Non-atopic more common than atopic asthma in Latin-American children
MedWire News: Results from a study conducted in Ecuador suggest that non-atopic asthma is more common than atopic asthma in Latin-American children.
“Asthma has emerged as an important public health problem of urban populations in Latin America,” explain Ana Lucia Moncayo (Instituto de Saúde Coletiva–Universidade Federal da Bahia, Brazil) and colleagues.
They add: “Epidemiological data suggest that a minority of asthma cases in Latin America may be associated with allergic sensitization, and that other mechanisms causing asthma have been overlooked.”
To investigate, the researchers studied 3960 children, aged 6–16 years, attending schools in 58 rural communities in Ecuador.
Data on wheeze and allergic disease in the children were collected from questionnaires completed by parents and guardians in the presence of the child. The children also underwent skin prick allergy tests and stool samples were analyzed for geohelminth eggs and larvae.
The researchers found that 390 (10.5%) children had suffered from wheeze within the previous 12 months. Of these, 14.4% had atopic wheeze, defined by the presence of at least one positive skin prick test. None of the children with wheeze symptoms were taking regular asthma medications.
The population-attributable fraction for recent wheeze associated with atopy was 2.4%, the team notes in the journal Thorax.
Analysis revealed that major infection with the human whipworm Trichuris trichiura (>490 vs ≤490 eggs per gram) was significantly associated with a reduced risk for atopic wheeze, at an odds ratio [OR] of 0.24, while male gender was associated with a significant increased risk for atopic wheeze, at an OR of 2.73.
Maternal allergic symptoms and a sedentary lifestyle (watching television for more than 3 hours per day) were significantly associated with an increased risk for non-atopic wheeze, at respective ORs of 3.24 and 1.51, while increasing age and birth order were inversely associated with the condition.
Moncayo and team conclude: “The present study shows a predominance of non-atopic compared with atopic wheeze among schoolchildren living in a poor rural tropical region of Latin America.
“Further, there was evidence for different risk factors being associated with the two wheeze phenotypes that may suggest possible different causal mechanisms, and, therefore, has important implications for future preventive strategies.”
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By Mark Cowen