Jornal de Pediatria (Dec 2001)
Fatores de risco, aspectos clínicos e laboratoriais da asma em crianças Risk factors, clinical and laboratory aspects of asthma in children
Abstract
OBJETIVO: avaliar os aspectos clínicos, laboratoriais, e os fatores de risco associados à asma em crianças atendidas no Ambulatório de Pediatria, do Hospital Universitário Júlio Müller. Método: estudo de caso-controle, incluindo 59 crianças asmáticas (casos) e 104 não-asmáticas (controles). Os seguintes fatores foram considerados para análise de risco: escolaridade dos pais, exposição aos alérgenos domiciliares, tabagismo passivo, aleitamento materno, renda e antecedentes familiares alérgicos. Foram coletadas amostras de sangue para hemograma e dosagem de IgE total e específica para alérgenos. Realizou-se teste cutâneo de hipersensibilidade imediata pelo método de puntura para os seguintes alérgenos: ácaros, animais, fungos e baratas com controles positivo (histamina) e negativo (solução fisiológica).Um modelo de regressão logística foi usado para calcular odds ratio (OR) e intervalo de confiança (IC) 95% ajustado para outros fatores de risco e confundidores. RESULTADOS: dentre os fatores de risco estudados, sexo, baixa escolaridade, baixa renda, tempo de aleitamento materno e tabagismo passivo não estiveram associados à ocorrência de asma. A exposição aos alérgenos foi semelhante nos dois grupos, a não ser pela maior freqüência de animais nos domicílios dos controles (c²=16,9; P OBJECTIVE: to evaluate the clinical and laboratory aspects and the risk factors associated with asthma in children treated at the Pediatric Outpatient Clinic of Hospital Universitário Júlio Müller. METHODS: A case-control study including 59 asthmatic children (cases) and 104 nonasthmatic children (controls). The following factors were considered for risk analysis: parents' level of education, domestic exposure to allergens, passive smoking, breast feeding, low income, and family history of allergy. Samples of blood were collected for hemogram and to determine the total serum IgE as well as the one specific to allergens. Immediate hypersensitivity skin tests were performed with puncture for the detection of the following allergens: house dust mite, animals, molds, and cockroaches with positive (histamine) and negative controls (physiologic solution). A logistic regression model was used to calculate the odds ratio (OR) and 95% confidence intervals (95%CI) adjusted for risk factors and for confounding factors. RESULTS: Among the risk factors studied, sex, parents' low level of education, low income, length of the breast feeding period, and passive smoking were not associated with the presence of asthma. The domestic exposure to allergens was similar in both groups except for the higher frequency of pets at the homes of control patients (c²=16.9; P < 0.05). Paternal history of rhinitis was the only association with asthma (OR=3.33; 95%CI: 1.03-11.17; P < 0.05). The asthmatic children presented higher frequency of positive reactions to skin tests than the controls, mainly to house dust mites: Dermatophagoides pteronyssinus (69.5%), Dermatophagoides farinae (59.3%) and Blomia tropicalis (59.3%); cockroaches: Periplaneta americana (59.3%), and cat: Felis domesticus (37.3%), with OR between 11.2-21.0; P < 0.05. Eosinophilia and serum levels of total IgE were more elevated in the group of asthmatic children (P < 0.05). The positivity of the specific IgE test for Dermatophagoides pteronyssinus and Blomia tropicalis was higher in the cases than in the controls (P < 0.05). The multivariate analysis showed that sensitization to the allergens produced by cockroaches (OR=9.26; 95%CI: 2.59-33.4), animals (OR=3.93; 95%CI: 1.05-14.67) and house dust mites (OR=3.74; 95%CI: 1.18-11.8) were the most important risk factors for asthma. CONCLUSIONS: The sensitization to indoor allergens, mainly to house dust mites, cockroaches, and cats showed a strong association with asthma in this study.
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