Clippers are superior to scissors in the collection of hair for chemical analysis in companion dogs: a Dog Aging Project preliminary study.

OBJECTIVE: To identify the safest, most efficient method for hair sample collection from companion dogs among clippers, scissors, and razors and to validate obtained samples with cortisol concentration analysis. ANIMALS: 25 healthy, privately owned dogs. METHODS: 2 hair samples were collected from each dog's ischiatic region with different implements (scissors, razors, or clippers). The collecting clinician completed a Hair Collection Questionnaire (HCQ) for each sample that compared subjective sample quality, time of collection, restraint needed, and patient experience. Each sample was evaluated by cortisol enzyme immunoassay. RESULTS: Clippers had higher overall HCQ scores than scissors, and scissors had higher HCQ scores than razors. Collection was faster for clippers than scissors, and scissors were faster than razors. There were no differences in sample quality between scissors and clippers, and sample quality was lower with razors. There was no difference in restraint needed or patient experience. Collection of long hair had higher HCQ scores than collection of medium and short hair. Collection of hair from dogs with an undercoat had higher HCQ scores than collection of hair from dogs without an undercoat. Dog size had no effect on HCQ score. Hair cortisol concentration did not vary between scissors or clippers (P = .111). Hair color and age did not affect hair cortisol concentration (P = .966 and P = .676, respectively). CLINICAL RELEVANCE: Clippers are recommended for hair sample collection from companion dogs. Scissors are an adequate alternative.

Hemoglobin measurement in venous blood compared with pooled and single-drop capillary blood: a method-comparison study in a controlled and survey setting in Uganda among children and women.

BACKGROUND: Standard practice for estimating anemia in population-based surveys is to use a point-of-care device to measure hemoglobin (Hb) in a single drop of capillary blood. Emerging evidence points to larger than expected differences in Hb concentration depending on the blood source. OBJECTIVE: We evaluated use of different blood sources to measure Hb with a HemoCue 201+ analyzer compared with the reference method of venous blood tested with a Sysmex XN-450 hematology analyzer. METHODS: Hb concentration in venous, pooled capillary, and single-drop capillary blood were collected in controlled (laboratory) and survey (Demographic Health Survey-8 pilot) settings in Uganda among children 6-59 mo and nonpregnant women 15-49 y. Venous and capillary blood collected from the same individual was tested using a HemoCue 201+ analyzer and the venous blood was also measured with a Sysmex XN-450 hematology analyzer. Agreement between measures was estimated using Lin's concordance correlation coefficient, Bland-Altman plots, and Deming regression. Means and prevalences were compared using paired t-tests and McNemar's tests, respectively. RESULTS: The limits of agreement between Hb measured using a HemoCue 201+ analyzer and the reference method were lowest for venous (1.1-1.96 g/dL), followed by pooled capillary (1.45-2.27 g/dL), and single-drop capillary blood (2.23-3.41 g/dL). Mean differences were <0.5 g/dL across comparators. There were statistically significant differences in Hb concentration from both types of capillary blood. Anemia prevalence was lower in pooled capillary blood compared with the reference method. CONCLUSIONS: The variability of Hb measured by capillary blood using the HemoCue 201+ analyzer is higher than venous blood but the extent to which this impacts the validity of Hb and anemia estimates requires further exploration. Future research is also needed to evaluate the implications of using venous compared with capillary blood in population-based surveys. This trial was registered at clinicaltrials.gov (NCT05059457).

Associations between childhood maltreatment and physiological dysregulation in adulthood: Methodological decisions and implications.

BACKGROUND: Childhood maltreatment is linked with health problems in adulthood. Theoretical models suggest that maltreatment leads to dysregulation in several bodily systems, and this has been corroborated using measures of physiological function (i.e., biomarkers). Methodological decisions involving the measurement of maltreatment and dimension reduction with respect to biomarkers (i.e., combining information across multiple measures) may influence research findings. OBJECTIVE: The present study compares associations between childhood maltreatment and adult physiological dysregulation using multiple dimension reduction approaches and measures of maltreatment. PARTICIPANTS AND SETTING: Participants were recruited, as children, to a prospective study of the correlates and consequences of childhood maltreatment. 253 participants were retained and provided biomarker data at midlife. Physiological dysregulation was operationalized with a conventional allostatic load approach and a novel statistical distance approach. METHODS: Regression models were employed with allostatic load or statistical distance as the outcome and prospectively or retrospectively measured child maltreatment as the primary predictor. RESULTS: When using allostatic load as the outcome, prospectively measured childhood maltreatment was positively associated with physiological dysregulation (b = 0.70, SE = 0.31, p = 0.02). When using statistical distance as the outcome, retrospectively measured childhood maltreatment was positively associated with physiological dysregulation (b = 0.69, SE = 0.19 p < 0.001). CONCLUSIONS: We report a positive association between childhood maltreatment and physiological dysregulation at midlife. However, the significance and magnitude of effects varied with different maltreatment and physiological dysregulation measures. Further review of the methods used to study adult health conditions and their relation to childhood maltreatment is needed.

Mineral Nutrition of Samburu Adolescents: A Comparative Study of Pastoralist Communities in Kenya.

Objectives: This study aimed to characterize mineral nutrition (copper, magnesium, selenium, and zinc) in Samburu pastoralist youth, in the context of differential cultural transitions due to uneven changes in educational access, herding intensity, polygyny, and access to wild, domesticated, and market-sourced foods. Materials and Methods: Whole dried blood spots were collected in a total of 161 youth (highlands, n = 97; lowlands, n = 64) to assess concentrations of: cadmium, copper, lead, magnesium, mercury, selenium, and zinc. Concentrations were determined through Inductively Coupled Mass Spectrometry. Dietary intakes were assessed by 24-hour recall method and calculation of probability of inadequate intakes. WHO protocols were applied to collect anthropometric measures in the youth. Results: Nearly half of the adolescents (47.8%) fell below the reference range for zinc status, and 88.2% had low zinc-to-copper ratios. High probability of nutrient inadequacies were evident for protein, fat, vitamins A, B12, C, and E. In generalized linear modeling, lowland residence was negatively associated with zinc status and the zinc-to-copper ratio, and positively correlated with selenium and copper status. Other significant correlates were: dairy livestock ownership; wife number of the youth's mother; meat consumption; vegetable consumption; protein intake; infectious disease morbidities; BMI; and hemoglobin concentrations. Discussion: In recent decades, Samburu pastoralists of northern Kenya have experienced marked dietary changes in the context of market integration, extreme drought, diminishing pasture availability, and violent civil conflict. Some children (particularly boys) successfully supplement their diets by foraging for wild foods, while others (particularly actively herding girls) may be more vulnerable.

Multiplexed micronutrient, inflammation, and malarial antigenemia assessment using a plasma fractionation device.

Processing and storing blood samples for future analysis of biomarkers can be challenging in resource limited environments. The preparation of dried blood spots (DBS) from finger-stick collection of whole blood is a widely used and established method as DBS are biosafe, and allow simpler field processing, storage, and transport protocols than serum or plasma. Therefore, DBS are commonly used in population surveys to assess infectious disease and/or micronutrient status. Recently, we reported that DBS can be used with the Q-plex™ Human Micronutrient 7-plex Array (MN 7-plex), a multiplexed immunoassay. This tool can simultaneously quantify seven protein biomarkers related to micronutrient deficiencies (iodine, iron and vitamin A), inflammation, and malarial antigenemia using plasma or serum. Serum ferritin, an iron biomarker, cannot be measured from DBS due to red blood cell (RBC) ferritin content confounding the results. In this study, we assess a simple blood fractionation tool that passively separates plasma from other blood components via diffusion through a membrane into a plasma collection disc (PCD). We evaluated the concordance of MN 7-plex analyte concentrations from matched panels of eighty-eight samples of PCD, DBS, and wet plasma prepared from anticoagulated venous whole blood. The results showed good correlations of >0.93 between the eluates from PCD and DBS for each analyte except ferritin; while correlations seen for plasma/PCD were weaker. However, the recovery rate of the analytes from the PCD were better than those from DBS. The serum ferritin measures from the PCD were highly correlated to wet plasma samples (0.85). This suggests that surveillance for iron status in low resource settings can be improved over the current methods restricted to only measuring sTfR in DBS. When used in combination with the MN 7-plex, all seven biomarkers can be simultaneously measured using eluates from the PCDs.

SARS-CoV-2 specific antibody trajectories in mothers and infants over two months following maternal infection.

Infants exposed to caregivers infected with SARS-CoV-2 may have heightened infection risks relative to older children due to their more intensive care and feeding needs. However, there has been limited research on COVID-19 outcomes in exposed infants beyond the neonatal period. Between June 2020 - March 2021, we conducted interviews and collected capillary dried blood spots from 46 SARS-CoV-2 infected mothers and their infants (aged 1-36 months) for up to two months following maternal infection onset (COVID+ group, 87% breastfeeding). Comparative data were also collected from 26 breastfeeding mothers with no known SARS-CoV-2 infection or exposures (breastfeeding control group), and 11 mothers who tested SARS-CoV-2 negative after experiencing symptoms or close contact exposure (COVID- group, 73% breastfeeding). Dried blood spots were assayed for anti-SARS-CoV-2 S-RBD IgG and IgA positivity and anti-SARS-CoV-2 S1 + S2 IgG concentrations. Within the COVID+ group, the mean probability of seropositivity among infant samples was lower than that of corresponding maternal samples (0.54 and 0.87, respectively, for IgG; 0.33 and 0.85, respectively, for IgA), with likelihood of infant infection positively associated with the number of maternal symptoms and other household infections reported. COVID+ mothers reported a lower incidence of COVID-19 symptoms among their infants as compared to themselves and other household adults, and infants had similar PCR positivity rates as other household children. No samples returned by COVID- mothers or their infants tested antibody positive. Among the breastfeeding control group, 44% of mothers but none of their infants tested antibody positive in at least one sample. Results support previous research demonstrating minimal risks to infants following maternal COVID-19 infection, including for breastfeeding infants.

Heavy metal blood concentrations in association with sociocultural characteristics, anthropometry and anemia among Kenyan adolescents.

OBJECTIVES: To measure heavy metal concentrations among Kenyan youth and quantify associations with sociocultural, demographic, and health factors as well as anthropometry. METHODS: Using data from a study of semi-nomadic pastoralists in Samburu County, Kenya, we measured blood concentrations of lead (Pb), mercury (Hg), and cadmium (Cd) in 161 adolescents. We identified sociocultural, demographic and health characteristics associated with each metal and quantified the association between metals and adolescent anthropometry. RESULTS: Median blood concentrations of Pb, Cd, and Hg were 1.82 µg/dL, 0.24 µg/L and 0.16 µg/L, respectively. Place of residence (highlands vs lowlands) was a determinant of metal concentrations. Hg was inversely related to anemia, and metals were not associated with anthropometry. CONCLUSIONS: In this population of Samburu adolescents, median Pb and Cd blood concentrations were higher than other North American or European biomonitoring studies. These findings motivate further investigation into the environmental sources of metals in this community.

A multicenter analytical performance evaluation of a multiplexed immunoarray for the simultaneous measurement of biomarkers of micronutrient deficiency, inflammation and malarial antigenemia.

A lack of comparative data across laboratories is often a barrier to the uptake and adoption of new technologies. Furthermore, data generated by different immunoassay methods may be incomparable due to a lack of harmonization. In this multicenter study, we describe validation experiments conducted in a single lab and cross-lab comparisons of assay results to assess the performance characteristics of the Q-plex™ 7-plex Human Micronutrient Array (7-plex), an immunoassay that simultaneously quantifies seven biomarkers associated with micronutrient (MN) deficiencies, inflammation and malarial antigenemia using plasma or serum; alpha-1-acid glycoprotein, C-reactive protein, ferritin, histidine-rich protein 2, retinol binding protein 4, soluble transferrin receptor, and thyroglobulin. Validations included repeated testing (n = 20 separately prepared experiments on 10 assay plates) in a single lab to assess precision and linearity. Seven independent laboratories tested 76 identical heparin plasma samples collected from a cohort of pregnant women in Niger using the same 7-plex assay to assess differences in results across laboratories. In the analytical validation experiments, intra- and inter-assay coefficients of variation were acceptable at <6% and <15% respectively and assay linearity was 96% to 99% with the exception of ferritin, which had marginal performance in some tests. Cross-laboratory comparisons showed generally good agreement between laboratories in all analyte results for the panel of 76 plasma specimens, with Lin's concordance correlation coefficient values averaging ≥0.8 for all analytes. Excluding plates that would fail routine quality control (QC) standards, the inter-assay variation was acceptable for all analytes except sTfR, which had an average inter-assay coefficient of variation of ≥20%. This initial cross-laboratory study demonstrates that the 7-plex test protocol can be implemented by users with some experience in immunoassay methods, but familiarity with the multiplexed protocol was not essential.

Design and measurement in a study of war exposure, health, and aging: protocol for the Vietnam health and aging study.

BACKGROUND: Survivors of war throughout the world experience illnesses and injuries that are crucial to understand, given the ongoing treatment and adaptation they demand. In developing countries like Vietnam, where population aging and chronic disease burdens are rapidly rising, aging populations have seen a disproportionate share of armed conflict and related casualties. This paper describes the Vietnam Health and Aging Study (VHAS), a unique resource for investigating mechanisms of association between diverse exposures to armed conflict during the Vietnam War and multiple dimensions of older adult health among survivors of that war. METHODS: The VHAS utilizes a longitudinal design, the first wave of data collection conducted in 2018 among 2447 older adults. A second wave of follow-up data collection, scheduled to take place in 2021, will examine life course, social relational and health and mortality transitions. The VHAS was conducted in four northern Vietnamese districts purposively selected to represent a spectrum of war exposure as indicated by intensity of bombings. Additionally, VHAS uses random sampling within gender and military service subdomains to permit unique gender-specific analyses of military service, trauma exposure and health. The VHAS' face-to-face interviews include modules detailing war and military service experiences; warzone stressors; and multiple dimensions of health such as chronic disease, functional limitation, disability, health behaviors, cognition and psychological health. Biomarker data collected for the full VHAS sample includes anthropometric and functional tests such as grip strength and blood pressure, hair samples for cortisol assay, and capillary blood samples to assay C-reactive protein, cholesterol, HbA1c, and other markers of interest for cardiovascular and other disease risks and for testing the impact of early life stressors on later life health. Blood samples will also permit epigenetic analysis of biological aging. DISCUSSION: Future VHAS investigations will examine dynamic linkages between war exposure, mortality and morbidity, while taking into account the selective nature of each of these processes. Longitudinal analyses will examine late-life health transitions and war-related resiliency.

Development and validation of hair specimen collection methods among extremely short-length Afro-textured hair.

OBJECTIVES: Cortisol, a biomarker of stress, is slowly deposited into the growing hair strands on the head. Meyer, Novak, Hamel, and Rosenberg (2014) established a method for hair cortisol extraction and analysis, and showed that hair cortisol can serve as an integrated measure of psychophysiological stress activity during the period of hormone incorporation into the hair. The hair sample collection methods offered, however, (ie, cutting as close to the scalp as possible with scissors) is inefficient when collecting samples among participants with Afro-textured and extremely short-length hair types. In this article, we propose an alternative method for collecting hair among this group. METHODS: Our proposed alternative method involves sampling hair from all sections of the scalp, rather than the posterior-vertex position alone. This provides more volume of hair making it feasible to extract and analyze cortisol in extremely short-length Afro-textured hair types. To validate this method, we compared a homogeneous specimen of hair cortisol sampled from all regions to that from the posterior-vertex region of the scalp, a region most commonly sampled. RESULTS: There was no statistical difference between the homogeneous mixture and the posterior-vertex region of the scalp. CONCLUSIONS: Our findings suggest that our proposed method may serve as a feasible alternative to the currently prevailing standard collection methodology, and underscores the importance of diversifying hair cortisol research beyond the limitations of developing collection methodologies only suited for straighter-textured hair types.

Measurement of micronutrient deficiency associated biomarkers in dried blood spots using a multiplexed immunoarray.

Simplifying blood collection is often critical when collecting specimens in remote and/or austere settings. The use of dried blood spots (DBS) offers a practical collection method suitable for a wide variety of analytes. A small volume of whole blood can be obtained rapidly through a minimally invasive heel- or finger-stick using a disposable safety lancet. Once dried, the samples require no further processing, are stable for months or longer, pose minimal risk of disease transmission, and are easy to ship. DBS are often used in demographic health surveys to assess infectious disease status in vulnerable populations. These samples can be used to screen biomarkers of micronutrient deficiency (MND) and inflammation. We recently described a multiplexed immunoarray, the Q-plex human micronutrient array, which can simultaneously quantify seven biomarkers related to MND, inflammation and malarial antigenemia using plasma (alpha-1-acid glycoprotein, C-reactive protein, ferritin, histidine-rich protein 2, retinol binding protein, soluble transferrin receptor, and thyroglobulin). In this work, we present a protocol for preparing eluates from DBS samples and their measurement using a modified protocol for this new tool. We evaluated the concordance of analyte concentrations (excluding ferritin) from a panel ninety samples of DBS prepared from anticoagulated venous blood and paired K2-EDTA plasma. The results show high correlation between DBS eluates and wet plasma for five of the six analytes screened, suggesting the Q-plex human micronutrient array can be used with DBS samples, but also highlighting that anticoagulants can have a negative effects on some test components.

Life Course Pathways From Adverse Childhood Experiences to Adult Physical Health: A Structural Equation Model.

OBJECTIVE: This study examines pathways from adverse childhood experiences (ACEs) to physical health, directly and indirectly through lower income, health risk behaviors, social support, and adult adversity within a theoretical framework postulating stress proliferative and biological trajectories of cumulative adversity. METHOD: Data were obtained from 12,549 adult respondents of a state Behavioral Risk Factor Surveillance System survey. Multigroup structural equation modeling elucidated pathways differentiated by sex and age (older/younger than 45). RESULTS: Good model fit was achieved in each test, indicating consistency with stress theorizing that ACEs significantly contribute to poorer physical health through direct and mediated paths. Younger adults evidenced direct ACE pathway to poor health suggesting early biological erosion, whereas paucity of social support among older adults was directly associated. DISCUSSION: Findings indicate that stress process roles in eroding physical health and experience of wellness. Addressing early adversity is an important strategy toward reducing preventable health problems.

Human milk sIgA antibody in relation to maternal nutrition and infant vulnerability in northern Kenya.

BACKGROUND: The maternal buffering hypothesis posits that human lactation biology can buffer milk against the mild-to-moderate malnutrition that occurred routinely in evolutionary history through the mobilization of maternal body reserves. This perspective may provide insights for understanding human milk immune content variation, such as milk sIgA, which protects infants' intestines from microbial colonization and prevents diarrheal disease. OBJECTIVE: To investigate how maternal delivery of sIgA to milk may vary in a way that can buffer milk against maternal malnutrition, while taking into consideration infants' varying needs for immune protection across age or by sex. METHODOLOGY: A cross-sectional study analyzed archived milk specimens from breastfeeding mothers in Ariaal communities of northern Kenya surveyed during the 2006 Horn-of-Africa drought. Multiple regression models for ln-transformed sIgA were constructed using maternal nutrition, infant age/sex and their interactions as predictors. Maternal nutrition variables included iron-deficiency anemia (IDA), vitamin A deficiency (VAD) and mid-upper arm circumference (MUAC). Infant vulnerability was considered high in young age and/or male sex. RESULTS AND IMPLICATIONS: Milk sIgA did not significantly differ by maternal IDA. Milk sIgA increased with infant age and maternal MUAC (n = 202). Significant interactions were observed between infant age and maternal VAD and between infant sex and maternal MUAC, such that milk sIgA content was low for younger infants particularly among VAD mothers, while among mothers with low MUAC, sIgA was lower for male infants. Results imply that mothers' ability to deliver/buffer milk sIgA may be lowered when nutritional stress is combined with high infant vulnerability to infection. LAY SUMMARY: Human milk sIgA antibody content was low for younger infants among vitamin A deficient mothers. Among mothers with small arm-circumference, milk sIgA was lower for sons. Double burden of raising young or male infants with high needs for immune protection and being malnourished, might lower maternal sIgA delivery to milk.

Buffered or impaired: Maternal anemia, inflammation and breast milk macronutrients in northern Kenya.

BACKGROUND: Maternal anemia has adverse consequences for the mother-infant dyad. To evaluate whether and how milk nutrient content may change in ways that could "buffer" infants against the conditions underlying maternal anemia, this study assessed associations between milk macronutrients and maternal iron-deficiency anemia (IDA), non-iron-deficiency anemia (NIDA), and inflammation. METHODS: A secondary analysis of cross-sectional data and milk from northern Kenya was conducted (n = 204). The combination of hemoglobin and transferrin receptor defined IDA/NIDA. Elevated serum C-reactive protein defined acute inflammation. The effects of IDA, NIDA, and inflammation on milk macronutrients were evaluated in regression models. RESULTS: IDA (ß = 0.077, p = .022) and NIDA (ß = 0.083, p = .100) predicted higher total protein (ln). IDA (ß = -0.293, p = .002), NIDA (ß = -0.313, p = .047), and inflammation (ß = -0.269, p = .007) each predicted lower fat (ln); however, anemia accompanying inflammation predicted higher fat (ß = 0.655, p = .007 for IDA and ß = 0.468, p = .092 for NIDA). NIDA predicted higher lactose (ß = 1.020, p = .003). CONCLUSIONS: Milk macronutrient content both increases and decreases in the presence of maternal anemia and inflammation, suggesting a more complicated and dynamic change than simple impairment of nutrient delivery during maternal stress. Maternal fat delivery to milk may be impaired under anemia. Mothers may buffer infant nutrition against adverse conditions or poor maternal health by elevating milk protein (mothers with IDA/NIDA), lactose (mothers with NIDA), or fat (mothers with anemia and inflammation). This study demonstrates the foundational importance of maternal micronutrient health and inflammation or infection for advancing the ecological understanding of human milk nutrient variation.

Health of Philippine Emigrants Study (HoPES): study design and rationale.

BACKGROUND: Immigrants to the United States are usually healthier than their U.S.-born counterparts, yet the health of immigrants declines with duration of stay in the U.S. This pattern is often seen for numerous health problems such as obesity, and is usually attributed to acculturation (the adoption of "American" behaviors and norms). However, an alternative explanation is secular trends, given that rates of obesity have been rising globally. Few studies of immigrants are designed to distinguish the effects of acculturation versus secular trends, in part because most studies of immigrants are cross-sectional, lack baseline data prior to migration, and do not have a comparison group of non-migrants in the country of origin. This paper describes the Health of Philippine Emigrants Study (HoPES), a study designed to address many of these limitations. METHODS: HoPES is a dual-cohort, longitudinal, transnational study. The first cohort consisted of Filipinos migrating to the United States (n = 832). The second cohort consisted of non-migrant Filipinos who planned to remain in the Philippines (n = 805). Baseline data were collected from both cohorts in 2017 in the Philippines, with follow-up data collection planned over 3 years in either the U.S. for the migrant cohort or the Philippines for the non-migrant cohort. At baseline, interviewers administered semi-structured questionnaires that assessed demographic characteristics, diet, physical activity, stress, and immigration experiences. Interviewers also measured weight, height, waist and hip circumferences, blood pressure, and collected dried blood spot samples. DISCUSSION: Migrants enrolled in the study appear to be representative of recent Filipino migrants to the U.S. Additionally, migrant and non-migrant study participants are comparable on several characteristics that we attempted to balance at baseline, including age, gender, and education. HoPES is a unique study that approximates a natural experiment from which to study the effects of immigration on obesity and other health problems. A number of innovative methodological strategies were pursued to expand the boundaries of current immigrant health research. Key to accomplishing this research was investment in building collaborative relationships with stakeholders across the U.S. and the Philippines with shared interest in the health of migrants.

Gender-Based Violence, Physiological Stress, and Inflammation: A Cross-Sectional Study.

BACKGROUND: Female sex workers (FSWs) are at high risk for gender-based violence (GBV) and HIV infection. This study aimed to identify associations between GBV exposure in the past 12 months and biomarkers of physiologic stress and inflammation that may play a role in increased HIV risk among Kenyan FSWs. MATERIALS AND METHODS: Participating women responded to a detailed questionnaire on GBV and mental health. Plasma was collected for assessment of systemic C-reactive protein (CRP) and interleukin-6 (IL-6) levels. Hair proximal to the scalp was collected to measure cortisol concentration. CRP and IL-6 were measured by enzyme-linked immunosorbent assay, and hair cortisol concentration was determined by enzyme immunoassay. Log-transformed biomarker values were compared across GBV exposure categories using Kruskal-Wallis or Wilcoxon rank sum tests. Multivariable linear regression was used to explore associations between recent GBV and hair cortisol concentration. RESULTS: Two hundred eighty-three women enrolled, of whom 112 (39.6%) reported physical, sexual, or emotional violence in the past 12 months, 134 (47.3%) reported more remote exposure, and 37 (13.1%) reported no exposure. CRP and IL-6 levels did not differ across groups (p = 0.57 and p = 0.62, respectively). Among 141 women who provided hair, cortisol concentrations were higher among recently exposed women compared to the other two groups combined (p = 0.02). In multivariable regression, recently exposed women had higher hair cortisol levels than remotely exposed or unexposed women (adjusted beta = 0.52, 95% confidence interval 0.02-1.02, p = 0.04). CONCLUSIONS: While CRP and IL-6 levels did not differ by GBV category, recent GBV was associated with increased hair cortisol concentration. GBV-related increases in cortisol could affect health outcomes and merit study in relation to HIV acquisition risk.

Simultaneous assessment of iodine, iron, vitamin A, malarial antigenemia, and inflammation status biomarkers via a multiplex immunoassay method on a population of pregnant women from Niger.

Deficiencies of vitamin A, iron, and iodine are major public health concerns in many low- and middle-income countries, but information on their status in populations is often lacking due to high costs and logistical challenges associated with assessing micronutrient status. Accurate, user-friendly, and low-cost analytical tools are needed to allow large-scale population surveys on micronutrient status. We present the expansion of a 7-plex protein microarray tool for the simultaneous measurement of up to seven biomarkers with relevance to the assessment of the key micronutrients iron, iodine, and vitamin A, and inflammation and malaria biomarkers: α-1-acid glycoprotein, C-reactive protein, ferritin, retinol binding protein 4, soluble transferrin receptor, thyroglobulin, and histidine-rich protein II. Assay performance was assessed using international reference standards and then verified by comparing the multiplexed and conventional immunoassay results on a training panel of plasma samples collected from US adults. These data were used to assign nominal concentrations to the calibrators of the assay to further improve performance which was then assessed by interrogating plasma samples from a cohort of pregnant women from Niger. The correlation between assays for each biomarker measured from this cohort was typically good, with the exception of thyroglobulin, and the sensitivity ranged from 74% to 93%, and specificity from 81% to 98%. The 7-Plex micronutrient assay has the potential for use as an affordable tool for population surveillance of vitamin A, iron, and iodine deficiencies as well as falciparum malarial parasitemia infectivity and inflammation. The assay is easy-to-use, requires minimal sample volume, and is scalable, rapid, and accurate-needing only a low-cost reader and basic equipment present in most reference laboratory settings and so may be employed by low and middle income countries for micronutrient surveillance to inform on status in key populations. Micronutrient deficiencies including iron, iodine, and vitamin A affect a significant portion of the world's population. Efforts to assess the prevalence of these deficiencies in vulnerable populations are challenging, partly due to measurement tools that are inadequate for assessing multiple micronutrients in large-scale population surveys. We have developed a 7-plex immunoassay for the simultaneous measurement of seven biomarkers relevant to assessing iodine, iron, and vitamin A status, inflammation and Plasmodium falciparum parasitemia by measuring levels of thyroglobulin, ferritin, soluble transferrin receptor, retinol binding protein 4, α-1-acid glycoprotein, C-reactive protein, and histidine-rich protein II. This 7-plex immunoassay technique has potential as a rapid and effective tool for use in large-scale surveys and assessments of nutrition intervention programs in low- and middle-income countries.

Measurement of cortisol in saliva: a comparison of measurement error within and between international academic-research laboratories.

OBJECTIVE: Hundreds of scientific publications are produced annually that involve the measurement of cortisol in saliva. Intra- and inter-laboratory variation in salivary cortisol results has the potential to contribute to cross-study inconsistencies in findings, and the perception that salivary cortisol results are unreliable. This study rigorously estimates sources of measurement variability in the assay of salivary cortisol within and between established international academic-based laboratories that specialize in saliva analyses. One hundred young adults (Mean age: 23.10 years; 62 females) donated 2 mL of whole saliva by passive drool. Each sample was split into multiple- 100 µL aliquots and immediately frozen. One aliquot of each of the 100 participants' saliva was transported to academic laboratories (N = 9) in the United States, Canada, UK, and Germany and assayed for cortisol by the same commercially available immunoassay. RESULTS: 1.76% of the variance in salivary cortisol levels was attributable to differences between duplicate assays of the same sample within laboratories, 7.93% of the variance was associated with differences between laboratories, and 90.31% to differences between samples. In established-qualified laboratories, measurement error of salivary cortisol is minimal, and inter-laboratory differences in measurement are unlikely to have a major influence on the determined values.

Lower incidence of respiratory infections among iron-deficient children in Kilimanjaro, Tanzania.

Objective: We posited a trade-off in iron nutrition, with iron deficiency decreasing risk for infection by depriving infectious agents of iron while increasing risk for infection by compromising immune protection. We described associations between iron deficiency and prevalent and incident infectious disease episodes and cell-mediated immunity (CMI) among 283 children in Kilimanjaro, Tanzania. Methodology: Whole blood specimens were evaluated for hemoglobin and dried blood spots (DBS) were evaluated for biomarkers of iron deficiency (transferrin receptor) and inflammation (C-reactive protein and α1-acid glycoprotein). Prevalent and incident infectious disease episodes were identified by physician's diagnosis. CMI was evaluated as delayed-type hypersensitivity to Candida albicans (DTH-Candida). Associations between iron status and elevated inflammation, prevalent infectious disease episodes and DTH-Candida were described with logistic regression models; associations between iron status and incident infectious disease episodes were described with Cox proportional hazards models. Results: Elevated inflammation and diagnosed infectious diseases were more common among children with iron-deficiency anemia (IDA, severe iron deficiency), but not significantly so. The incidence of infectious disease was lowest among children with moderate iron deficiency (iron-deficient erythropoiesis, IDE); this pattern was most apparent for respiratory infections (aHR: 0.24; p: 0.030). DTH-Candida was not compromised among children with any degree of iron deficiency. Conclusions and implications: We observed no adverse effect of iron deficiency on CMI, but did observe patterns consistent with the hypothesis that moderate iron deficiency protects against respiratory infections and may represent a nutritional adaptation to infectious disease. This suggests that interventions targeting iron deficiency should be coupled with effective infectious disease control measures.

Hay fever, asthma, and eczema and early infectious diseases among children in Kilimanjaro, Tanzania.

OBJECTIVES: To investigate the hygiene (or "old friends") hypothesis in a high-infectious disease (ID) environment, rural Kilimanjaro, Tanzania. METHODS: Among a cross-sectional sample of 2- to 7-year-old children, we collected physician-diagnosed hay fever, asthma, and eczema, history of hospitalization, family size, and household environment information via questionnaire; performed active and passive surveillance for ID; and, evaluated total immunoglobulin E (IgE) and biomarkers of inflammation in dried blood spot specimens. We used regression models to describe patterns in allergic diseases. RESULTS: Complete information was available for 280 children: 12.5% had been diagnosed with hay fever; 18.9% with eczema; 2.1% with asthma. There was a positive association between hay fever and eczema diagnoses (π2 : 4.07; P = 0.044); total IgE was positively associated with eczema (ß: 0.24; P = 0.100) and allergic diseases together (ß: 0.26; P = 0.042). ID were common: the incidence of any ID diagnosis was 28 per 100 children per month. Hay fever was inversely associated with household animals (OR: 0.27; P = 0.006), and positively associated with earth housing materials (OR: 1.93; P = 0.079) and hospitalization in infancy with an ID (3.16; P = 0.066); patterns were similar when allergic disease outcomes were considered together. Few associations between these predictors and eczema or asthma alone were apparent. CONCLUSIONS: Allergic diseases were common among children in Kilimanjaro. The inverse association between household animals and allergy is consistent with the hygiene/old friends hypothesis; however, positive associations between allergic diseases and earth housing materials and early hospitalization with ID bear further explanation.