Helicobacter pylori exposure among the Awajún of the Peruvian Amazon: Prevalence and environmental, social, and biological associations.

OBJECTIVES: Helicobacter pylori (H. pylori)-a gastric bacteria affecting almost 50% of the global population and leading to ulcers and cancer in severe cases-is a growing health concern among Indigenous populations who report a high burden of reported poor general health and gastrointestinal distress. We test hypothesized associations between H. pylori exposure patterns and environmental, social, and biological conditions among a sample of 212 Indigenous Awajún adults (112 males, 100 females, ages 18-65 years) living in the northern Peruvian Amazon. MATERIALS AND METHODS: Dried blood spots were analyzed for H. pylori-specific IgG using a recently developed enzyme-linked immunosorbent assay. Resulting seropositivity rates and antibody concentrations, proxying past exposures to H. pylori were analyzed in relation to relevant environmental (toilet type, floor material, reported water quality), social (household size and education level), and biological (age, sex, BMI, blood pressure, immune and metabolic biomarkers) factors using multivariable regression analyses. RESULTS: We found near ubiquitous seropositivity for H. pylori exposure in our sample (99.1% seropositive). In the regression analyses, elevations in H. pylori antibody concentrations were significantly higher among males compared to females (ß = 0.36, p = 0.01). No associations were found with any other factors. DISCUSSION: Anthropological research in the study communities suggests that the male bias in elevations of H. pylori antibody concentrations is related to cultural and biological factors. Future research is needed to further unravel these biocultural dynamics and determine whether elevations in H. pylori antibody concentrations have clinical relevance for gastrointestinal health outcomes in this population.

Implementation of a minimally invasive cell culture system to measure the regulation of inflammation in a school-based sample of adolescents.

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, IL1ß, 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), IL1ß (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.

Gender Minority Stress, Support, and Inflammation in Transgender and Gender-Nonconforming Youth.

Purpose: Transgender and gender-nonconforming (TGNC) youth often report higher rates of chronic social stressors such as victimization, discrimination, and rejection. Some of these gender-based stressors may have long-range physical health consequences through inflammation pathways. This study evaluates the feasibility and acceptability of adding biological measures of inflammation to an ongoing prospective clinical study of TGNC youth (ages 9-20 years), initiating affirming medical therapy at a large, urban children's hospital (N=56). We also examine the relationship between gender-based sources of stress and support with inflammation. This is the first study to explore how gender identity, social stressors, and social supports may contribute to poorer health in TGNC youth through inflammation and immune dysregulation pathways. Methods: Between October 2016 and August 2018, the study team collected dried blood spot (DBS) samples and health measures during clinical visits. Participants also completed computer-assisted surveys assessing gender minority stress and support during these visits. We used regression analysis to evaluate differences in C-reactive protein (CRP) controlling for demographics, health, gender-based stress, and supports. Results: The results from this study indicate that adding DBS samples to assess inflammation was feasible and acceptable in a clinical sample of TGNC youth seeking affirming-medical interventions. We found an association between greater inflammation and the composite score for greater gender-based stressors and lower gender-based supports using the Gender Minority Stress and Resilience Tool (GMSR); however, we did not find statistically significant differences in CRP associated with any of the individual GMSR subscales assessing various types of gender-based supports or stressors. Conclusion: More research is necessary to evaluate how different sources of gender-based support and stress relate to inflammation with larger sample sizes.

Influence of nutritional status on basal metabolic rates among rural agriculturalists of Ngilo-Ilo, East Java.

OBJECTIVES: Previous research has shown that tropical island populations have reduced basal metabolic rates (BMR) associated with the joint influences of heat stress and undernutrition. This study examines variation in BMR among an indigenous population of Indonesia, and compares these data with those collected from earlier studies in Indonesia. METHODS: Anthropometric dimensions and BMR were measured on a sample of 35 Indonesian adults (28 men, 7 women) from the rural village of Ngilo-Ilo, East Java. RESULTS: Mean measured BMRs (±SD) were 1433 ± 344 kcal/d in men and 1256 ±257 kcal/d in women, and were not significantly different from estimates using the FAO/WHO/UNU predictive questions. Underweight individuals (BMIs <18.5 kg/m2 ) had BMRs that were 7.6% below predicted levels, while those with BMIs ≥18.5 kg/m2 had BMRs that were 8.0% above predicted levels (P < .01). Underweight individuals also had significantly higher respiratory quotients (RQ = .94 vs. .89; P < .05), suggesting lower levels of fat oxidation. Compared to data from previous studies (1929-1979), men of the Ngilo-Ilo sample had similar BMIs (19.8 vs. 19.2 kg/m2 ), but higher BMRs, after adjusting for age and body weight (+2.1% vs. -5.6%; P < .05). CONCLUSIONS: Among the agriculturalists of Ngilo-Ilo, measured BMRs were low, but not significantly different from those predicted by the FAO/WHO/UNU equations. Among subjects of this sample and from earlier studies, poorer physical nutritional status was associated with reduced BMRs. These results suggest that chronic energy stress has consistently shaped metabolic function among Indonesian rural populations.

Validation of endotoxin-core antibodies in dried blood spots as a measure of environmental enteropathy and intestinal permeability.

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.

Measurement of leptin in dried blood spot samples.

Leptin is important in a wide range of physiological processes, but logistical constraints associated with venipuncture blood collection have limited research on leptin in diverse, community-based settings. The aim of this short report is to present and validate an enzyme immunoassay method for quantifying leptin in samples of capillary whole blood collected from a simple finger prick and dried on filter paper. The method was evaluated through analysis of precision, reliability, stability, and comparisons with matched plasma and blood spot samples. We report acceptable levels of assay precision and reliability, and good agreement between results obtained from matched plasma and blood spot samples (r = 0.976, P < 0.001). Leptin concentrations begin to deteriorate after only 3 days at room temperature. Thus, care should be taken to refrigerate or freeze samples promptly. The relative ease of blood spot sample collection may facilitate research on leptin in a wider range of cultural and ecological settings.