Asma e rinite alérgica em área rural endêmica para esquistossomose

Abstract

Asthma and allergic diseases are chronic pathologies with an expressive growth in itsprevalence in recent decades. However, some studies have demonstrated that in rural areasthey are less frequent. The factors associated with lower prevalence in these areas are notalready fully understood, but helminth infections, presence of large families and the povertyare believed to have a protective effect on the development of these diseases. This studyaimed to examine the factors associated with the asthma and allergic rhinitis in 346 childrenand adolescents of a rural area, endemic for schistossomiasis, in the Jequitinhonha Valley,Minas Gerais. The presence of Schistosoma mansoni infection was evaluated by Kato-Katzmethod. The standard questionnaire of the International Study of Asthma and Allergies inChildhood (ISAAC) was applied to determine the prevalence of asthma and allergic rhinitissymptoms. Demographic and socioeconomic data as well as the environmental exposure toinfectious agents and allergenic were obtained of complementary questionnaires. The weightand height were evaluated in 294 children and adolescents to determine the nutritionalstatus. The prevalence of asthma evaluated by reports of wheeze in the last year was 12.7%and a percentage of 8.7% of the participants related medical diagnosis of asthma. Thesymptoms of allergic rhinitis in the last 12 months were reported by 12.4% and only 3.2%reported medical diagnosis of rhinitis. There was an association between allergic rhinitis andasthma in 4.9% of children and adolescents. The schistossomiasis was highly prevalent inthe region with 57.2% of children and adolescents affected by this infection. The risk factorsrelated with asthma were having an allergic mother (OR = 2.82; CI 95%: 1.01 - 5.43), havingallergic rhinitis in the last 12 months (OR = 7.18; CI 95%: 2.88 - 17.82), being overweight orobese (OR = 4.37; CI 95%: 1.40 - 13.63). The asthma was also more frequent in thechildren and adolescents that lived in the houses that had bathroom (OR = 3.71; CI 95%:1.21 11.38). The use of stream water was related to a lower risk of asthma (OR = 0.43; CI95%: 0.19 - 0.96). In relation to allergic rhinitis, the presence of eczema (OR = 6.74; CI 95%:1.77 - 25.58) and asthma (OR = 8.61; CI 95%: 3.49 - 21.22) symptoms in the last 12 months,being overweight or obese (OR = 3.11; CI 95%: 1.13 - 8.57) and having contact withchickens outside the house (OR = 2.51; CI 95%: 1.11 - 5.69) were associated with the riskfor this disease. The family income between 1.1 and 2.0 minimum wages (OR = 0.30; CI95%: 0.09 - 0.92), and up to 1.0 minimum wage (OR = 0.28; IC 95%: 0.10 - 0.84) wasassociated with a lower risk of allergic rhinitis. Although no relationship was observedbetween infection with S. mansoni and the presence of asthma and allergic rhinitissymptoms, lower prevalence of these diseases were found among individuals infected andwith high intensity of infection. It suggests the importance of developing new studies in thefuture that compare the gradients of prevalence of the asthma and allergic rhinitis in urbanand rural areas and that combine evaluations clinical, epidemiological and immunological fora better understanding of determinants factors for these diseases.