Allergen sensitization of asthmatic and nonasthmatic schoolchildren in Costa Rica

Abstract

The prevalence of asthma among schoolchildren in Costa Rica is very high -- at the level of 20-30% -- and the reason is still unknown. A group of children from our previous epidemiologic study was randomly selected in order to establish the relation between asthma symptoms and allergy sensitization to common allergens. Serum samples from children with and without asthma were analyzed for the presence of IgE antibodies to 36 different allergens, for the presence of IgE antibodies to a pool of 10 common allergens, and for total serum IgE. The most prevalent IgE antibodies were those to mite, cockroach, dog, and house-dust allergens with MAST pipettes for the serologic measurements. Positive reactions to house dust, mite, cat, and the two molds (Alternaria and Cladosporium), and food allergens such as egg white, peanut, and shellfish were significantly more prevalent among the asthmatics than the nonasthmatics. Sensitization was equally prevalent at different ages, but the house-dust, mite, cat, dog, cockroach, Alternaria, and egg-white allergens had sensitized boys more often than girls (P < 0.01). The result of the analysis of IgE antibodies to a pool of 10 common allergens by Phadiatop supported the MAST pipette results, showing allergen sensitization in 57.7% of the asthmatic children and 42.3% in the nonasthmatic group. The concentration of IgE was significantly higher among the asthmatic children (372.2 kU/l) than among the nonasthmatic children (249.1 kU/l) (P < 0.00001). Parasitic infestations were not examined in this study, but in most of Costa Rica these have largely been eliminated and could not explain the high total IgE levels. Our data indicate that the very high prevalence of bronchial asthma in Costa Rican schoolchildren can be related to sensitization, especially to airborne indoor allergens such as those of mites, cockroaches, and dogs.

Fatores de risco, aspectos clínicos e laboratoriais da asma em crianças

“…Na infância, além das doenças alérgicas, as parasitoses intestinais podem elevar esses níveis, entretanto a freqüência de parasitas que fazem ciclo pulmonar foi de 16,3% nos casos e 17% nos controles. Portanto, na análise dos resultados, a diferença estatística no nível sérico de eosinófilos e de IgE total provavelmente deve estar mais relacionada com a sensibilização alérgica do que com a presença de parasitoses, o que está de acordo com outros estudos 33,34 . A análise multivariada mostrou que a sensibilização aos alérgenos de baratas, animais e ácaros manteve-se como importante fator de risco, o que vai ao encontro de outros estudos epidemiológicos 12,13 .…”

“…Idade (meses) média (dp ‡ ) 99,2 (34,8) Para a análise multivariada através de regressão logísti-ca, um modelo foi criado apenas com os fatores que mantinham relação estatística com presença de asma na análise univariada e no modelo final, sensibilização às baratas, a animais e a ácaros manteve-se como fator de risco importante após ajuste por sexo e faixa etária. O OR para rinite paterna após ajuste não mostrou associação estatística.…”

Asthma and Sensitization Pattern in Children

“…Nowadays we have a wide overview of demographic distribution of sensitizations and its correlation to asthma. As one could expect, "residence of rural area is associated with a significant lower prevalence of allergic sensitization" seen in more than 400 school children 12-16 years old (Majkowska-Wojciechowska et al, 2007) and boys are significantly more often than girls sensitized to a wide range of allergens (Soto-Quiros et al, 1998) as they are more often affected by asthma. However, in Italy, polysensitization of children living in a rural area especially against pollen and mould led to comparable asthma prevalence as house dust mite sensitization in those living in urban regions (Verini et al, 2005).…”

Sensibilisierungsstatus bei Kindern und Jugendlichen mit Heuschnupfen und anderen atopischen Erkrankungen

“…Jungen sind häufiger sensibilisiert als Mädchen [4], und in vielen Studien finden sich bei Jungen auch größere Heuschnupfenprävalenzen, jedoch ist die Datenlage hier nicht einheitlich [15].…”

“…Die Sensibilisierungsraten zeigen Unterschiede aber auch abhän-gig vom Geschlecht [4], von der familiä-ren Vorbelastung (das heißt abhängig von genetischen Faktoren), der Häufigkeit einer Haustierhaltung [5], vom sozialen Status [6] und von anderen Merkmalen. Es scheint sich dabei abzuzeichnen, dass Umgebungseinflüsse für die Ausprägung von Sensibilisierungen eine größere Rolle spielen könnten als genetische Merkmale.…”