Environmental determinants of total IgE among school children living in the rural Tropics: importance of geohelminth infections and effect of anthelmintic treatment

BACKGROUND: The environmental factors that determine the elevated levels of polyclonal IgE observed in populations living in the Tropics are poorly understood but may include geohelminth infections. We investigated the association between geohelminth infections and total IgE levels in school children in rural tropical Ecuador, and assessed the effect on IgE of repeated anthelmintic treatments over a period of 12 months. The study was nested within a cluster-randomized study that randomized 68 schools to receive either 400 mg of albendazole every 2 months over a year or no treatment. We studied random samples of children completing follow-up and representing four groups stratified by the presence of geohelminth infection at baseline and treatment allocation. We measured levels of total IgE and anti-A. lumbricoides IgG (used as a measure of past and current geohelminth infectious exposure) in blood samples collected at the start of the study and after 12 months. RESULTS: We observed elevated levels of total IgE (compared to standard reference values) at the start of the study in this population of school children (geometric mean, 1,004 IU/mL, range 12 to 22,608 IU/mL)) and baseline IgE levels were strongly associated with parameters of geohelminth infection but not with age, nutritional and socioeconomic status. After 12 months, levels of IgE fell significantly in the treatment (by 35.1%) and no treatment (by 10.4%) groups, respectively, but the fall was significantly greater in the treatment group. Falls in IgE were independently associated with albendazole treatment, having a baseline geohelminth infection and with high baseline levels of anti-A. lumbricoides IgG. Increases in IgE at 12 months were associated with the presence of geohelminth infections and increasing levels of anti-A. lumbricoides IgG at 12 months independent of treatment allocation. CONCLUSION: The data provide evidence that geohelminth infections are an important determinant of total IgE in school children in the rural Tropics and that periodic anthelmintic treatments over 12 months are associated with reductions in IgE. The failure of anthelmintic treatment to reduce IgE levels to that considered normal in industrialized countries may be attributed to continued exposure of children to geohelminths or to the effects of infections in early life in programming a long-lasting Th2-biassed immunity

Migration and allergic diseases in a rural area of a developing country.

Submitted by Ana Maria Fiscina Sampaio ([email protected]) on 2017-02-10T17:02:09Z No. of bitstreams: 1 Rodriguez A Migration and allergic....pdf: 149809 bytes, checksum: dd2e77d239dd95d5fbf01198a195d13a (MD5)Approved for entry into archive by Ana Maria Fiscina Sampaio ([email protected]) on 2017-02-10T17:40:30Z (GMT) No. of bitstreams: 1 Rodriguez A Migration and allergic....pdf: 149809 bytes, checksum: dd2e77d239dd95d5fbf01198a195d13a (MD5)Made available in DSpace on 2017-02-10T17:40:30Z (GMT). No. of bitstreams: 1 Rodriguez A Migration and allergic....pdf: 149809 bytes, checksum: dd2e77d239dd95d5fbf01198a195d13a (MD5) Previous issue date: 2016Wellcome Trust (grant nos. 072405/Z/03/Z and 088862/Z/09/Z).Laboratorio de Investigaci on FEPIS. Quinind e, Esmeraldas Province, Ecuador / Faculty of Epidemiology and Population Health. London School of Hygiene and Tropical Medicine. London, United Kingdom / Universidad Internacional del Ecuador. Facultad de Ciencias Medicas de la Salud y la Vida. Quito, EcuadorLaboratorio de Investigaci on FEPIS. Quinind e, Esmeraldas Province, EcuadorLaboratorio de Investigaci on FEPIS. Quinind e, Esmeraldas Province, EcuadorFaculty of Epidemiology and Population Health. London School of Hygiene and Tropical Medicine. London, United KingdomFundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Instituto de Saúde Coletiva. Salvador, BA, BrasilLaboratorio de Investigaci on FEPIS. Quinind e, Esmeraldas Province, Ecuador / Universidad Internacional del Ecuador. Facultad de Ciencias Medicas de la Salud y la Vida. Quito, Ecuador / St George’s University of London. Institute of Infection and Immunity. London, United Kingdo

Risk factors for asthma and allergy associated with urban migration: background and methodology of a cross-sectional study in Afro-Ecuadorian school children in Northeastern Ecuador (Esmeraldas-SCAALA Study)

BACKGROUND: Asthma and allergic diseases are becoming increasingly frequent in children in urban centres of Latin America although the prevalence of allergic disease is still low in rural areas. Understanding better why the prevalence of asthma is greater in urban migrant populations and the role of risk factors such as life style and environmental exposures, may be key to understand what is behind this trend. METHODS/DESIGN: The Esmeraldas-SCAALA (Social Changes, Asthma and Allergy in Latin America) study consists of cross-sectional and nested case-control studies of school children in rural and urban areas of Esmeraldas Province in Ecuador. The cross-sectional study will investigate risk factors for atopy and allergic disease in rural and migrant urban Afro-Ecuadorian school children and the nested case-control study will examine environmental, biologic and social risk factors for asthma among asthma cases and non-asthmatic controls from the cross-sectional study. Data will be collected through standardised questionnaires, skin prick testing to relevant aeroallergen extracts, stool examinations for parasites, blood sampling (for measurement of IgE, interleukins and other immunological parameters), anthropometric measurements for assessment of nutritional status, exercise testing for assessment of exercise-induced bronchospasm and dust sampling for measurement of household endotoxin and allergen levels. DISCUSSION: The information will be used to identify the factors associated with an increased risk of asthma and allergies in migrant and urbanizing populations, to improve the understanding of the causes of the increase in asthma prevalence and to identify potentially modifiable factors to inform the design of prevention programmes to reduce the risk of allergy in urban populations in Latin America

Lifestyle domains as determinants of wheeze prevalence in urban and rural schoolchildren in Ecuador: cross sectional analysis.

BACKGROUND: The acquisition of a modern lifestyle may explain variations in asthma prevalence between urban and rural areas in developing countries. However, the effects of lifestyle on asthma have been investigated as individual factors with little consideration given to the effects of lifestyle as a set of attributes. The aim of the present study was to identify modern lifestyle domains and assess how these domains might explain wheeze prevalence in urban and rural areas. METHODS: We analysed data from cross-sectional studies of urban and rural schoolchildren in Esmeraldas Province, Ecuador. Variables were grouped as indicators of socioeconomic factors, sedentarism, agricultural activities and household characteristics to represent the main lifestyle features of the study population. We used multiple correspondence analyses to identify common lifestyle domains and cluster analysis to allocate children to each domain. We evaluated associations between domains and recent wheeze by logistic regression. RESULTS: We identified 2-3 lifestyle domains for each variable group. Although wheeze prevalence was similar in urban (9.4%) and rural (10.3%) schoolchildren, lifestyle domains presented clear associations with wheeze prevalence. Domains relating to home infrastructure (termed transitional, rudimentary, and basic urban) had the strongest overall effect on wheeze prevalence in both urban (rudimentary vs. basic urban, OR = 2.38, 95% CI 1.12-5.05, p = 0.024) and rural areas (transitional vs. basic urban, OR = 2.02, 95% CI 1.1-3.73, p = 0.024; rudimentary vs. basic urban, OR = 1.88, 95% CI 1.02-3.47, p = 0.043). A high level of sedentarism was associated with wheeze in the rural areas only (OR = 1.64, 95% CI 1.23-2.18, p = 0.001). CONCLUSIONS: We identified lifestyle domains associated with wheeze prevalence, particularly living in substandard housing and a high level of sedentarism. Such factors could be modified through programmes of improved housing and education. The use of lifestyle domains provides an alternative methodology for the evaluation of variations in wheeze prevalence in populations with different levels of development

Effects of chronic ascariasis and trichuriasis on cytokine production and gene expression in human blood: a cross-sectional study.

Background Chronic soil-transmitted helminth (STH) infections are associated with effects on systemic immune responses that could be caused by alterations in immune homeostasis. To investigate this, we measured the impact in children of STH infections on cytokine responses and gene expression in unstimulated blood. Methodology/Principal Findings Sixty children were classified as having chronic, light, or no STH infections. Peripheral blood mononuclear cells were cultured in medium for 5 days to measure cytokine accumulation. RNA was isolated from peripheral blood and gene expression analysed using microarrays. Different infection groups were compared for the purpose of analysis: STH infection (combined chronic and light vs. uninfected groups) and chronic STH infection (chronic vs. combined light and uninfected groups). The chronic STH infection effect was associated with elevated production of GM-CSF (P = 0.007), IL-2 (P = 0.03), IL-5 (P = 0.01), and IL-10 (P = 0.01). Data reduction suggested that chronic infections were primarily associated with an immune phenotype characterized by elevated IL-5 and IL-10, typical of a modified Th2-like response. Chronic STH infections were associated with the up-regulation of genes associated with immune homeostasis (IDO, P = 0.03; CCL23, P = 0.008, HRK, P = 0.005), down-regulation of microRNA hsa-let-7d (P = 0.01) and differential regulation of several genes associated with granulocyte-mediated inflammation (IL-8, down-regulated, P = 0.0002; RNASE2, up-regulated, P = 0.009; RNASE3, up-regulated, p = 0.03). Conclusions/Significance Chronic STH infections were associated with a cytokine response indicative of a modified Th2 response. There was evidence that STH infections were associated with a pattern of gene expression suggestive of the induction of homeostatic mechanisms, the differential expression of several inflammatory genes and the down-regulation of microRNA has-let-7d. Effects on immune homeostasis and the development of a modified Th2 immune response during chronic STH infections could explain the systemic immunologic effects that have been associated with these infections such as impaired immune responses to vaccines and the suppression of inflammatory diseases

Temporary restorative treatment in children and adolescents with amelogenesis imperfecta: Scoping review.

Background: Amelogenesis imperfecta (AI) is a group of disorders that affect the enamel of the teeth, either in quality or quantity. This alteration causes sensitivity and is associated with factors that could affect the strength of the adhesive bond of the restorative material. Aim: To review the literature regarding the most used temporary restorative treatment in children and adolescents with AI. Methods: This scoping review aimed to include case reports, literature reviews and original studies that evaluated restorative materials for the teeth of children and adolescents with AI. Editorials, meeting abstracts and letters to the editor were excluded. The following electronic databases were used: Medline (Ovid), PubMed, Ebsco, Scopus (Elsevier) and Web of Science (Thomson Reuters). Manual searches in the reference lists of the included articles were also carried out. Finally, a search in Google Scholar restricted to the first 100 hits was performed. Duplicates were eliminated upon identification. The search covered a period between the years of 2011 and 2016. PRISMA guidelines were used for reporting the review. The evidence ranking was carried out by means of the Oxford criteria. Results: Six articles met the eligibility criteria and were included in this scoping review. Three articles were case reports, one was a review and two were original studies. For the treatment of AI, direct or indirect composite resins were the most commonly used material of choice in the retrieved studies because they demonstrate greater longevity, aesthetics and function compared to the other materials used. Conclusions: Among children and adolescents with AI, the temporary restorative treatment that demonstrated better long-term results in permanent teeth was the direct and indirect composite resins. However, high quality studies should be conducted to confirm the results presented herein

Effect of albendazole treatments on the prevalence of atopy in children living in communities endemic for geohelminth parasites: a cluster-randomised trial.

BACKGROUND: Epidemiological studies have shown inverse associations between geohelminth (intestinal helminth) infection and atopy, leading to the suggestion that geohelminths might protect against allergy. Periodic deworming of school children with anthelmintics is a widely implemented intervention and has raised concerns that such programmes could increase allergy. We investigated the effect of repeated anthelmintic treatments with albendazole over 12 months on the prevalence of atopy and clinical indices of allergy. METHODS: We did a cluster-randomised controlled trial in schoolchildren from 68 rural schools. Children were randomly assigned by school to either albendazole (34 schools, 1164 children) every 2 months for 12 months, or to no intervention (34 schools, 1209 children). The intervention schools received a total of seven albendazole treatments. The primary outcome was atopy at 12 months (allergen skin-test reactivity), and analysis was by intention-to-treat for whole-school analyses and per protocol for children. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN61195515. FINDINGS: Data for analysis were available for all schools and from 67.4% (784 of 1164) and 70.1% (848 of 1209) of children in albendazole and no-treatment groups, respectively. Albendazole treatment caused large reductions in geohelminth prevalence over the study period (adjusted odds ratio 0.13, 95% CI 0.09-0.19, p<0.001), but there was no evidence that treatment was associated with an increase in atopy prevalence (0.97, 0.68-1.39, p=0.862), or clinical allergy (wheeze, 1.07, 0.54-2.11, p=0.848) in the albendazole compared with the no-treatment group. INTERPRETATION: We saw no increase in the prevalence of atopy or clinical allergy associated with albendazole treatment. Deworming programmes for schoolchildren are unlikely to be accompanied by an increase in allergy