Common Variants in the TMPRSS6 Gene Alter Hepcidin but not Plasma Iron in Response to Oral Iron in Healthy Gambian Adults: A Recall-by-Genotype Study.

BACKGROUND: The role of genetic determinants in mediating iron status in Africans is not fully understood. Genome-wide association studies in non-African populations have revealed genetic variants in the transmembrane protease serine 6 gene (TMPRSS6) that are associated with the risk of anemia. OBJECTIVES: To investigate the effects of risk alleles for low iron status, namely TMPRSS6 rs2235321, rs855791, and rs4820268, on responses to oral iron in healthy Gambian adults. METHODS: Using a recall-by-genotype design, participants were selected from a pregenotype cohort of 3000 individuals in the Keneba Biobank (Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine). Participants were invited to participate in the study based on 9 genotype combinations obtained from 3 TMPRSS6 single nucleotide polymorphisms (SNPs): rs2235321, rs855791, and rs4820268. The participants fasted overnight and then ingested a single oral dose of ferrous sulfate (130 mg elemental iron). Blood samples were collected prior to iron ingestion and at 2 and 5 h after the oral iron dose. The effects of genotype on hepcidin and plasma iron parameters were assessed. RESULTS: A total of 251 individuals were enrolled. Homozygous carriers of the major TMPRSS6 alleles at each of the SNPs had higher plasma hepcidin at baseline (rs2235321: GG compared with AA = 9.50 compared with 6.60 ng/ml, P = 0.035; rs855791: GG compared with AG = 9.50 compared with 4.96 ng/mL, P = 0.015; rs4820268: AA compared with GG = 9.50 compared with 3.27 ng/mL,  P = 0.002) and at subsequent timepoints. In most subjects, hepcidin concentrations increased following iron ingestion (overall group mean = 4.98 ± 0.98 ng/mL at 5 h, P < 0.001), but double heterozygotes at rs2235321 and rs855791 showed no increase (0.36 ± 0.40 ng/mL at 5 h, P = 0.667). CONCLUSIONS: This study revealed that common TMPRSS6 variants influence hepcidin concentrations, but not iron status indicators either at baseline or following a large oral dose of iron. These results suggest that genetic variations in the TMPRSS6 gene are unlikely to be important contributors to variations in iron status in Africans.This study was registered at clinicaltrials.gov (# NCT03341338)

It takes a village: Caregiver diversity and language contingency in the UK and rural Gambia

INTRODUCTION: There is substantial diversity within and between contexts globally in caregiving practices and family composition, which may have implications for the early interaction’s infants engage in. We draw on data from the Brain Imaging for Global Health (BRIGHT, www.globalfnirs.org/the-bright-project) project, which longitudinally examined infants in the UK and in rural Gambia, West Africa. In The Gambia, households are commonly characterized by multigenerational, frequently polygamous family structures, which, in part, is reflected in the diversity of caregivers a child spends time with. In this paper, we aim to 1) evaluate and validate the Language Environment Analysis (LENA) for use in the Mandinka speaking families in The Gambia, 2) examine the nature (i.e., prevalence of turn taking) and amount (i.e., adult and child vocalizations) of conversation that infants are exposed to from 12 to 24 months of age and 3) investigate the link between caregiver diversity and child language outcomes, examining the mediating role of contingent turn taking. METHOD: We obtained naturalistic seven-hour-long LENA recordings at 12, 18 and 24 months of age from a cohort of N = 204 infants from Mandinka speaking households in The Gambia and N = 61 infants in the UK. We examined developmental changes and site differences in LENA counts of adult word counts (AWC), contingent turn taking (CTT) and child vocalizations (CVC). In the larger and more heterogenous Gambian sample, we also investigated caregiver predictors of turn taking frequency. We hereby examined the number of caregivers present over the recording day and the consistency of caregivers across two subsequent days per age point. We controlled for children’s cognitive development via the Mullen Scales of Early Learning (MSEL). RESULTS: Our LENA validation showed high internal consistency between the human coders and automated LENA outputs (Cronbach’s alpha’s all >.8). All LENA counts were higher in the UK compared to the Gambian cohort. In The Gambia, controlling for overall neurodevelopment via the MSEL, CTT at 12 and 18 months predicted CVC at 18 and 24 months. Caregiver consistency was associated with CTT counts at 18 and 24 months. The number of caregivers and CTT counts showed an inverted u-shape relationship at 18 and 24 months, with an intermediate number of caregivers being associated with the highest CTT frequencies. Mediation analyses showed a partial mediation by number of caregivers and CTT and 24-month CVC. DISCUSSION: The LENA provided reliable estimates for the Mandinka language in the home recording context. We showed that turn taking is associated with subsequent child vocalizations and explored contextual caregiving factors contributing to turn taking in the Gambian cohort

Maternal acceptability of iron supplementation in young breastfed rural Gambian infants

Introduction A recent analysis of Gambian infants showed that plasma iron concentrations decline rapidly from birth to levels below the 95% reference range within 5 months of age. To address this issue, a clinical trial was initiated to assess the efficacy of early iron supplementation in breastfed infants under 6 months of age (‘Iron Babies’; NCT04751994). To understand if such an intervention is feasible for scaleup, the acceptability, through the lens of local stakeholders and mothers (as the primary caregiver), must be considered. Methods An embedded qualitative study, therefore, explored acceptability through focus group discussions with local stakeholders and interviews with mothers. Four focus group discussions with local stakeholders (n = 19) and individual interviews (n = 14) with mothers whose infants were enrolled in the clinical trial were conducted. Qualitative data were analysed with respect to an implementation acceptability framework using Template Analysis. Results From the focus group discussions, there was a general sense of enthusiasm for the intervention, but also a concern due to confusion around nutritional messaging. The intervention was acceptable to mothers with limited mention of side effects and enthusiasm for participating in clinical trials on iron supplementation. However, when looking at scaleup, there were mixed opinions on the practicality of daily supplementation, as well as concerns around costs. In addition, it was suggested that proper dissemination of information and inclusion of all family members in decision-making, especially fathers, is key to acceptability. Conclusion There was no indication that stakeholders or mothers were resistant to iron supplementation of breastfed infants

Menstrual hygiene management practices and associated health outcomes among school-going adolescents in rural Gambia.

Inadequate menstrual hygiene management (MHM) practices have been associated with adverse health outcomes. This study aimed to describe MHM practices among schoolgirls from rural Gambia and assess risk factors associated with urogenital infections and depressive symptoms. A cross-sectional study was conducted among adolescent schoolgirls in thirteen schools in rural Gambia. A questionnaire was used to collect information on socio-demographics, MHM practices and clinical symptoms of reproductive and urinary tract infections (UTIs). A modified Beck Depression Inventory-II was used to screen for depressive symptoms. Mid-stream urine samples were collected to assess for UTIs. Modified Poisson regression analysis was used to determine risk factors for symptoms of urogenital infections and depression among adolescent girls. Three hundred and fifty-eight girls were recruited. Although, 63% of the girls attended schools providing free disposable pads, reusable cloths/towels were the commonest absorbent materials used. Heavy menstrual bleeding was associated with depressive symptoms (adjusted prevalence ratio, aPR 1.4 [95% CI 1.0, 1.9]), while extreme menstrual pain (aPR 1.3 [95% CI 1.2, 1,4]), accessing sanitary pads in school (aPR 1.4 [95% CI 1.2, 1.5]) and less access to functional water source at school (aPR 1.4 [95% CI 1.3, 1.6]) were associated with UTI symptoms. Conversely, privacy in school toilets (aPR 0.6 [95% CI 0.5, 0.7]) was protective for UTI symptoms. Heavy menstrual bleeding (aPR 1.4 [95% CI 1.1, 2.0]) and taking <30 minutes to collect water at home were associated with RTI symptoms (aPR 1.2 [95% CI 1.0, 1.5]) while availability of soap in school toilets (aPR 0.6 [95% CI 0.5, 0.8] was protective for RTI symptoms. Interventions to ensure that schoolgirls have access to private sanitation facilities with water and soap both at school and at home could reduce UTI and RTI symptoms. More attention is also needed to support girls with heavy menstrual bleeding and pain symptoms

Circulation of respiratory viruses during the COVID-19 pandemic in The Gambia

Background: In many countries, non-pharmaceutical interventions to limit severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission resulted in significant reductions in other respiratory viruses. However, similar data from Africa are limited. We explored the extent to which viruses such as influenza and rhinovirus co-circulated with SARS-CoV-2 in The Gambia during the COVID-19 pandemic.  Methods: Between April 2020 and March 2022, respiratory viruses were detected using RT-PCR in nasopharyngeal swabs from 1397 participants with influenza-like illness. An assay to detect SARS-CoV-2 and a viral multiplex RT-PCR assay was used as previously described  to detect influenza A and B, respiratory syncytial virus (RSV) A and B, parainfluenza viruses 1-4, human metapneumovirus (HMPV), adenovirus, seasonal coronaviruses (229E, OC43, NL63) and human rhinovirus. Results: Overall virus positivity was 44.2%, with prevalence higher in children 50 years (39.9%), p50 years (24.3%), p50 years (6.3%), p<0.0001. Four SARS-CoV-2 waves occurred, with 36.1%-52.4% SARS-CoV-2 positivity during peak months. Influenza infections were observed in both 2020 and 2021 during the rainy season as expected (peak positivity 16.4%-23.5%). Peaks of rhinovirus were asynchronous to the months when SARS-CoV-2 and influenza peaked. Conclusion: Our data show that many respiratory viruses continued to circulate during the COVID-19 pandemic in The Gambia, including human rhinoviruses, despite the presence of NPIs during the early stages of the pandemic, and influenza peaks during expected months

Bacteremia in Childhood Life-Threatening Infections in Urban Gambia: EUCLIDS in West Africa

Background: The limited availability of microbiology services in sub-Saharan Africa impedes accurate diagnosis of bacterial pathogens and understanding of trends in prevalence and antibiotic sensitivities. We aimed to characterize bacteremia among hospitalized children in The Gambia and to identify factors associated with bacteremia and mortality. Methods: We prospectively studied children presenting wit

Identification of regulatory variants associated with genetic susceptibility to meningococcal disease

Non-coding genetic variants play an important role in driving susceptibility to complex diseases but their characterization remains challenging. Here, we employed a novel approach to interrogate the genetic risk of such polymorphisms in a more systematic way by targeting specific regulatory regions relevant for the phenotype studied. We applied this method to meningococcal disease susceptibility, using the DNA binding pattern of RELA - a NF-kB subunit, master regulator of the response to infection - under bacterial stimuli in nasopharyngeal epithelial cells. We designed a custom panel to cover these RELA binding sites and used it for targeted sequencing in cases and controls. Variant calling and association analysis were performed followed by validation of candidate polymorphisms by genotyping in three independent cohorts. We identified two new polymorphisms, rs4823231 and rs11913168, showing signs of association with meningococcal disease susceptibility. In addition, using our genomic data as well as publicly available resources, we found evidences for these SNPs to have potential regulatory effects on ATXN10 and LIF genes respectively. The variants and related candidate genes are relevant for infectious diseases and may have important contribution for meningococcal disease pathology. Finally, we described a novel genetic association approach that could be applied to other phenotypes

Identification of regulatory variants associated with genetic susceptibility to meningococcal disease.

Non-coding genetic variants play an important role in driving susceptibility to complex diseases but their characterization remains challenging. Here, we employed a novel approach to interrogate the genetic risk of such polymorphisms in a more systematic way by targeting specific regulatory regions relevant for the phenotype studied. We applied this method to meningococcal disease susceptibility, using the DNA binding pattern of RELA - a NF-kB subunit, master regulator of the response to infection - under bacterial stimuli in nasopharyngeal epithelial cells. We designed a custom panel to cover these RELA binding sites and used it for targeted sequencing in cases and controls. Variant calling and association analysis were performed followed by validation of candidate polymorphisms by genotyping in three independent cohorts. We identified two new polymorphisms, rs4823231 and rs11913168, showing signs of association with meningococcal disease susceptibility. In addition, using our genomic data as well as publicly available resources, we found evidences for these SNPs to have potential regulatory effects on ATXN10 and LIF genes respectively. The variants and related candidate genes are relevant for infectious diseases and may have important contribution for meningococcal disease pathology. Finally, we described a novel genetic association approach that could be applied to other phenotypes

Life-threatening infections in children in Europe (the EUCLIDS Project): a prospective cohort study

Background: Sepsis and severe focal infections represent a substantial disease burden in children admitted to hospital. We aimed to understand the burden of disease and outcomes in children with life-threatening bacterial infections in Europe. Methods: The European Union Childhood Life-threatening Infectious Disease Study (EUCLIDS) was a prospective, multicentre, cohort study done in six countries in Europe. Patients aged 1 month to 18 years with sepsis (or suspected sepsis) or severe focal infections, admitted to 98 participating hospitals in the UK, Austria, Germany, Lithuania, Spain, and the Netherlands were prospectively recruited between July 1, 2012, and Dec 31, 2015. To assess disease burden and outcomes, we collected demographic and clinical data using a secured web-based platform and obtained microbiological data using locally available clinical diagnostic procedures. Findings: 2844 patients were recruited and included in the analysis. 1512 (53·2%) of 2841 patients were male and median age was 39·1 months (IQR 12·4–93·9). 1229 (43·2%) patients had sepsis and 1615 (56·8%) had severe focal infections. Patients diagnosed with sepsis had a median age of 27·6 months (IQR 9·0–80·2), whereas those diagnosed with severe focal infections had a median age of 46·5 months (15·8–100·4; p<0·0001). Of 2844 patients in the entire cohort, the main clinical syndromes were pneumonia (511 [18·0%] patients), CNS infection (469 [16·5%]), and skin and soft tissue infection (247 [8·7%]). The causal microorganism was identified in 1359 (47·8%) children, with the most prevalent ones being Neisseria meningitidis (in 259 [9·1%] patients), followed by Staphylococcus aureus (in 222 [7·8%]), Streptococcus pneumoniae (in 219 [7·7%]), and group A streptococcus (in 162 [5·7%]). 1070 (37·6%) patients required admission to a paediatric intensive care unit. Of 2469 patients with outcome data, 57 (2·2%) deaths occurred: seven were in patients with severe focal infections and 50 in those with sepsis. Interpretation: Mortality in children admitted to hospital for sepsis or severe focal infections is low in Europe. The disease burden is mainly in children younger than 5 years and is largely due to vaccine-preventable meningococcal and pneumococcal infections. Despite the availability and application of clinical procedures for microbiological diagnosis, the causative organism remained unidentified in approximately 50% of patients