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Objectives: Maternal socioeconomic status (SES) is an important predictor of adverse birth outcomes and postnatal health across global populations. Chronic inflammation is implicated in cardiometabolic disease risk in high‐income contexts and is a potential pathway linking maternal adversity to offspring health trajectories. To clarify how socioeconomic inequality shapes pregnancy inflammation in middle‐income settings, we investigated SES as a predictor of inflammatory cytokines in late gestation in a sample from the Cebu Longitudinal Health Nutrition Survey in Cebu, Philippines. Methods: We used multiple regression to evaluate maternal SES, reflected in household assets, as a predictor of general inflammation (C‐reactive protein), inflammatory cytokines (interleukin‐6, interleukin‐10), and inflammatory balance (n = 407). Inflammatory markers were measured at 29.9 weeks gestation in dried blood spots, and a measure reflecting relative balance of IL6 and IL10 was calculated to capture pro‐ versus anti‐inflammatory skewed immune profiles. Results: Greater household assets significantly predicted lower IL6 concentration (p < 0.001), with a trend toward lower IL6 relative to IL10 (p = 0.084). C‐reactive protein and IL10 were not individually related to SES. Conclusions: The inverse relationship between SES and pregnancy inflammation in Cebu is consistent with results from high‐income settings. These findings further highlight the influence of socioeconomic conditions on immune regulation during pregnancy. Given the evidence that gestational inflammation impacts offspring fetal growth, our results suggest that social and economic effects on immune function may be an important pathway for the intergenerational transmission of health disparities. [ABSTRACT FROM AUTHOR]

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Dysregulated inflammation underlies many human diseases, and measures of responsiveness to activation, and sensitivity to inhibition, provide important information beyond baseline assessments of chronic inflammation. This study implements a simplified cell culture protocol in a school‐based setting, using finger stick capillary blood collected from 333 adolescents (age 11.4–15.6 years) incubated with lipopolysaccharide (LPS). Median cytokine responses for IL6, IL1β, and TNFα were 61.9, 26.2, and 11.2 pg/mL, respectively. Samples were also incubated with LPS and glucocorticoid (GC) to measure GC sensitivity. Median responses were reduced in the presence of GC inhibition for IL6 (20.3 pg/mL), IL1β (10.5 pg/mL), and TNFα (3.3 pg/mL). Minimally invasive cell culture protocols provide novel opportunities for measuring inflammatory phenotypes in a wide range of non‐clinical settings. [ABSTRACT FROM AUTHOR]

Objectives: Recent discussions in human biology have highlighted how local ecological contexts shape the relationship between social stressors and health across populations. Chronic low‐grade inflammation has been proposed as a pathway linking social stressors to health, with evidence concentrated in high‐income Western contexts. However, it remains unclear whether this is an important pathway in populations where prevalence is lower due to lower adiposity and greater infectious exposures. To investigate this further, we tested associations between multiple types of intimate partner violence (IPV), a highly prevalent stressor and health crisis globally, and C‐reactive protein (CRP), a commonly used measure of chronic low‐grade inflammation, in Cebu, Philippines. For reference, we compared results for CRP to depression, a well‐established and consistently observed health outcome of IPV. Methods: Data came from 1601 currently partnered women (ages 35–69 years) as part of the Cebu Longitudinal Health and Nutrition Survey. IPV exposures included physical, emotional, and controlling behavior. Depression scores were measured using a modified version of the Center for Epidemiologic Studies‐Depression Scale for this population, whereas plasma CRP was measured from overnight‐fasted morning blood samples. Results: All three types of IPV were associated with a higher depression score. However, none of the IPV measures were associated with CRP. In a post hoc interaction test, emotional IPV became positively associated with CRP as waist circumference increased above the mean. Conclusions: Our results suggest a complex relationship between social stressors and chronic low‐grade inflammation, which is likely dependent on the population‐specific context of lifestyle and environmental factors. [ABSTRACT FROM AUTHOR]

Objectives: The drivers of human life expectancy gains over the past 200 years are not well‐established, with a potential role for historical reductions in infectious disease. We investigate whether infectious exposures in infancy predict biological aging using DNA methylation‐based markers that forecast patterns of morbidity and mortality later in life. Methods: N = 1450 participants from the Cebu Longitudinal Health and Nutrition Survey—a prospective birth cohort initiated in 1983—provided complete data for the analyses. Mean chronological age was 20.9 years when venous whole blood samples were drawn for DNA extraction and methylation analysis, with subsequent calculation of three epigenetic age markers: Horvath, GrimAge, and DunedinPACE. Unadjusted and adjusted least squares regression models were evaluated to test the hypothesis that infectious exposures in infancy are associated with epigenetic age. Results: Birth in the dry season, a proxy measure for increased infectious exposure in the first year of life, as well as the number of symptomatic infections in the first year of infancy, predicted lower epigenetic age. Infectious exposures were associated with the distribution of white blood cells in adulthood, which were also associated with measures of epigenetic age. Conclusions: We document negative associations between measures of infectious exposure in infancy and DNA methylation‐based measures of aging. Additional research, across a wider range of epidemiological settings, is needed to clarify the role of infectious disease in shaping immunophenotypes and trajectories of biological aging and human life expectancy. [ABSTRACT FROM AUTHOR]

Objectives: The gut microbiome (GM) connects physical and social environments to infant health. Since the infant GM affects immune system development, there is interest in understanding how infants acquire microbes from mothers and other household members. Materials and Methods: As a part of the Cebu Longitudinal Health and Nutrition Survey (CLHNS), we paired fecal samples (proxy for the GM) collected from infants living in Metro Cebu, Philippines at 2 weeks (N = 39) and 6 months (N = 36) with maternal interviews about prenatal household composition. We hypothesized that relationships between prenatal household size and composition and infant GM bacterial diversity (as measured in fecal samples) would vary by infant age, as well as by household member age and sex. We also hypothesized that infant GM bacterial abundances would differ by prenatal household size and composition. Results: Data from 16 S rRNA bacterial gene sequencing show that prenatal household size was the most precise estimator of infant GM bacterial diversity, and that the direction of the association between this variable and infant GM bacterial diversity changed between the two time points. The abundances of bacterial families in the infant GM varied by prenatal household variables. Conclusions: Results highlight the contributions of various household sources to the bacterial diversity of the infant GM, and suggest that prenatal household size is a useful measure for estimating infant GM bacterial diversity in this cohort. Future research should measure the effect of specific sources of household bacterial exposures, including social interactions with caregivers, on the infant GM. [ABSTRACT FROM AUTHOR]

Objective: A growing body of evidence suggests inflammatory markers can help predict poor outcomes in pregnancy. We evaluated C‐reactive protein (CRP)—a key biomarker of inflammation—before and after a safe immune provocation (the seasonal influenza vaccine) during pregnancy. We evaluated predictors of the magnitude of response, as well as the association between CRP response and birth outcomes. Methods: Nonrandomized prospective cohort trial measuring CRP before and 3 days after administering seasonal flu vaccine to low‐risk obstetrical patients in Calgary, Alberta. Results: We analyzed 27 prevaccination/postvaccination samples. Body mass index (BMI) was positively associated with CRP at Day 0, and women with higher prepregnancy BMI had a less robust response to vaccination than did leaner women. There was a strong positive association between CRP response and infant birth weight; women who had the greatest response to vaccination (by tertile) gave birth to babies that weighed, on average, 256.2 g more than babies born to women with the lowest response. Conclusions: Higher BMI in pregnant women was associated with higher baseline CRP and less pronounced CRP response to vaccination. Stronger CRP response was associated with higher birth weight. These findings underscore the potential value of a more dynamic approach to studying the regulation of inflammation during pregnancy and its implications for birth outcomes. This study was registered as a clinical trial in clinicaltrials.gov (ID: REB15/1418). [ABSTRACT FROM AUTHOR]

Objectives: Inflammatory cytokines are key regulators of inflammation, but current measurement approaches require venous blood to quantify low circulating concentrations associated with chronic, low‐grade inflammation. This article describes a highly sensitive multiplex immunoassay protocol for the measurement of IL6, IL8, IL10, and TNFα in finger stick dried blood spot (DBS) samples. Methods: The protocol uses a multiplex electrochemiluminescent immunoassay platform. The following measures of assay performance were evaluated: reliability (inter‐assay percent coefficient of variation; %CV), precision (intra‐assay %CV), lower limit of detection (LLD), linearity of dilution, and agreement with results from matched plasma samples. Results: Analysis of three control samples across the assay range indicated an acceptable level of precision and reliability for each cytokine. Linearity of dilution returned average values that ranged from 104.1 to 127.6% of expected. Lower limits of detection for IL6, IL8, and IL10 were <0.5, and <1.0 pg/ml for TNFα. Level of agreement in results between matched DBS and plasma samples was high for all cytokines except for IL8. Conclusions: Finger stick DBS sampling provides a viable alternative to venipuncture for the quantification of IL6, IL10, and TNFα at low concentrations associated with chronic inflammation. The presence of red blood cells may interfere with the quantification of IL8 in DBS. In facilitating blood collection in nonclinical settings this method can advance scientific understandings of how social and ecological contexts shape immune function and health over the life course. [ABSTRACT FROM AUTHOR]

Exposome and low birthweight selection bias considerations in early life infections and epigenetic age relationships. Reply to Nwanaji-Enwerema, 2023, "Exposome and low birthweight selection bias considerations in early life infections and epigenetic age relationships" While birth weight was not the focus of our analysis, we have previously reported in detail associations between birth weight - and other measures of nutrition during pregnancy - and measures of epigenetic age (Kuzawa et al., [3]). [Extracted from the article]

Objectives: Socioeconomic status (SES) is a powerful determinant of health, but the underlying biological mechanisms are poorly understood. This study investigates whether levels of DNA methylation at CpG sites across the genome are associated with SES in a cohort of young adults in the Philippines. Methods: DNA methylation was assayed with the Illumina HumanMethylation450 Bead Chip, in leukocytes from 489 participants in the Cebu Longitudinal Health and Nutrition Survey (mean age = 20.9 years). SES was measured in infancy/childhood and adulthood, and was based on composite measures of income, assets, and education. Genome‐wide analysis of variable probes identified CpG sites significantly associated with SES after adjustment for multiple comparisons. Functional enrichment analysis was used to identify biological pathways associated with these sites. Results: A total of 2,546 CpG sites, across 1,537 annotated genes, were differentially methylated in association with SES. In comparison with high SES, low SES was associated with increased methylation at 1,777 sites, and decreased methylation at 769 sites. Functional enrichment analysis identified over‐representation of biological pathways related to immune function, skeletal development, and development of the nervous system. Conclusions: Socioeconomic status predicts DNA methylation at a large number of CpG sites across the genome. The scope of these associations is commensurate with the wide range of biological systems and health outcomes that are shaped by SES, and these findings suggest that DNA methylation may play an important role. [ABSTRACT FROM AUTHOR]

Objective: Cross‐culturally, men's T declines in response to pairbonding and fatherhood, but less is known about what happens to T during and after life history transitions that theoretically lead to renewed mating effort. We tested whether men's T rises (or declines less with age) as their children age, or when pairbonds end, independent of changes in fatherhood‐related variables such as co‐residence with children. Methods: We used demographic, behavioral, and salivary hormone data (waking and pre‐bed T) collected in 2009 and 2014 for the Cebu Longitudinal Health and Nutrition Survey (n = 571 men). Results: Fathers with older children tended to have attenuated decline in pre‐bedtime T between 2009 and 2014 compared to men with younger children, after controlling for pairbonding (ß = 1.58, SE = 0.88, P = 0.074). Separated men had higher pre‐bedtime T than pairbonded men, controlling for fatherhood‐related variables (ß = 11.74, SE = 4.33, P = 0.007). Change in T did not significantly differ for men who separated between the two surveys, relative to men who remained pairbonded throughout. Conclusion: We found modest support for the prediction that men experience less of an age‐related drop in T as their youngest child ages, a trend that might strengthen as children age further. We also replicate the finding that separated men have higher T, although longitudinal changes in the hormone were not significantly different in these men. Our data suggest that, of two life history transitions that may predict renewed mating effort, pair bond loss is more strongly endocrine mediated than potential mating effort shifts related to the aging of children. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: The purpose of this study was to examine anti‐Müllerian hormone (AMH) levels among women of Maya and non‐Maya ancestry in the city of Campeche, Mexico. Levels of AMH can potentially predict age at menopause. Previous studies have indicated an early mean age at menopause among the Maya. Materials and methods: Women aged 40‐60 (n = 97) participated in semistructured interviews, anthropometric measures, and blood samples. Maya/non‐Maya ethnicity was determined by the last names, languages spoken, and birthplace of the woman, her parents, and her grandparents. AMH values were categorized as detectable (0.05‐4.19 ng/mL) and undetectable (<0.05 ng/mL). Logistic regressions calculated odds ratios (OR) for undetectable AMH. Results: Women were categorized as Maya (n = 44), not Maya (n = 39), or not able to be clearly defined (n = 14). In bivariate comparisons, women with detectable levels of AMH were younger, more likely to be pre‐menopausal, and not Maya. Age, menopausal status, and ethnicity remained significant in a logistic regression models after controlling for age at menarche. Maya women were more than five times as likely to have nondetectable AMH levels as non‐Maya women. Discussion: Increasing age and progression through the menopausal transition were both associated with declining levels of AMH. The association between Maya ethnicity and a lower likelihood of detecting AMH is consistent with the early ages at menopause reported in previous studies. We considered a rapid life history model as an explanatory framework, and suggest, from an ecological perspective, that future research should consider measures of developmental stress that may compromise ovarian reserves. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To validate a method for measuring endotoxin‐core antibodies (EndoCAb) from dried blood spots (DBS)—drops of capillary whole blood collected and dried on filter paper—as an indicator of environmental enteropathy (EE) in infancy and early childhood. Methods: A commercially available enzyme immunoassay kit was adapted for use with DBS, with optimized steps for sample elution. Technical validation included analysis of linearity/recovery, precision and reliability, lower limit of detection, and correspondence between matched plasma and DBS samples. Validation in a field‐based setting was implemented with samples from Peruvian infants (n = 82; age = 2–33 months) collected at two time points six months apart. Results: A high correspondence between plasma and DBS levels of EndoCAb was observed (R2 = 0.93, P < .001). The lower limit of detection was found to be 0.01 GMU/mL. Interassay coefficient of variation (CV) was 10.9% and 8.06% for low and high controls, respectively. Mean intra‐assay CVs were 3.22% and 1.83%, respectively. In a sample of Peruvian infants, EndoCAb levels increased with age as expected (P < .001). Age explained nearly 34.6% of the variance in EndoCAb across the sample. Conclusion: These findings demonstrate the validity and feasibility of measuring EndoCAb in remote field settings using minimally invasive DBS sampling. [ABSTRACT FROM AUTHOR]

Objectives A low second-to-fourth (2D:4D) digit ratio, a retrospective marker of high prenatal androgens, predicts increased investment in costly sexually dimorphic traits in men in some studies, although results are mixed. Here we test the hypothesis that the association of low 2D:4D ratios with increased muscularity and decreased adiposity depends on current testosterone (T) levels, such that digit ratio will be a particularly strong predictor of outcomes among men exhibiting a mating-effort-oriented endocrinological profile (high T). We also test the association between 2D:4D and somatic traits independently of T. Materials and methods We related 2D:4D digit ratios, and their interaction with T, to handgrip strength, lean mass, arm muscle area, and skinfold thickness in a sample of young, childess men (20-22 y) from Cebu, Philippines ( N = 623). Results Digit ratio did not significantly predict men's T-dependent somatic traits. Interactions between 2D:4D and morning T, similarly, did not predict male muscularity or adiposity. Although two of the interactions were significant or marginally significant ( p < .1), after adjusting for multiple testing the evidence in support of our hypothesis was weak. Discussion We found no evidence that 2D:4D predicted measures of somatic reproductive effort in this sample of young men from Cebu, who as a group could be considered mostly mating-oriented. These relationships were also not contingent upon, or stronger, when considering the moderating effect of concurrent T levels. In this sample, 2D:4D was therefore either a poor proxy of prenatal androgen exposure or prenatal androgens had limited influence on adult somatic outcomes. [ABSTRACT FROM AUTHOR]

Objectives The androgen receptor (AR) mediates expression of androgen-associated somatic traits such as muscle mass and strength. Within the human AR is a highly variable glutamine short-tandem repeat (AR-CAGn), and CAG repeat number has been inversely correlated to AR transcriptional activity in vitro. However, evidence for an attenuating effect of long AR-CAGn on androgen-associated somatic traits has been inconsistent in human populations. One possible explanation for this lack of consistency is that the effect of AR-CAGn on AR bioactivity in target tissues likely varies in relation to circulating androgen levels. Materials and Methods We tested whether relationships between AR-CAGn and several androgen-associated somatic traits (waist circumference, lean mass, arm muscle area, and grip strength) were modified by salivary (waking and pre-bed) and circulating (total) testosterone (T) levels in young adult males living in metropolitan Cebu, Philippines ( n = 675). Results When men's waking T was low, they had a reduction in three out of four androgen-associated somatic traits with lengthening AR-CAGn ( p < .1), consistent with in vitro research. However, when waking T was high, we observed the opposite effect-lengthening AR-CAGn was associated with an increase in these same somatic traits. Discussion Our finding that longer AR-CAGn predicts greater androgen-associated trait expression among high-T men runs counter to in vitro work, but is generally consistent with the few prior studies to evaluate similar interactions in human populations. Collectively, these results raise questions about the applicability of findings derived from in vitro AR-CAGn studies to the receptor's role in maintaining androgen-associated somatic traits in human populations. [ABSTRACT FROM AUTHOR]

Objectives Testosterone (T), the primary androgenic hormone in males, is stimulated through pulsatile secretion of LH and regulated through negative feedback inhibition at the hypothalamus and pituitary. The hypothalamic-pituitary-gonadal (HPG) axis also controls sperm production through the secretion of follicle-stimulating hormone (FSH). Negative feedback in the HPG axis is achieved in part through the binding of T to the androgen receptor (AR), which contains a highly variable trinucleotide repeat polymorphism (AR-CAGn). The number of repeats in the AR-CAGn inversely correlates with transcriptional activity of the AR. Thus, we predicted longer AR-CAGn to be associated with higher T, LH, and FSH levels. Methods We examined the relationship between AR-CAGn and total plasma T, LH, and FSH, as well as 'bioavailable' morning (AM-T) and evening (PM-T) testosterone in 722 young (21.5 ± 0.5 years) Filipino males. Results There was no relationship between AR-CAGn and total T, AM-T, or LH ( P > .25 for all). We did observe a marginally non-significant ( P = .066) correlation between AR-CAGn and PM-T in the predicted direction, and a negative correlation between AR-CAGn and FSH ( P = .005). Conclusions Our results both support and differ from previous findings in this area, and study parameters that differ between our study and others, such as participant age, sample time, and the role of other hormones should be considered when interpreting our findings. While our data point to a modest effect of AR-CAGn on HPG regulation at best, the AR-CAGn may still affect somatic traits by regulating androgenic activity at peripheral tissues. [ABSTRACT FROM AUTHOR]

Problem Maternal inflammation undergoes adaptations during pregnancy, and excessive inflammation has been associated with adverse outcomes. One mechanism may be maternal inflammation transmission to the fetal compartment. Links between maternal pregnancy inflammation and fetal inflammation are poorly characterized. Method Principal components analysis was used to extract underlying inflammation components across cytokines ( IFN-γ, IL-10, IL-13, IL-6, IL-8, TNF-α) in two pregnancy cohorts ( SPAH N=87, MOMS N=539) assessed during the second and third trimesters. Links between maternal inflammation over pregnancy and fetal (cord blood) inflammation were assessed. Results Substantial cytokine rank-order stability was observed in both cohorts, β's range .47-.96 , P's <.001. Two consistent inflammatory components were extracted: a pro-inflammatory ( IL-10, IL-6, IL-8, TNF-α, IFN-γ) component and anti-inflammatory ( IL-13) component. Higher maternal pro-inflammatory and lower anti-inflammatory indices during pregnancy were associated with higher cord blood inflammation, P's>.04. Conclusion Maternal inflammation indices over pregnancy were associated with inflammation in cord blood at birth. Results have implications for understanding pregnancy inflammatory processes and how maternal inflammation may be transmitted to fetal circulation. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Cross-species comparisons show that high extrinsic mortality favors the evolution of 'faster' life histories. There is interest in applying this principle to human life history plasticity, based on the idea that psychosocial stressors that correlate with extrinsic mortality accelerate reproductive pace. Most prior studies have been conducted in settings in which psychosocial stressors co-occur with the maturation-accelerating influence of nutritional abundance. Materials and Methods We evaluate cues of local mortality (sibling death) or low parental investment (paternal instability; maternal absence) and energetic measures during development as predictors of life history scheduling among males ( n = 754) in a Philippine population with marginal developmental nutritional. Results Males who had more favorable nutritional status during childhood, as reflected in linear growth, skinfold thickness, and caloric intake, were more maturationally advanced in adolescence (all P < 0.05). Taller stature and higher caloric intake during childhood also predicted earlier ages at first sex (both P < 0.01), which persisted after controlling for the effect of nutrition on pubertal maturation. While psychosocial stressors did not predict accelerated maturation, males who as children grew up with an unstable paternal presence had sex earlier ( P < 0.05) and tended to become fathers sooner than those with a stable fatherly presence. Those who had a sibling die became fathers sooner than those who did not ( P < 0.05). Discussion Our findings point to important energetic constraints on the onset of reproductive maturity, while psychosocial stressors accelerate entry to parenthood, which may be comparatively more socially, rather than biologically, constrained. Am J Phys Anthropol 158:175-184, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Proponents of global market expansion claim that economic growth brings prosperity and creates a more equitable global society, yet these efforts may result in the exacerbation of economic disparities that translates into significant disparities in health. These trends underscore the importance of research examining the social determinants of health in an increasingly unequal world. This article brings together concepts from biocultural anthropology, developmental origins of health and disease, and research examining the long-term effects of early environments on social capital to formulate the notion of biosocial inheritance. Biosocial inheritance is the process whereby social adversity in one generation is transmitted to the next through reinforcing biological and social mechanisms that impair health, exacerbating social and health disparities. Such a theoretical framework considers contemporary and historic political-economic forces that shape inequalities in human health, across generations. We examine the biosocial determinants of growth in the Andes as a case study of biosocial inheritance, developing a model that will illuminate the contemporary and historic sources of persistent poverty in low-income communities around the world. By highlighting the biosocial mechanisms underpinning the intergenerational transmission of poverty, this model allows for the formulation of interventions aimed at breaking the cycle of poverty and a reconsideration of the way we think about poverty and social mobility. [ABSTRACT FROM AUTHOR]

Objectives We used detailed saliva sampling procedures to test for diurnal changes in men's salivary estradiol (E2) and testosterone (T) and assessed whether greater adiposity predicted higher E2 and T. Methods We drew on a subsample of young adults enrolled in a long-running birth cohort study in Metro Cebu, Philippines. Subjects provided saliva samples at four time points during the day (waking, waking +40 min, early evening, and bedtime), which were assayed for E2 and T. Using these detailed hormonal data, we calculated E2 ( n = 29) and T ( n = 44) area-under-the-curve values, which provide insights on hormonal production over the study period. Results While T declined immediately after waking and reached a nadir in the early evening, E2 did not show significant diurnal change ( P ≥ 0.1) but was positively correlated to T at multiple time points ( P ≤ 0.05). Subjects with higher adiposity (BMI, waist circumference, skinfolds) had elevated E2 secretion throughout the day ( P ≤ 0.01), but adiposity was not related to salivary T. Conclusions Consistent with past research, our results indicate that adipose tissue is a significant site of E2 production in males but differ from a limited number of prior studies of young men in that we did not find lower T with increasing adiposity. Given E2's role in male hypothalamic-pituitary-gonadal function and complex interfaces with the immune system, these results have important implications for models of male life history as rates of overweight and obesity rise in populations around the world. Am. J. Hum. Biol. 26:376-383, 2014. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT Dried blood spots (DBS)-drops of capillary whole blood collected from finger stick-represent a minimally invasive alternative to venipuncture that facilitates the collection of blood samples from research participants in naturalistic, field-based research settings. But the number of validated assays for quantifying biomarkers in DBS samples is relatively low in comparison with serum or plasma. The objective of this review is to discuss the advantages and disadvantages of DBS sampling, and to outline the steps involved in developing and validating an immunoassay for application to DBS samples. These steps include deciding on reagents, preparing calibration and quality control material, evaluating elution protocols, optimizing sample quantity, and assessing multiple aspects of assay performance, including intra- and interassay variation, lower limit of detection, accuracy, stability, and agreement between results from matched DBS and plasma samples. The broader goal of this 'how-to' approach is to encourage investigators to validate, implement, and disseminate assay protocols for DBS samples in order to advance field-based research on human biology. Am. J. Hum. Biol. 26:1-9, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives We assessed the responsiveness of salivary progesterone (P4) and estradiol (E2) to father-child interaction, including testing for differences in short-term hormonal change based on paternal characteristics. We also predicted that P4 exposure during the study period would relate positively to post-interaction paternal mood. Methods We conducted an in-home intervention study in which fathers ( n = 44) played with their toddlers. Subjects provided saliva samples before interacting with their children, with additional collections 40 and 70 min later. Results E2 did not significantly change over the study period ( P > 0.4). P4 declined significantly from baseline to 40 min ( P < 0.05) and 70 min ( P < 0.001). Men reporting that the interaction made them feel very happy/relaxed had greater P4 exposure from baseline through 70 min (area under the curve) compared with men reporting less positive post-interaction mood ( P < 0.05). This relationship persisted after controlling for cortisol. Men's % decrease in P4 (baseline to 40 min) was significantly greater if they had an infant ( P < 0.05), while fathers' % decline in E2 (baseline to 70 min) was larger if they had more children ( P < 0.05). Conclusions These results require replication but could indicate that grouping fathers with different levels of experience obscures meaningful variation in hormonal responses to child interaction. Our findings appear consistent with the effects of P4 as a mood enhancer and suggest future research should explore the possible role of P4 as hormonal mechanism that could reinforce or facilitate paternal investment. Am. J. Hum. Biol. 25:491-498, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives: Pregnancy and lactation involve adaptations in immune regulation, but little is known about cross-cultural variation in inflammatory changes during pregnancy or lactation. Here we report concentrations of C-reactive protein (CRP) in a large cross-sectional sample of healthy Filipino women who vary in parity, gestational, and lactational status, and who come from a population previously described as having low CRP. Methods: Fasting plasma CRP was measured among female participants (ages 20.8-22.4 years) in the Cebu Longitudinal Health and Nutrition Survey ( n = 822). Results: Median CRP was 0.2 mg/l in nulliparous women and peaked at 2.0 mg/l in women in their 3rd trimester of pregnancy. Parous but post-partum women had higher CRP compared to nulliparous women, which was largely explained by body composition differences as reflected in waist circumference and skinfold measures. Among post-partum women with infants, CRP was similar in women who were currently breastfeeding compared to those who were not. Conclusions: At Cebu, women late in gestation have 10-fold higher C-reactive protein compared to nulliparous women, with no evidence that lactation is inflammatory. These population-based findings are similar with findings from prior clinic-based studies and are consistent with the maternal immunological adaptations initiated during pregnancy. The tendency of human females to spend more time than females of other great apes in gestation rather than lactation suggests that the human life history strategy involved increased time spent by reproductively aged females in a pro-inflammatory state. Am. J. Hum. Biol., 2013. © 2012Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives: Despite ample evidence of variation in timing of menopause, little is known about the extent or underlying causes of individual variation in ovarian reserve and age-related follicular decline. Anti-Müllerian hormone (AMH), a hormonal marker of ovarian reserve, may be a useful tool to clarify these questions. We describe AMH in a cohort of Filipino young adult women, and evaluate whether ovarian reserve in early adulthood relates to measures of life history scheduling (menarcheal age) and reproductive effort (parity). Methods: Data and samples are obtained from 294 nonpregnant participants (21.5 years ± 0.3) in the Cebu Longitudinal Health and Nutrition Survey. Plasma AMH was assayed using an enzyme immunoassay and relationships between AMH, menarcheal age, and parity were examined. Results: Mean AMH was 4.3 ng/mL. In multiple regression models, women who experienced menarche earlier had significantly higher AMH as young adults ( P < 0.05). Women with two ( P < 0.05) and three or more ( P < 0.01) children had significantly lower AMH than those with no children. These associations were independent of age, smoking, and body mass index. Conclusions: These findings suggest that individual variation in life history scheduling and reproductive history could contribute to variation in ovarian reserve. Moreover, they demonstrate the utility of AMH as a tool for human reproductive ecology, and highlight the need for further research clarifying the extent of human population variation in ovarian reserve and the behavioral and ecological influences underlying this variation. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objective: Although psychosocial stress has also been implicated as a contributor to growth failure by imposing energetic constraints during development, the direct physiological pathways by which these life history trade-offs are imposed are not well understood. This study explores associations between diurnal cortisol rhythms and differential patterns of linear child growth among the Tsimane, a horticulturalist and foraging society in the Bolivian Amazon. Methods: Waking and bedtime salivary cortisol samples ( n = 243) were collected from 53 Tsimane' children ages 1.6-6 over 3 days as part of a larger study of developmental trajectories in hypothalamic-pituitary-adrenal axis dynamics. Anthropometric measurements and survey data were collected in conjunction with the Tsimane' Amazonian panel study (TAPS). Results: Among children under the age of 6, diurnal rhythms in stunted versus nonstunted children vary dramatically: stunted children display elevated cortisol at both the AM ( P = 0.03) and PM ( P = 0.02) collection points. Multilevel regression analysis demonstrates an inverse relationship between cortisol and height-for-age z-score status ( P = 0.00), which is mediated, in part, by infection ( P = 0.00), and is strongest among male children (n.s.). Moreover, the poorest statural growth is exhibited among children with high cortisol living in more acculturated Tsimane' communities, a proxy for a more adverse developmental milieu. Conclusions: This study reports a small, but significant, life history cost of elevated diurnal cortisol rhythms on linear growth among Tsimane' children, and provides critical insight into the developmental origins of health differentials among an indigenous Amazonian population experiencing rapid lifestyle changes. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives: C-reactive protein (CRP) is a central component of innate immune defenses, and high sensitivity CRP has emerged as an important biomarker of chronic inflammation and cardiovascular disease risk. Prior analyses of CRP variability have reported stable between-individual differences in CRP over time, but a limitation of current knowledge is that it is based on research conducted in post-epidemiologic transition populations. Methods: This study evaluated CRP variability among adults in the southeastern region of the Ecuadorian Amazon where rates of infectious diseases remain high. Blood samples were collected from 52 adults at four weekly sampling intervals and were quantified using a high-sensitivity immunoassay. Results: Median CRP concentration was 0.52 mg/l. About 34.6% of participants had CRP >3 mg/l at one time point, but no individuals had CRP >3 mg/l across two or more sampling intervals, and within-individual correlations revealed low levels of stable, between-individual differences in CRP. The application of current guidelines for the assessment of chronic inflammation failed to detect a single case of 'high risk' CRP. Conclusions: This study is the first to investigate CRP variability in a nonindustrialized, high infectious disease environment. It documents a pattern of variation over time that is distinct from prior research, with no evidence for chronic low-grade inflammation. These results may have substantial implications for research on inflammation and diseases of aging globally, as well as for scientific understandings of the regulation of inflammation. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Although humans are considered unusual among mammals for the intensity of care that fathers often provide offspring, little is known about the hormonal architecture regulating human paternal investment. Prolactin has important reproductive functions in both female and male mammals and other taxa, making it a candidate regulator of human paternal behavior. Notably, prolactin is higher during periods of offspring care in some species, but it is unknown if this pattern occurs in human fathers. We draw on a sample of men ( n = 289; age 21-23 at baseline) from Metropolitan Cebu City, Philippines to evaluate relationships between prolactin, assayed from dried blood spots, and components of reproductive behavior and relationship status. In this sample, fathers had higher prolactin than nonfathers ( P = 0.006), and fathers of infants had borderline higher prolactin than fathers of older children ( P = 0.054). Among single nonfathers at baseline (2005), baseline prolactin did not predict who transitioned to fatherhood by follow-up 4.5 years later. Among nonfathers, men with greater prolactin reported more lifetime sexual partners ( P = 0.050) as well as more sexual activity in the month before sampling ( P = 0.060). Our results suggest that fathers in Cebu have higher prolactin than nonfathers, with hormone levels highest among fathers of young infants. Although these findings are generally consistent with evidence from other species for pronurturing effects of prolactin, evidence for positive relationships between the hormone and measures of sexual behavior at Cebu point to likely complexities in the hormone's involvement in male reproductive strategy. Am J Phys Anthropol 148:362-370, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Objectives: Infancy represents a window of development during which long-term immunological functioning can be influenced. In this study, we evaluate proxies of microbial exposures in infancy as predictors of interleukin-4 (IL-4) in young adulthood. IL-4 is an immunoregulatory cytokine that plays a role in the pathogenesis of atopic and allergic diseases. Methods: Data were obtained from 1,403 participants in the Cebu Longitudinal Health and Nutrition Survey, an ongoing population-based study in the Philippines. Relationships between microbial and nutritional environments in infancy and plasma IL-4 concentrations in adulthood were evaluated using tobit regression models. Results: Having older siblings and more episodes of respiratory illness in infancy significantly predicted lower concentrations of plasma IL-4 in adulthood. Unexpectedly, more episodes of diarrheal illness in infancy were associated with higher IL-4 in adulthood. Interactions between a composite household pathogen exposure score and the duration of exclusive breastfeeding approached significance. This interaction showed that the negative association between household pathogen exposure in infancy and adult IL-4 was only significant for individuals who had been exclusively breastfed for a short duration of time. Finally, currently living in an urban household was unexpectedly, negatively associated with adult IL-4. Associations were independent of early nutrition, socioeconomic status (SES), and urbanicity, as well as current measures of infection, body fat, SES, and smoking. Conclusions: This study builds on a growing body of literature demonstrating that early ecological conditions have long-term effects on human biology by providing evidence that multiple proxies of microbial exposures in infancy are associated with adult IL-4. Am. J. Hum. Biol. 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Inflammation is a central part of innate immunity, but its role in anti-pathogen defenses has been overshadowed by recent interest in the contribution of inflammation to a wide range of chronic degenerative diseases. Current research on chronic inflammation is conducted primarily in affluent populations with low levels of infectious disease; comparative research in different ecological settings is needed to advance understandings of the causes and consequences of variation in the regulation of inflammation. This article investigates the levels and predictors of interleukin-6 (IL-6) and interleukin-10 (IL-10)-two cytokines important to the regulation of inflammation-in a large, population-based study in the Philippines. Concentrations of IL-6 and IL-10 were determined in N = 1,569 healthy young adults (20-22 years) in Metro Cebu, Philippines. IL-6 and IL-10 concentrations were positively correlated, and body mass index and symptoms of infectious disease were both associated with higher concentrations of IL-6 and IL-10. Median concentrations of IL-6 (1.0 pg/mL) and IL-10 (7.56 pg/mL) were substantially lower and higher, respectively, than levels reported for other populations based on a systematic review of prior research. This study contributes to a growing body of research in human ecological immunology, and suggests that there may be substantial population differences in the regulation of inflammation that has implications for the association between inflammation and disease. Am J Phys Anthropol, 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Objectives: Although cortisol (CORT) may suppress testosterone (T) production under stress, in many species males' T and CORT are co-elevated during mate acquisition or conspecific competition. It is presently unknown how CORT co-varies with T in relation to fatherhood/relationship status in men. Here we evaluate associations between waking (AM) and pre-bed (PM) salivary CORT and T, and with plasma total T and luteinizing hormone. We also test whether co-elevationor co-downregulation of CORT and T are present in men who are mating-oriented (non-pairbonded, non-fathers) and parenting-oriented (pairbonded and/or fathers), respectively. Methods: Data come from 630 of young adult Filipino males (21-23 years) enrolled in the Cebu Longitudinal Health and Nutrition Survey, a population-based birth cohort study in Cebu City, Philippines. Results: T and CORT were positively related in AM ( r = 0.37) and PM ( r = 0.30) saliva samples (both P < 0.001). The positive relationship between AM measures was strengthened as caloric intake improved (interaction P < 0.05). Mating-oriented men were more likely to have co-elevated PM CORT and T ( P < 0.05), defined as being in the highest tertile for both hormones, while parenting-oriented men were more likely to have co-downregulated (lowest tertile for both hormones) AM ( P < 0.05) and PM ( P < 0.001) CORT and T. Conclusions: CORT and T are positively related upon waking and before bed and are more likely to be co-elevated in mating-oriented men and co-downregulated in parenting-oriented men. Our findings support the interpretation that CORT and T serve complementary roles in facilitating men's mating effort. Am. J. Hum. Biol. 2011. © 2011 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Inflammation has been associated with a wide range of chronic degenerative diseases, but the developmental factors contributing to the regulation of inflammation are poorly understood. This study investigates the within-individual association between antibody response to vaccination in adolescence and C-reactive protein (CRP) concentration in young adulthood. In 1998-99, at age 14-15 years, a subset of participants ( N = 96) in the Cebu Longitudinal Health and Nutrition Survey were administered a typhoid vaccine, and baseline and follow-up blood samples were drawn to assess the strength of the antibody response to vaccination. In 2005, at age 20-21 years, blood samples were drawn from the full cohort for measurement of CRP. N = 74 individuals had complete data at both time points. Bivariate associations and multivariate logistic regression models were evaluated to test the hypothesis that vaccine responsiveness in adolescence was significantly associated with CRP level in young adulthood. There was a strong and statistically significant association between antibody response to vaccination in adolescence and CRP in young adulthood. Median CRP was more than four times higher among nonresponders than responders, and nonresponders were 2.3 to 3.6 times more likely to have CRP in the top tertile of the sample distribution. This study provides evidence for a prospective, within-individual link between more effective antibody-mediated immune defenses and lower levels of inflammation. In the context of prior research in this population, these results suggest that early environments are important determinants of multiple aspects of an individual's immuno-phenotype. Am. J. Hum. Biol., 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Growing evidence suggests that economic inequality in a community harms the health of a person. Using panel data from a small-scale, preindustrial rural society, we test whether individual wealth rank and village wealth inequality affects self-reported poor health in a foraging-farming native Amazonian society. A person's wealth rank was negatively but weakly associated with self-reported morbidity. Each step up/year in the village wealth hierarchy reduced total self-reported days ill by 0.4 percent. The Gini coefficient of village wealth inequality bore a positive association with self-reported poor health that was large in size, but not statistically significant. We found small village wealth inequality, and evidence that individual economic rank did not change. The modest effects may have to do with having used subjective rather than objective measures of health, having small village wealth inequality, and with the possibly true modest effect of a person's wealth rank on health in a small-scale, kin-based society. Finally, we also found that an increase in mean individual wealth by village was related to worse self-reported health. As the Tsimane' integrate into the market economy, their possibilities of wealth accumulation rise, which may affect their well-being. Our work contributes to recent efforts in biocultural anthropology to link the study of social inequalities, human biology, and human-environment interactions. [ABSTRACT FROM AUTHOR]

Researchers have hypothesized that the degree to which an individual's actual behavior approximates the culturally valued lifestyle encoded in the dominant cultural model has consequences for physical and mental health. We contribute to this line of research by analyzing data from a longitudinal study composed of five annual surveys (2002-2006 inclusive) from 791 adults in one society of foragers-farmers in the Bolivian Amazon, the Tsimane'. We estimate the association between a standard measure of individual achievement of the cultural model, cultural consonance, and three indicators of body morphology. Drawing on research suggesting that in societies in the early stages of economic development an increase in socioeconomic status is associated with an increase in mean body mass, we expect to find a positive association between cultural consonance and three anthropometric measures. We found the expected positive association between cultural consonance and anthropometric measures--especially for men--only when using ordinary least square (OLS) regression models, but not when using fixed-effects regression models. The real magnitude of the association was low. The comparison of estimates from OLS and fixed-effect regression models suggests that previous findings on the effects of cultural consonance on body morphology using cross-sectional data should be read with caution because the association might be largely explained by fixed characteristics of individuals not accounted in OLS models. [ABSTRACT FROM AUTHOR]

The article presents a study on the effect of breastfeeding on childhood obesity in the U.S. The study evaluated the relation between body mass index (BMI) and infant feeding using linear-, logistic-, and sibling fixed-effects regression models. Results show that breast feeding during infancy may help against obesity and these results could provide additional support for implementation of policies made to support breastfeeding mothers, according to the authors.

The article presents a study on the risk factors for elevated C-reactive protein (CRP) among women in the Philippines to characterize the changes in waist circumference over 11-year interval. The study evaluates the current circumference and changes using regression analysis to predict the presence of elevated plasma CRP concentration. Results suggest the association of current waist circumference with a higher risk of elevated CRP, however, history of adiposity may be reversible by weight loss.

The article focuses on the study on statural growth of 146 girls and 158 boys in 13 Tsimane villages in Beni, Bolivia through annual observation from 2002 to 2006. The study provides separate descriptive and visual analysis of growth in height of boys and girls and estimates the growth gained by stunted children using panel linear multiple regression. It shows that children had catch-up growth rates of 0.11 standard deviation (SD) per year and growth rates do not differ on child's sex.

The article discusses the result of a study which evaluated iron deficiency as a nutritional adaptation to infectious disease. The research examines the association between infection, iron status and zinc protoporphyrin to heme ratio and concluded that iron deficiency may protection children against acute infection.

ABSTRACT The purpose of this study was to investigate the impact of economic and cultural change on immune function and psychosocial stress in an indigenous Siberian population. We examined Epstein-Barr virus antibodies (EBV), an indirect biomarker of cell-mediated immune function, in venous whole blood samples collected from 143 Yakut (Sakha) herders (45 men and 98 women) in six communities using a cross-sectional study design. We modeled economic change through the analysis of lifestyle incongruity (LI), calculated as the disparity between socioeconomic status and material lifestyle, computed with two orthogonal scales: market and subsistence lifestyle. EBV antibody level was significantly negatively associated with both a market and a subsistence lifestyle, indicating higher cell-mediated immune function associated with higher material lifestyle scores. In contrast, LI was significantly positively associated with EBV antibodies indicating lower immune function, and suggesting higher psychosocial stress, among individuals with economic status in excess of material lifestyle. Individuals with lower incongruity scores (i.e., economic status at parity with material resources, or with material resources in excess of economic status) had significantly lower EBV antibodies. The findings suggest significant health impacts of changes in material well-being and shifting status and prestige markers on health during the transition to a market economy in Siberia. The findings also suggest that relative, as opposed to absolute, level of economic status or material wealth is more strongly related to stress in the Siberian context. [ABSTRACT FROM AUTHOR]

The article focuses on the study that evaluates the social aspirations, everyday stressors, psychological distress and mental health problems in an urban elite of young Afghans in Kabul, Afghanistan. The study focuses on the factors affecting the widespread frustrations, hinging on restricted opportunities for social advancement, education and employment. Results that show the psychological stress, considering the context of persistent insecurity and widening economic inequality are included.

The article presents a study on leptin and body fat among children and adolescents of lowland Bolivia. Results showed that in males, leptin is weakly correlated with most measures of body composition at all ages examined. In females, however, the level of body fat and the strength of the correlation between body fat and leptin both increases notably with age. It suggests that leptin functions as a signal of energy stores among females as they approach reproductive maturity.

The article reports on the results of a study of the effect of rainfall during gestation and early childhood on adult height in a foraging and horticultural society of the Bolivian Amazon. A description of the experimental set-up and measurement method is presented. The study showed that rainfall amount and variability during gestation and birth year bore weak associations with adult height.

Rapid globalization is forcing youth around the world to confront new developmental challenges, and conceptual models are needed that can capture this experience and its developmental implications. Exposure to nontraditional lifestyles opens up new socialization opportunities and raises the possibility of stress-inducing dissonance between participating socializing agents and the messages they deliver. Socialization ambiguity is introduced as a model for culture change and adolescent stress, and it is applied to a sample of 10- to 20-year-olds ( N=295) in the islands of Samoa. A physiological marker of stress (antibodies against the Epstein-Barr virus) is employed to overcome some of the difficulties associated with measuring stress outcomes. Socialization ambiguity is found to be a significant source of stress on the remote island of Savai'i and the transitional area of rural Upolu, although the direction of the association is different, possibly reflecting divergent socialization goals in these two regions. [ABSTRACT FROM AUTHOR]

Within anthropology and human biology, there is growing interest in immune function and its importance to the ecology of human health and development. Biomedical research currently dominates our understanding of immunology, and this paper seeks to highlight the potential contribution of a population-based, ecological approach to the study of human immune function. Concepts from life-history theory are applied to highlight the major challenges and demands that are likely to shape immune function in a range of ecological contexts. Immune function is a major component of maintenance effort, and since resources are limited, trade-offs are expected between investment in maintenance and other critical life-history functions involving growth and reproduction. An adaptationist, life-history perspective helps make sense of the unusual developmental trajectory of immune tissues, and emphasizes that this complex system is designed to incorporate information from the surrounding ecology to guide its development. As a result, there is substantial population variation in immune development and function that is not considered by current biomedical approaches. In an attempt to construct a framework for understanding this variation, immune development is considered in relation to the competing life-history demands that define gestation, infancy, childhood, adolescence, and adulthood. Each life stage poses a unique set of adaptive challenges, and a series of hypotheses is proposed regarding their implications for immune development and function. Research in human ecological immunology is in its earliest stages, but this is a promising area of exploration, and one in which anthropology is well-positioned to make important contributions. Yrbk Phys Anthropol 46:100-125, 2003. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Methods Results Conclusions This study tests the hypothesis that self‐reported somatic symptoms are associated with biomarkers of stress, including elevated blood pressure and suppressed immune function, among Shuar adults living in the Ecuadorian Amazon.Research was conducted in three Shuar communities in the Upano Valley of the Ecuadorian Amazon and included the collection of biomarkers and a structured morbidity interview. Participants self‐reported somatic symptoms such as headaches, body pain, fatigue, and other bodily symptoms. We examined whether the number of somatic symptoms reported was associated with measures of immune (Epstein–Barr virus [EBV] antibodies) and cardiovascular (blood pressure) functioning in 97 Shuar adults (37 women, 60 men; ages 18–65 years). Multivariate linear regression analyses were used to examine the relationships among somatic symptoms and stress biomarkers, controlling for age, sex, body mass index (BMI), active infection, level of education, and income.Controlling for relevant covariates, Shuar adults reporting the highest level of somatic symptoms (three symptoms) were more likely to exhibit elevated systolic (β = 0.20, p = 0.04) and diastolic blood pressure (β = 0.23, p = 0.03), in comparison to adults reporting no symptoms. Shuar adults reporting two symptoms, compared to no symptoms, were more likely to exhibit elevated EBV antibody concentrations (β = 0.34, p = < 0.01).These preliminary findings demonstrate that somatic symptoms reported by Shuar men and women are associated with physiological measures widely associated with chronic psychosocial stress. These findings complement the cross‐cultural literature in medical anthropology documenting the close connection between the expression of somatic symptoms and stressful life circumstances and highlight the important role that human biologists can play in exploring biocultural phenomena. [ABSTRACT FROM AUTHOR]

Objective: Interleukin-6 (IL-6) is a pro-inflammatory cytokine that is associated with the production of C-reactive protein, the acute phase response, and chronic low-grade inflammation. In this report, we describe and validate a highly sensitive enzyme-linked immunosorbent assay (ELISA) for quantifying IL-6 at low concentrations in samples of capillary whole blood collected from a simple finger stick and dried on filter paper (dried blood spots, DBS). Methods: A commercially available ELISA for IL-6 was modified to develop a protocol for the quantification of IL-6 in DBS samples. Procedures for sample elution and incubation were optimized for precision, reliability, accuracy, and lower limit of detection using small volumes of DBS. A set of 46 matched serum/DBS samples were used to evaluate agreement between serum and DBS results. Results: The protocol demonstrated acceptable levels of precision, reliability, accuracy, and agreement with serum-based results. The lower limit of detection was sufficiently low to measure levels of IL-6 associated with both chronic, low-grade inflammation, and acute increases in inflammatory activity. Conclusions: This protocol adds to the growing panel of analytes validated for quantification in DBS samples and should facilitate future research on the causes and consequences of inflammation in diverse non-clinical settings. Am. J. Hum. Biol., 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]