence), or (b) 3 years of age (early childhood). A mixed-effects regression analysis with a random effects model revealed that parental deprivation during early childhood was positively associated with the EBV antibody titer (coefficient = 0.33, p = 0.007), whereas parental deprivation during the first 16 years was not. Further analysis incorporating an interaction term between QOL and parental deprivation revealed a significant interaction between QOL and parental deprivation during early childhood; a significant association between QOL and the EBV antibody titer was found only among those who reported parental deprivation during early childhood. This study suggests that parental deprivation during the period of immune system development may be linked with physiological responses to stressors later in life.

Stress and the menopausal transition in Campeche, Mexico

Background

Stress has been implicated as a factor in the presence and severity of symptoms during the menopausal transition. Our primary aim was to test the hypothesis that stress-sensitive biological measures and self-reported stress would be positively associated with a greater likelihood and intensity of hot flashes. Our secondary aim was to examine measures of stress in relation to the most often reported symptoms in Campeche, Mexico. We also hypothesized ethnic differences (Maya versus non-Maya) in relation to measures of stress and symptom reports.

Methods

Participants aged 40–60 (n = 305) were drawn from multiple sites across the city of San Francisco de Campeche to achieve a generally representative sample. Measures included C-reactive protein (CRP), an indicator of inflammation; Epstein-Barr virus antibodies (EBV-Ab), an indicator of immune function; the Perceived Stress Scale (PSS); a symptom checklist; anthropometric measures; and a questionnaire that elicited symptoms, ethnicity (based on language, birthplace, and last names of the woman, her parents, and her grandparents) and ten dimensions of socioeconomic status (SES). The relationships between symptoms and stress-sensitive biological and self-reported measures were examined in bivariate analyses, and with logistic and linear regressions.

Results

The twelve most common symptoms reported, in descending order of frequency, were tiredness, muscle and joint pain, nervous tension, problems concentrating, feeling depressed, difficulty sleeping, headaches, feeling of ants crawling on the skin, loss of interest in sex, urinary stress incontinence, hot flashes, and night sweats. PSS scores were significantly associated with the likelihood of seven symptoms (yes/no), and with the intensity of ten symptoms after controlling for ethnicity, SES, education, cohabitation status, parity, smoking, body mass index, and menopausal status. The stress-sensitive biological measures of immune function (EBV-Ab and CRP) were not significantly associated with midlife symptoms. The PSS was associated with more symptoms among the Maya (e.g., feeling nervous/tense and having difficulty concentrating) than non-Maya.

Conclusion

PSS scores were associated with the intensity, but not the likelihood, of hot flashes. Other symptoms were also associated with self-reported stress but not with physiological measures. Maya/non-Maya differences may indicate that either symptoms or stress were experienced and/or reported in culture-specific ways.

Epstein-Barr virus antibody titer as a stress biomarker and its association with social capital in rural Fujian communities, China

OBJECTIVES

There has been little research on the association between social capital and psychological stress measured by a biomarker, particularly in developing countries. Our objective was to investigate the association between Epstein-Barr virus (EBV) antibody titer, an indicator of cellular immune function previously shown to be associated with psychological stress, and social capital among rural community dwellers in Fujian Province, China.

METHODS

We conducted a cross-sectional survey in seven rural communities in Fujian in 2015. We used questionnaire data and dried blood spot samples for the measurement of biomarkers collected from 734 local residents for the analysis. We conducted a mixed effects regression analysis to investigate the association between EBV antibody titer and four social capital variables, which included cognitive and structural social capital assessed both at individual and community levels.

RESULTS

Community-level structural social capital was inversely associated with psychological stress (coefficient = -0.96, 95% confidence interval [CI] = -1.91, -0.01) while individual-level structural social capital was positively associated with it (coefficient = 0.21, 95% CI = 0.07, 0.36). Neither individual- nor community-level cognitive social capital was associated with psychological stress status.

CONCLUSIONS

In rural Fujian, China, social capital seemed to be an important determinant of psychological health. While living in a community with active social interaction may benefit the residents psychologically, social interaction in the form of strongly bonded relationships may be a source of psychological stress at the individual level due to the potential demands and obligations that may be associated with such connections.

Tradeoffs between immune function and childhood growth among Amazonian forager-horticulturalists

Immune function is an energetically costly physiological activity that potentially diverts calories away from less immediately essential life tasks. Among developing organisms, the allocation of energy toward immune function may lead to tradeoffs with physical growth, particularly in high-pathogen, low-resource environments. The present study tests this hypothesis across diverse timeframes, branches of immunity, and conditions of energy availability among humans. Using a prospective mixed-longitudinal design, we collected anthropometric and blood immune biomarker data from 261 Amazonian forager-horticulturalist Shuar children (age 4-11 y old). This strategy provided baseline measures of participant stature, s.c. body fat, and humoral and cell-mediated immune activity as well as subsample longitudinal measures of linear growth (1 wk, 3 mo, 20 mo) and acute inflammation. Multilevel analyses demonstrate consistent negative effects of immune function on growth, with children experiencing up to 49% growth reduction during periods of mildly elevated immune activity. The direct energetic nature of these relationships is indicated by (i) the manifestation of biomarker-specific negative immune effects only when examining growth over timeframes capturing active competition for energetic resources, (ii) the exaggerated impact of particularly costly inflammation on growth, and (iii) the ability of children with greater levels of body fat (i.e., energy reserves) to completely avoid the growth-inhibiting effects of acute inflammation. These findings provide evidence for immunologically and temporally diverse body fat-dependent tradeoffs between immune function and growth during childhood. We discuss the implications of this work for understanding human developmental energetics and the biological mechanisms regulating variation in human ontogeny, life history, and health.

Evaluating minimally invasive sample collection methods for telomere length measurement

OBJECTIVES

Telomere length (TL) is a biomarker of aging and age-related decline. Although venous blood is considered the "gold standard" for TL measurement, its collection is often not feasible or desired in nonclinical settings. Saliva and dried blood spots (DBS) have been used as alternatives when venipuncture cannot be performed. However, it is not known whether these sample types yield TL measurements comparable to those obtained from venous blood. We sought to determine whether different samples from the same individual yield comparable TL measurements.

METHODS

We extracted DNA from matched buffy coat, saliva (Oragene and Oasis), and DBS (venous and capillary) samples from 40 women aged 18-77 years. We used the monochrome multiplex qPCR (MMQPCR) assay to measure TL in all sample types for each participant and applied quality control measures to retain only high-quality samples for analysis. We then compared TL from buffy coat and saliva to examine how these measurements differ and to test if TL is correlated across sample types.

RESULTS

TL differed significantly across buffy coat, Oragene saliva, and Oasis saliva samples. TL from buffy coat and Oragene saliva was moderately correlated (ρ = 0.48, P = .002) and the most similar in size. Oasis saliva TL was not correlated with buffy coat or Oragene saliva TL, and was the shortest. DBS DNA yields were inadequate for TL measurement using the MMQPCR assay.

CONCLUSIONS

Using a matched dataset we demonstrate that sample type significantly influences the TL measurement obtained using the MMQPCR assay.