Risk factors for atopic and non-atopic asthma in a rural area of Ecuador

Abstract

BackgroundAsthma 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.MethodsA 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.ResultsA 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.ConclusionsThe 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.

Trends in the prevalence of asthma and allergic rhinitis in Italy between 1991 and 2010

“…The prevalence of asthma has significantly increased in non-allergic subjects Due to the strong association of asthma with atopic diseases reported in several studies [31] the role of non-atopic asthma has generally been underestimated [32], even if its prevalence in some countries is similar to [33], or even greater than, that of atopic asthma [34][35][36]. Only few studies have addressed the temporal variation of asthma prevalence in atopic and nonatopic subjects.…”

Community violence and childhood asthma prevalence in peripheral neighborhoods in Salvador, Bahia State, Brazil

“…Maternal schooling and age, children's age and sex, income, housing conditions, overweight in the child, and parents' history of asthma are known to be associated with asthma in the child 1,3,6,21,22,23 . In addition, division of the sample by micro-area could influence the manifestation of community violence, a contextual phenomenon associated with poverty that affects micro-areas differently, such that control of the analyses for this indicator is recommended.…”

“…Many of the factors contributing to asthma symptoms in developed countries appear not to explain a major portion of the prevalence in Latin America 2,3,6 . Importantly, while in the developed countries a high proportion of asthma cases is related to allergy, most cases in Latin America and other developing regions are associated with non-allergic or non-atopic mechanisms, suggesting the need to reassess risk factors for asthma in these contexts 3,6 .…”

“…Importantly, while in the developed countries a high proportion of asthma cases is related to allergy, most cases in Latin America and other developing regions are associated with non-allergic or non-atopic mechanisms, suggesting the need to reassess risk factors for asthma in these contexts 3,6 . Evidence shows that lifestyle factors such as diet and psychosocial aspects 2,7 can contribute to the high asthma prevalence in Latin America.…”

Prevalência de sibilância e fatores associados em crianças menores de 5 anos de Cuiabá, Mato Grosso, Brasil

“…Enquanto em relação à sibilância, houve maior prevalência de sibilantes não atópicos em um centro em desenvolvimento 43 .…”