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.

Variation in diurnal cortisol patterns among the Indigenous Shuar of Amazonian Ecuador.

OBJECTIVES: The hypothalamic-pituitary-adrenal (HPA) axis and its primary end product, the glucocorticoid cortisol, are major components of the evolved human stress response. However, most studies have examined these systems among populations in high-income settings, which differ from the high pathogen and limited resource contexts in which the HPA axis functioned for most of human evolution. METHODS: We investigated variability in diurnal salivary cortisol patterns among 298 Indigenous Shuar from Amazonian Ecuador (147 males, 151 females; age 2-86 years), focusing on the effects of age, biological sex, and body mass index (BMI) in shaping differences in diurnal cortisol production. Saliva samples were collected three times daily (waking, 30 minutes post-waking, evening) for three consecutive days to measure key cortisol parameters: levels at waking, the cortisol awakening response, the diurnal slope, and total daily output. RESULTS: Age was positively associated with waking levels and total daily output, with Shuar juveniles and adolescents displaying significantly lower levels than adults (p < .05). Sex was not a significant predictor of cortisol levels (p > .05), as Shuar males and females displayed similar patterns of diurnal cortisol production across the life course. Moreover, age, sex, and BMI significantly interacted to moderate the rate of diurnal cortisol decline (p = .027). Overall, Shuar demonstrated relatively lower cortisol concentrations than high-income populations. CONCLUSIONS: This study expands the documented range of global variation in HPA axis activity and diurnal cortisol production and provides important insights into the plasticity of human stress physiology across diverse developmental and socioecological settings.

The utility of dried blood spot measurement of bone turnover markers in biological anthropology.

OBJECTIVES: Bone is a dynamic organ under continual turnover influenced by life history stage, energy dynamics, diet, climate, and disease. Bone turnover data have enormous potential in biological anthropology for testing evolutionary and biocultural hypotheses, yet few studies have integrated these biomarkers. In the present article we systematically review the current availability, future viability, and applicability of measuring bone turnover markers (BTMs) in dried blood spot (DBS) samples obtained from finger prick whole blood. METHODS: Our review considers clinical and public health relevance, biomarker stability in DBS, assay availability, and cost. We consider biomarkers of bone formation such as osteocalcin (bone matrix protein), PINP (N-terminal propeptide of type I collagen), and alkaline phosphatase (osteoblast enzyme), as well as biomarkers of bone resorption such as CTX (marker of collagen breakdown) and TRACP5b (tartrate-resistant acid phosphatase 5b; osteoclast enzyme). RESULTS: Two BTMs have been validated for DBS: osteocalcin (formation) and TRACP5b (resorption). Prime candidates for future development are CTX and PINP, the formation and resorption markers used for clinical monitoring of response to osteoporosis treatment. CONCLUSION: BTMs are a field-friendly technique for longitudinal monitoring of skeletal biology during growth, reproduction and aging, combining minimized risk to study participants with maximized ease of sample storage and transport. This combination allows new insights into the effects of energy availability, disease, and physical activity level on bone, and questions about bone gain and loss across life history and in response to environmental factors; these issues are important in human biology, paleoanthropology, bioarchaeology, and forensic anthropology.

Minimally invasive biomarkers in human population biology research, part 2: An introduction to the special issue.

Over the past several decades, biomarkers have become indispensable tools in human biology, allowing researchers to investigate biocultural and evolutionary questions and to generate basic data on health and well-being. Human biologists are central players in biomarker methods development, pioneering the creation of "field friendly," minimally invasively collected biomarker approaches, as well as leading the innovative use of biomarkers, most notably to map the complex pathways from social and environmental conditions to altered physiology to health effects. This special issue, Part 2 of a collection focused on minimally invasively collected biomarkers, is comprised of nine papers that jointly contribute to driving the science of biomarker methods development and application. This compilation of papers engages with topics such as biological normalcy, ecoimmunology, and the ethics of working with vulnerable and underserved populations. It also focuses attention on research areas at present not emphasized in human biology such as bone turnover markers as a window onto osteoporosis and osteoarthritis and the use of cancer-related biomarkers in population screening and epidemiology. Taken together, these papers help draw the roadmap for future biomarker work, emphasizing: (1) the need for systematic and transparent approaches to assay validation, with open access publication; (2) simultaneous measurement of multiple biomarkers and expanded use of instrument platforms that increase the range of physiological, genomics, and omics markers available to researchers; and, (3) increased attention to ethics and researcher responsibilities, encouraging a mindset that recognizes our obligation to provide benefits to individuals and communities and to help redress past abuses.

A comparison of faecal glucocorticoid metabolite concentration and gut microbiota diversity in bonobos (Pan paniscus).

Sex, age, diet, stress and social environment have all been shown to influence the gut microbiota. In several mammals, including humans, increased stress is related to decreasing gut microbial diversity and may differentially impact specific taxa. Recent evidence from gorillas shows faecal glucocorticoid metabolite concentration (FGMC) did not significantly explain gut microbial diversity, but it was significantly associated with the abundance of the family Anaerolineaceae. These patterns have yet to be examined in other primates, like bonobos (Pan paniscus). We compared FGMC to 16S rRNA amplicons for 202 bonobo faecal samples collected across 5 months to evaluate the impact of stress, measured with FGMC, on the gut microbiota. Alpha diversity measures (Chao's and Shannon's indexes) were not significantly related to FGMC. FGMC explained 0.80 % of the variation in beta diversity for Jensen-Shannon and 1.2% for weighted UniFrac but was not significant for unweighted UniFrac. We found that genus SHD-231, a member of the family Anaerolinaceae had a significant positive relationship with FGMC. These results suggest that bonobos are relatively similar to gorillas in alpha diversity and family Anaerolinaceae responses to FGMC, but different from gorillas in beta diversity. Members of the family Anaerolinaceae may be differentially affected by FGMC across great apes. FGMC appears to be context dependent and may be species-specific for alpha and beta diversity but this study provides an example of consistent change in two African apes. Thus, the relationship between physiological stress and the gut microbiome may be difficult to predict, even among closely related species.

Greater chronic morbidity is associated with greater fatigue in six countries: A case of evolutionary mismatch?

Background and objectives: Human susceptibility to chronic non-communicable disease may be explained, in part, by mismatches between our evolved biology and contemporary environmental conditions. Disease-induced fatigue may function to reduce physical activity during acute infection, thereby making more energy available to mount an effective immune response. However, fatigue in the context of chronic disease may be maladaptive because long-term reductions in physical activity increase risks of disease progression and the acquisition of additional morbidities. Here, we test whether cumulative chronic morbidity is associated with subjective fatigue. Methodology: We constructed a cumulative chronic morbidity score using self-reported diagnoses and algorithm-based assessments, and a subjective fatigue score based on four questionnaire items using cross-sectional survey data from the Study on global AGEing and adult health, which features large samples of adults from six countries (China, Ghana, India, Mexico, Russia and South Africa). Results: In a mixed-effects linear model with participants nested in countries (N = 32 455), greater cumulative chronic morbidity is associated with greater subjective fatigue (ß = 0.34, SE = 0.005, P < 2e-16). This association replicates within each country and is robust to adjustment for key sociodemographic and physical covariates (sex, age, household wealth, physical function score, habitual physical activity, BMI and BMI2). Conclusions and implications: Fatigue is a common but perhaps maladaptive neuropsychological response to chronic morbidity. Disease-induced fatigue may mediate a self-perpetuating cycle, in which chronic morbidity reduces physical activity, and less physical activity increases cumulative chronic morbidity. Longitudinal research is needed to test whether chronic morbidity, fatigue and physical activity form a cyclical feedback loop. Lay Summary: Fatigue during acute illness may promote recovery, but persistent fatigue in the context of chronic disease may make matters worse. We present evidence from six countries that more chronic disease is associated with more fatigue. This fatigue may reduce physical activity, which increases risks of acquiring additional chronic health problems.

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.

After Theranos: Using point-of-care testing to advance measures of health biomarkers in human biology research.

OBJECTIVES: The rise and fall of the health technology startup Theranos is emblematic of the promise and peril of point-of-care testing (POCT). Instruments that deliver immediate results from minimally invasive samples at the location of collection can provide powerful tools to deliver health data in clinical and public health contexts. Yet, POCT availability is driven largely by market interests, which limits the development of inexpensive tests for diverse health conditions that can be used in resource-limited settings. These constraints, combined with complex regulatory hurdles and substantial ethical challenges, have contributed to the underutilization of POCT in human biology research. METHODS: We evaluate current POCT capabilities and limitations, discuss promising applications for POCT devices in resource-limited settings, and discuss the future of POCT. RESULTS: As evidenced by publication trends, POCT platforms have rapidly advanced in recent years, gaining traction among clinicians and health researchers. We highlight POCT devices of potential interest to population-based researchers and present specific examples of POCT applications in human biology research. CONCLUSIONS: Several barriers can limit POCT applications, including cost, lack of regulatory approval for non-clinical use, requirements for expensive equipment, and the dearth of validation in remote field conditions. Despite these issues, we see immense potential for emerging POCT technology capable of analyzing new sample types and used in conjunction with increasingly common technology (e.g., smart phones). We argue that the fallout from Theranos may ultimately provide an opportunity to advance POCT, leading to more ethical data collection and novel opportunities in human biology research.

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.

Suicidal ideation in older Ghanaian women: The roles of bodily pain, functional limitation, and chronic health conditions.

BACKGROUND: Although approximately 79% of the world's suicides occur in low- and middle-income countries (LMICs), the limited research in these regions has primarily focused on the rates of suicide attempts (SA) and ideation among men and younger members of the population. AIM: This study investigated the associations between bodily pain, functional limitation, chronic health conditions, and suicidal ideation among older Ghanaian women with a positive screen for depression. METHODS: Data was obtained from the World Health Organization's Study on global AGEing and adult health (SAGE) Ghana Wave 1, a nationally representative sample. Based on the interpersonal theory of suicide, we used logistic regression analysis to investigate the associations between the variables. RESULTS: Functional limitation, bodily pain, hopelessness, and hypertension were significantly associated with a higher risk of suicidal ideation after accounting for sociodemographic and other confounding factors. CONCLUSIONS: Early interventions designed to decrease hopelessness, hypertension, and functional limitations may lead to reduced suicide ideation among older Ghanaian women who screen positive for depression.

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.

Pathogen disgust sensitivity protects against infection in a high pathogen environment.

Disgust is hypothesized to be an evolved emotion that functions to regulate the avoidance of pathogen-related stimuli and behaviors. Individuals with higher pathogen disgust sensitivity (PDS) are predicted to be exposed to and thus infected by fewer pathogens, though no studies have tested this directly. Furthermore, PDS is hypothesized to be locally calibrated to the types of pathogens normally encountered and the fitness-related costs and benefits of infection and avoidance. Market integration (the degree of production for and consumption from market-based economies) influences the relative costs/benefits of pathogen exposure and avoidance through sanitation, hygiene, and lifestyle changes, and is thus predicted to affect PDS. Here, we examine the function of PDS in disease avoidance, its environmental calibration, and its socioecological variation by examining associations among PDS, market-related lifestyle factors, and measures of bacterial, viral, and macroparasitic infection at the individual, household, and community levels. Data were collected among 75 participants (ages 5 to 59 y) from 28 households in three Ecuadorian Shuar communities characterized by subsistence-based lifestyles and high pathogen burden, but experiencing rapid market integration. As predicted, we found strong negative associations between PDS and biomarkers of immune response to viral/bacterial infection, and weaker associations between PDS and measures of macroparasite infection, apparently mediated by market integration-related differences. We provide support for the previously untested hypothesis that PDS is negatively associated with infection, and document variation in PDS indicative of calibration to local socioeconomic conditions. More broadly, findings highlight the importance of evolved psychological mechanisms in human health outcomes.

Childhood Daily Energy Expenditure Does Not Decrease with Market Integration and Is Not Related to Adiposity in Amazonia.

BACKGROUND: Childhood overweight and obesity (OW/OB) is increasingly centered in low- and middle-income countries (LMICs) as rural populations experience market integration and lifeway change. Most explanatory studies have relied on imprecise estimates of children's energy expenditure, restricting understanding of the relative effects of changes in diet and energy expenditure on the development of OW/OB in transitioning contexts. OBJECTIVES: This study used gold-standard measurements of children's energy expenditure to investigate the changes that underlie OW/OB and the nutrition/epidemiologic transition. METHODS: Cross-sectional data were collected from "rural" (n = 43) Shuar forager-horticulturalist children and their "peri-urban" (n = 34) Shuar counterparts (age 4-12 y) in Amazonian Ecuador. Doubly labeled water measurements of total energy expenditure (TEE; kcal/d), respirometry measurements of resting energy expenditure (REE; kcal/d), and measures of diet, physical activity, immune activity, and market integration were analyzed primarily using regression models. RESULTS: Peri-urban children had higher body fat percentage (+8.1%, P < 0.001), greater consumption of market-acquired foods (multiple P < 0.001), lower concentrations of immune activity biomarkers (multiple P < 0.05), and lower REE (-108 kcal/d, P = 0.002) than rural children. Despite these differences, peri-urban children's TEE was indistinguishable from that of rural children (P = 0.499). Moreover, although sample-wide IgG concentrations and household incomes predicted REE (both P < 0.05), no examined household, immune activity, or physical activity measures were related to children's overall TEE (all P > 0.09). Diet and energy expenditure associations with adiposity demonstrate that only reported consumption of market-acquired "protein" and "carbohydrate" foods predicted children's body fat levels (multiple P < 0.05). CONCLUSIONS: Despite underlying patterns in REE, Shuar children's TEE is not reliably related to market integration and-unlike dietary measures-does not predict adiposity. These findings suggest a leading role of changing dietary intake in transitions to OW/OB in LMICs.

Market integration and soil-transmitted helminth infection among the Shuar of Amazonian Ecuador.

BACKGROUND: Soil-transmitted helminth (STH) infections have many negative health outcomes (e.g., diarrhea, nutritional deficiencies) that can also exacerbate poverty. These infections are generally highest among low-income populations, many of which are also undergoing market integration (MI; increased participation in a market-based economy). Yet the direct impact of MI-related social and environmental changes on STH infection patterns is poorly understood, making it unclear which lifestyle factors should be targeted to better control disease spread. This cross-sectional study examines if household infrastructure associated with greater MI is associated with lower STH burdens among Indigenous Ecuadorian Shuar. METHODS: Kato-Katz fecal smears were used to determine STH infection status and intensity (n = 620 participants; 308 females, 312 males, aged 6 months-86 years); Ascaris lumbricoides (ascarid) and Trichuris trichiura (whipworm) were the primary infection types detected. Structured interviews assessing lifestyle patterns (e.g., measures of household infrastructure) measured participant MI. Multilevel regression analyses and zero-inflated negative binomial regression models tested associations between MI measures and STH infection status or intensity, controlling for individual and community characteristics. RESULTS: Participants residing in more market-integrated households exhibited lower infection rates and intensities than those in less market integrated households. Parasite infection status and T. trichiura infection intensity were lower among participants living in houses with wood floors than those with dirt floors, while individuals using well or piped water from a spring exhibited lower A. lumbricoides infection intensities compared to those using river or stream water. Unexpectedly, latrine type was not significantly related to STH infection status or intensity. These results suggest that sources of exposure differ between the two helminth species. CONCLUSIONS: This study documents associations between household measures and STH infection among an Indigenous population undergoing rapid MI. These findings can help healthcare programs better target interventions and reduce STH exposure among at-risk populations.

Development and validation of an ELISA for a biomarker of thyroid dysfunction, thyroid peroxidase autoantibodies (TPO-Ab), in dried blood spots.

BACKGROUND: The prevalence of allergic and autoimmune conditions has been steadily increasing in wealthy nations over the past century. One hypothesis put forward to explain this is the Old Friends Hypothesis, which posits that increased hygiene, urbanization, and lifestyle changes have reduced our exposure to parasites and microbes that we co-evolved with, resulting in immune dysregulation. However, research in traditionally living populations, who are exposed to greater parasite and pathogen loads such as those encountered during our evolution, is limited, in part due to a lack of minimally invasive, field-friendly biomarkers of autoimmune disorders. We therefore developed an ELISA to assess positivity for thyroid peroxidase autoantibody (TPO-Ab), an indicator of autoimmune thyroid disease, based on dried blood spot (DBS) samples. RESULTS: We used the Accubind anti-thyroid peroxidase test system to screen our validation samples comprising matched fingerprick DBS, venous DBS, and plasma samples from 182 adults. After confirming that we had TPO-Ab-positive individuals in our validation sample (n = 12), we developed an indirect ELISA to measure TPO-Ab levels from one 3-mm DBS punch. The sensitivity and specificity of our assay for DBS samples ranged from 91.7-100% and 98.2-98.8%, respectively, using a cut-off value of ≥ 26 IU/mL. Intra-assay reliability for duplicate quality control DBS punches was 5.2%, while inter-assay reliability ranged from 11.5-24.4% for high, medium, and low DBS controls. Dilutional linearity ranged from 80 to 120%, and spike and recovery experiments indicated that the DBS matrix does not interfere with the detection of TPO-Ab. TPO-Ab levels remained stable in DBS samples stored at - 28 °C or - 80 °C, but decreased over time in DBS samples kept at 22 °C or at 37 °C. CONCLUSIONS: We developed an in-house, kit-independent indirect ELISA assay to determine individuals' TPO-Ab positivity based on dried blood spots, representing a cost-effective method with potential applications in a range of research settings.

Inflammation and central adiposity as mediators of depression and uncontrolled diabetes in the study on global AGEing and adult health (SAGE).

OBJECTIVES: Diabetes and depression are commonly present in the same individuals, suggesting the possibility of underlying shared physiological processes. Inflammation, as assessed with the biomarker C-reactive protein (CRP), has not consistently explained the observed relationship between diabetes and depression, although both are associated with inflammation and share proposed inflammatory mechanisms. Central adiposity has also been associated with both conditions, potentially by causing increased inflammation. This study uses the World Health Organization's Study on global AGEing and adult health (SAGE) Mexico Wave 1 biomarker data (n = 1831) to evaluate if inflammation and central adiposity mediate the relationship between depression and diabetes. METHODS: Depression was estimated using a behavior-based diagnostic algorithm, inflammation using venous dried blood spot (DBS) CRP, central adiposity using waist-to-height ratio (WHtR), and uncontrolled diabetes using venous DBS-glycated hemoglobin (HbA1c). RESULTS: The association between depression and uncontrolled diabetes was partially mediated by CRP before but not after WHtR was considered. When WHtR was added to the model, it partially mediated the relationship between diabetes and depression while fully mediating the relationship between depression and CRP. CONCLUSIONS: These findings suggest that central adiposity may be a more significant mediator between diabetes and depression than inflammation and account for the relationship between these disorders and inflammation. Depression may cause an increase in central adiposity, which then may lead to diabetes, but the increase in known systemic inflammatory pathways caused by central adiposity may not be the key pathological mechanism.

Validation of an enzyme-linked immunoassay assay for osteocalcin, a marker of bone formation, in dried blood spots.

OBJECTIVES: Investigating factors that contribute to bone loss and accretion across populations in remote settings is challenging, particularly where diagnostic tools are scarce. To mitigate this challenge, we describe validation of a commercial ELISA assay to measure osteocalcin, a biomarker of bone formation, from dried blood spots (DBS). METHODS: We validated the Osteocalcin Human SimpleStep ELISA kit from Abcam (ab1951214) using 158 matched plasma and DBS samples. Passing-Bablok regression analysis assessed the relationships between plasma and DBS osteocalcin concentrations. Dilutional linearity and spike and recovery experiments determined if the DBS matrix interfered with osteocalcin measurement, and intra- and inter-assay coefficients of variation (CVs) were calculated. Limit of detection, analyte stability, and specific forms of osteocalcin measured by the kit were also investigated. RESULTS: Mean plasma osteocalcin value was 218.2 ng/mL (range 64.6-618.1 ng/mL). Linear relationships existed between plasma and DBS concentrations of osteocalcin, with no apparent bias in plasma vs DBS concentrations. There was no apparent interference of the DBS matrix with measurement of osteocalcin in DBS. Intra-assay CV for DBS was ~8%, while average inter-assay CV was 14.8%. Limit of detection was 0.34 ng/mL. Osteocalcin concentrations were stable in DBS stored at -28°C and room temperature, but not those stored at 37°C. This ELISA kit detects total osteocalcin. CONCLUSIONS: Osteocalcin, a bone formation biomarker, can be measured from DBS. Combined with a previously validated DBS assay for TRACP-5b, a bone resorption biomarker, these assays have the potential to help researchers disentangle the many factors contributing to bone strength.

The developmental origins of risk and time preferences across diverse societies.

Risk and time preferences have often been viewed as reflecting inherent traits such as impatience and self-control. Here, we offer an alternative perspective, arguing that they are flexible and environmentally informed. In Study 1, we investigated risk and time preferences among children in the United States, India, and Argentina, as well as forager-horticulturalist Shuar children in Amazonian Ecuador. We find striking cross-cultural differences in behavior: children in India, the United States, and Argentina are more risk-seeking and future-oriented, whereas Shuar children are more risk-averse and exhibit more heterogeneous time preferences, on average preferring more today choices. To explore 1 of the socioecological forces that may be shaping these preferences, in Study 2, we compared the behavior of more and less market-integrated Shuar children, finding that those in market-integrated regions are more future-oriented and risk-seeking. These findings indicate that cross-cultural differences in risk and time preferences can be traced into childhood and may be influenced by the local environment. More broadly, our results contribute to a growing understanding of plasticity and variation in the development of behavior. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

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.

Knee osteoarthritis risk in non-industrial societies undergoing an energy balance transition: evidence from the indigenous Tarahumara of Mexico.

Non-industrial societies with low energy balance levels are expected to be less vulnerable than industrial societies to diseases associated with obesity including knee osteoarthritis. However, as non-industrial societies undergo rapid lifestyle changes that promote positive energy balance, individuals whose metabolisms are adapted to energetic scarcity are encountering greater energy abundance, increasing their propensity to accumulate abdominal adipose tissue and thus potentially their sensitivity to obesity-related diseases. OBJECTIVES: Here, we propose that knee osteoarthritis is one such disease for which susceptibility is amplified by this energy balance transition. METHODS: Support for our hypothesis comes from comparisons of knee radiographs, knee pain and anthropometry among men aged ≥40 years in two populations: Tarahumara subsistence farmers in Mexico undergoing the energy balance transition and urban Americans from Framingham, Massachusetts. RESULTS: We show that despite having markedly lower obesity levels than the Americans, the Tarahumara appear predisposed to accrue greater abdominal adiposity (ie, larger abdomens) for a given body weight, and are more vulnerable to radiographic and symptomatic knee osteoarthritis at lower levels of body mass index. Also, proportionate increases in abdomen size in the two groups are associated with greater increases in radiographic knee osteoarthritis risk among the Tarahumara than the Americans, implying that the abdominal adipose tissue of the Tarahumara is a more potent stimulus for knee degeneration. CONCLUSIONS: Heightened vulnerability to knee osteoarthritis among non-industrial societies experiencing rapid lifestyle changes is a concern that warrants further investigation since such groups represent a large but understudied fraction of the global population.