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BACKGROUND: The prevalence of allergy-related diseases (ARDs), including rhinitis, allergic conjunctivitis and eczema, is on the increase globally. The causes of this increase are not well established. OBJECTIVES: To investigate the risk factors associated with ARDs among schoolchildren in Uganda. METHODS: We conducted a secondary data analysis of a large asthma case-control study involving 1700 schoolchildren, 5-17 years, in urban Uganda. ARDs were defined according to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Skin prick testing (SPT) was conducted using standard procedures and allergen-specific IgE (asIgE) using ImmunoCAP® . We employed inverse probability weighted analysis to generate estimated prevalence data and weighted odds ratios. RESULTS: The lifetime estimated weighted prevalence of reported rhinitis, allergic conjunctivitis and eczema was 43.3%, 39.5% and 13.5%; weighted prevalence in 12 months was 10.1%, 9.1% and 2.3%, respectively. There was overlap of ARDs, with 66.3% of 1193 schoolchildren who reported having ever an ARDs (including asthma) reporting two or more. Risk factors associated with reported rhinitis in the last 12 months were city residence at birth [adjusted odds ratio (95% confidence interval) 2.66 (1.42-4.99) compared to rural]; father's [2.62 (1.79-3.83)] and mother's history of allergic disease [2.12 (1.48-3.02)]; frequent de-worming in the last 12 months [2.01 (1.30-3.11), ≥2 versus none]; current high frequency of 'trucks passing on the street near home' [2.59 (1.48-4.52), 'almost all the time' versus rarely] and positive SPT [1.54 (1.09-2.18)] but not asIgE [1.38 (0.60-3.15)]. The same pattern of risk factors was observed for allergic conjunctivitis and eczema. CONCLUSION: We found extensive multi-morbidity of, and overlap in the risk factors for, rhinitis, conjunctivitis and eczema-similar to asthma risk factors-among schoolchildren in urban Uganda. This suggests a similar underlying cause for all ARDs, associated with exposure to urban lifestyles and environment in Uganda.
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Conjuntivitis Alérgica/epidemiología , Dermatitis Atópica/epidemiología , Dinámica Poblacional/estadística & datos numéricos , Rinitis Alérgica/epidemiología , Población Urbana/estadística & datos numéricos , Adolescente , Asma/epidemiología , Estudios de Casos y Controles , Niño , Preescolar , Comorbilidad , Femenino , Humanos , Masculino , Padres , Prevalencia , Rinitis/epidemiología , Factores de Riesgo , Uganda/epidemiologíaRESUMEN
Data on asthma aetiology in Africa are scarce. We investigated the risk factors for asthma among schoolchildren (5-17 years) in urban Uganda. We conducted a case-control study, among 555 cases and 1115 controls. Asthma was diagnosed by study clinicians. The main risk factors for asthma were tertiary education for fathers (adjusted OR (95% CI); 2.32 (1.71-3.16)) and mothers (1.85 (1.38-2.48)); area of residence at birth, with children born in a small town or in the city having an increased asthma risk compared to schoolchildren born in rural areas (2.16 (1.60-2.92)) and (2.79 (1.79-4.35)), respectively; father's and mother's history of asthma; children's own allergic conditions; atopy; and cooking on gas/electricity. In conclusion, asthma was associated with a strong rural-town-city risk gradient, higher parental socio-economic status and urbanicity. This work provides the basis for future studies to identify specific environmental/lifestyle factors responsible for increasing asthma risk among children in urban areas in LMICs.
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Contaminantes Atmosféricos/efectos adversos , Alérgenos/efectos adversos , Asma/diagnóstico , Asma/epidemiología , Adolescente , Contaminantes Atmosféricos/inmunología , Alérgenos/inmunología , Asma/etiología , Asma/inmunología , Estudios de Casos y Controles , Niño , Preescolar , Escolaridad , Femenino , Humanos , Estilo de Vida , Masculino , Padres/educación , Factores de Riesgo , Población Rural , Uganda/epidemiología , Población Urbana , UrbanizaciónRESUMEN
Background: Children from low- and middle-income countries have poor asthma control, mainly because of poor management. The extent of this problem in Uganda is not well known, but such information would be useful to guide policy and practice. We therefore conducted a cross-sectional study among schoolchildren with asthma in urban Uganda, to assess the level of asthma control and management. Methods: Schoolchildren aged 5-17 years were enrolled, asthma was diagnosed by the study medical team. Asthma control was assessed using the Asthma Control Test and the childhood Asthma Control Test. Data on previous asthma management was obtained using interviewer-led questionnaires. Data were analysed using multiple linear and multiple logistic regression. Results: We enrolled 561 children with asthma, of whom only 56% had ever had an asthma diagnosis. We categorised asthma as well-controlled (55.5%), partly-controlled (29.5%) and poorly-controlled (15.0%). Poor asthma control was associated with increasing age (adjusted regression coefficient [95% confidence interval], p-value: -1.07 [-1.20, -0.94], p<0.0001), concurrent allergic rhinitis (-1.33 [-2.28, -0.38], p=0.006), and city residence in early life (-1.99 [-3.69, -0.29], p=0.06). Regular use of inhaled asthma medication in the last 12 months was very low; 18.1% for salbutamol and 6.7% for inhaled corticosteroids. The main barriers to inhaled asthma medication use were lack of prescription (47.6%) and inaccurate diagnosis (38.8%). Increased inhaler use was associated with tertiary education of the fathers (adjusted odds ratio [95% confidence interval], p-value: 5.19 [2.39-11.28], p<0.0001), city residence in early life (4.66 [1.79-12.43], 0.002) and an asthma diagnosis prior to enrolment (11.39 [6.35-20.43], p<0.0001). Conclusions: This study confirms that children with asthma in Uganda generally have inadequate asthma control, which is attributable to poor asthma management. This could be improved through re-training of medical workers and patient education, and by increasing availability and affordability of essential asthma medications.
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Background: A more effective vaccine for tuberculosis (TB) is a global public health priority. Vaccines under development will always need evaluation in endemic settings, most of which have limited resources. Adolescents are an important target population for a new TB vaccine and for other vaccines which are relevant at school-age. However, in most endemic settings there is limited experience of trials of investigational products among adolescents, and adolescents are not routinely vaccinated. Methods: We used Modified vaccinia Ankara-expressing Ag85A (MVA85A), a well-tolerated candidate vaccine for tuberculosis, to assess the effect of Schistosoma mansoni infection on vaccine immunogenicity among Ugandan adolescents in primary school. We describe here the challenges and lessons learned in designing and implementing this first clinical trial among Ugandan adolescents using a non-licensed vaccine. Results: The school based immunization study was feasible and adhered to Good Clinical Practice principles. Engagement with the community and all stakeholders was critical for successful implementation of the trial. Creative and adaptable strategies were used to address protocol-specific, operational and logistical challenges. This study provided lessons and solutions that can be applied to other trials among adolescents in similar settings elsewhere, and to school-based immunization programs. Conclusion: Sufficient time and resources should be planned for community preparation and sensitization to ensure buy in and acceptance of a project of this kind. This trial shows that challenges to implementing early field trials in Africa are not insurmountable and that necessary well-planned high-quality ethical trials are feasible and should be encouraged. Trial Registration: ClinicalTrials.gov NCT02178748 03/06/2014.
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Background: The home environment is reported to contribute significantly to children's developing cognitive skills. However, it is not yet evident whether this role prevails in the context of extreme poverty and frequent ill-health. We therefore investigated the role of the home environment in Ugandan children taking into account the frequent infections and extreme poverty in which they lived. Methods: Cognitive abilities of 163 5-year-old children were assessed. Home environments of these children, their health status and family socioeconomic status (SES) were assessed respectively using the EC-HOME, anthropometry and illnesses, and traditional SES measures. Structural equation analyses compared five models on the influence of the home environment, SES, and child health on the cognitive scores. Results: The model in which the home environment mediates the combined influence of SES and child health on cognitive performance showed a particularly good fit to the data compared with the four alternative models, i.e. those in which the HOME, SES and health independently influence cognitive performance. Conclusions: Home environments providing cognitive stimulation can enable children to overcome effects of major adverse life experiences on cognitive development.
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BACKGROUND: Worms may protect against allergy. Early-life worm exposure may be critical, but this has not been fully investigated. OBJECTIVES: To investigate whether worms in pregnancy and in early childhood are associated with childhood eczema incidence. METHODS: The Entebbe Mother and Baby Study, an anthelminthic treatment trial, enrolled pregnant women between 2003 and 2005 in Uganda. Mothers were investigated for worms during pregnancy and children annually. Eczema was doctor-diagnosed from birth to age five years. A planned observational analysis was conducted within the trial cohort to investigate associations between worms and eczema. RESULTS: Data for 2345 live-born children were analysed. Hookworm was the most prevalent maternal worm (45%). Childhood worms were less prevalent. Eczema incidence was 4.68/100 person-years. Maternal hookworm was associated with reduced eczema incidence [adjusted hazard ratio (95% confidence interval), p-value: 0.71(0.51-0.99), 0.04] and modified effects of known risk factors for eczema: Dermatophagoides-specific IgE in children was positively associated with eczema incidence if the mother had no hookworm [2.72(1.11-6.63), 0.03], but not if the mother had hookworm [0.41(0.10-1.69), 0.22], interaction p-value = 0.03. Similar interactions were seen for maternal history of eczema {[2.87(1.31-6.27, 0.008) vs. [0.73(0.23-2.30), 0.60], interaction p-value = 0.05}, female gender {[1.82(1.22-2.73), 0.004 vs. [0.96(0.60-1.53), 0.87], interaction p-value = 0.04} and allergen-specific IgE. Childhood Trichuris trichiura and hookworm were inversely associated with eczema. CONCLUSIONS: Maternal hookworm modifies effects of known risk factors for eczema. Mechanisms by which early-life worm exposures influence allergy need investigation. Worms or worm products, and intervention during pregnancy have potential for primary prevention of allergy.
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Eccema/epidemiología , Infecciones por Uncinaria/inmunología , Efectos Tardíos de la Exposición Prenatal/inmunología , Albendazol/uso terapéutico , Antihelmínticos/uso terapéutico , Preescolar , Estudios de Cohortes , Método Doble Ciego , Femenino , Infecciones por Uncinaria/tratamiento farmacológico , Humanos , Incidencia , Lactante , Recién Nacido , Masculino , Embarazo , Modelos de Riesgos Proporcionales , Factores de Riesgo , Uganda/epidemiologíaRESUMEN
BACKGROUND: Helminth infections may modulate immune responses to unrelated pathogens and allergens; these effects may commence prenatally. We addressed the hypothesis that anthelminthic treatment in pregnancy and early childhood would improve responses to immunisation and modulate disease incidence in early childhood with both beneficial and detrimental effects. METHODS AND FINDINGS: A randomised, double-blind, placebo-controlled trial was conducted in Entebbe, Uganda [ISRCTN32849447]. In three independent randomisations, 2507 pregnant women were allocated to receive single-dose albendazole or placebo, and praziquantel or placebo; 2016 of their offspring were randomised to receive quarterly single-dose albendazole or placebo from age 15 months to 5 years. Primary outcomes were post-immunisation recall responses to BCG and tetanus antigens, and incidence of malaria, diarrhoea, and pneumonia; incidence of eczema was an important secondary outcome. Analysis was by intention-to-treat. Of 2345 live births, 1622 (69%) children remained in follow-up at age 5 years. 68% of mothers at enrolment, and 11% of five-year-olds, had helminth infections. Maternal hookworm and Schistosoma mansoni were effectively treated by albendazole and praziquantel, respectively; and childhood hookworm and Ascaris by quarterly albendazole. Incidence rates of malaria, diarrhoea, pneumonia, and eczema were 34, 65, 10 and 5 per 100 py, respectively. Albendazole during pregnancy caused an increased rate of eczema in the children (HR 1.58 (95% CI 1.15-2.17), pâ=â0.005). Quarterly albendazole during childhood was associated with reduced incidence of clinical malaria (HR 0.85 (95% CI 0.73-0.98), pâ=â0.03). There were no consistent effects of the interventions on any other outcome. CONCLUSIONS: Routine use of albendazole in pregnancy may not always be beneficial, even in tropical developing countries. By contrast, regular albendazole treatment in preschool children may have an additional benefit for malaria control where helminths and malaria are co-endemic. Given the low helminth prevalence in our children, the effect of albendazole on malaria is likely to be direct. TRIAL REGISTRATION: Current Controlled Trials ISRCTN32849447.
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Albendazol/uso terapéutico , Antihelmínticos/efectos adversos , Helmintiasis/tratamiento farmacológico , Complicaciones Parasitarias del Embarazo/tratamiento farmacológico , Adulto , Preescolar , Método Doble Ciego , Eccema/epidemiología , Eccema/inmunología , Femenino , Helmintiasis/epidemiología , Helmintiasis/inmunología , Humanos , Incidencia , Lactante , Masculino , Embarazo , Complicaciones Parasitarias del Embarazo/inmunología , Resultado del Tratamiento , Uganda , VacunaciónRESUMEN
We tested the hypothesis that maternal worm infections in pregnancy affect infant motor and neurocognitive development, and that anthelminthic treatment during pregnancy can reverse these effects. We used measures which examine infant motor, cognitive and executive function, including inhibition. We assessed 983 Ugandan infants aged 15 months, using locally appropriate measures within the Entebbe Mother and Baby Study, a trial of anthelminthic treatment during pregnancy. Key exposures were maternal worm infections and anthelminthic treatment during pregnancy. Effects of other health and social factors were controlled for statistically. Of the five major worm species found in the pregnant women, two had influences on the developmental measures: Maternal Mansonella perstans and Strongyloides stercoralis infections showed negative associations with the A-not B-task, and Language, respectively. Performance on other psychomotor and cognitive measures was associated with illnesses during infancy and infants' behavior during assessment, but not with maternal worm infections. There were no positive effects of maternal anthelminthic treatment on infant abilities. Mansonella perstans and Strongyloides stercoralis infection during pregnancy seem associated with impaired early executive function and language, respectively, but single-dose anthelminthic treatment during pregnancy was not beneficial. The biological mechanisms that could underlie these neurocognitive effects are discussed.