Risk factors for atopic and non-atopic asthma in a rural area of Ecuador
OPEN ACCESS- Ana Lucia Moncayo1,
- Maritza Vaca2,
- Gisela Oviedo2,
- Silvia Erazo2,
- Isabel Quinzo2,
- Rosemeire L Fiaccone3,
- Martha E Chico2,
- Mauricio L Barreto1,
- Philip J Cooper4
- 1Instituto de Saúde Coletiva, Universidade Federal da Bahia, Salvador, Bahia, Brazil
- 2Instituto de Microbiologia, Universidad San Francisco de Quito, Quito, Ecuador
- 3Instituto de Matemática, Universidade Federal da Bahia, Salvador, Bahia, Brazil
- 4Centre for Infection, St George's University of London, Tooting, London, UK
- Correspondence to Miss Ana Lucia Moncayo, Instituto de Saúde Coletiva–Universidade Federal da Bahia, Rua Basílio da Gama, s/n, Salvador, Bahia, CEP: 40.110-040 Brazil; almoncayo{at}hotmail.com
- Received 2 September 2009
- Accepted 17 January 2010
Abstract
Background Asthma has emerged as an important public health problem of urban populations in Latin America. Epidemiological data suggest that a minority of asthma cases in Latin America may be associated with allergic sensitisation and that other mechanisms causing asthma have been overlooked. The aim of the present study was to investigate risk factors for atopic and non-atopic asthma in school-age children.
Methods A cross-sectional study was conducted among 3960 children aged 6–16 years living in Afro-Ecuadorian rural communities in Esmeraldas province in Ecuador. Allergic diseases and risk factors were assessed by questionnaire and allergic sensitisation by allergen skin prick reactivity.
Results A total of 390 (10.5%) children had wheeze within the previous 12 months, of whom 14.4% had at least one positive skin test. The population-attributable fraction for recent wheeze associated with atopy was 2.4%. Heavy Trichuris trichiura infections were strongly inversely associated with atopic wheeze. Non-atopic wheeze was positively associated with maternal allergic symptoms and sedentarism (watching television (>3 h/day)) but inversely associated with age and birth order.
Conclusions The present study showed a predominance of non-atopic compared with atopic wheeze among schoolchildren living in a poor rural region of tropical Latin America. Distinct risk factors were associated with the two wheeze phenotypes and may indicate different causal mechanisms. Future preventive strategies in such populations may need to be targeted at the causes of non-atopic wheeze.
Footnotes
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Funding Wellcome Trust, UK, HCPC Latin American Centres of Excellence Programme (ref 072405/Z/03/Z). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.
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Competing interests None.
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Ethics approval This study was conducted with the approval of the ethics committee of the Hospital Pedro Vicente Maldonado, Ecuador.
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Provenance and peer review Not commissioned; externally peer reviewed.
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