Genetic variants in 17q12-21 locus and childhood asthma in Brazil: Interaction with Varicella zoster virus seropositivity.

BACKGROUND: Asthma is a complex disease with worldwide public health relevance, is related to environmental causes and a genetic predisposition. The chromosomal 17q12-21 locus has been consistently demonstrated to be associated with asthma risk. The effects of variants in the 17q12-21 locus on childhood asthma were first identified in a genome wide- association study. Since that time, those findings have been replicated in different populations but not in South American populations. OBJECTIVE: This study aimed to investigate the role of variants in the 17q12-21 locus on asthma in a sample of Brazilian children. METHODS: This was a cross-sectional study conducted on a cohort of 1247 children. These analyses used 50 Single Nucleotide Variants (SNVs) in the 17q12-21 locus were genotyped as part of a genome wide association study (GWAS). RESULTS: Four SNVs (rs4065275, rs12603332, rs73985228 and rs77777702) were associated with childhood asthma. The rs73985228 exhibited the strongest association across the different genetic models (OR, 95%CI 2.8, 1.44-3.21, p < 0.01). In an analysis that was stratified by atopy, two SNVs (rs73985228 and rs2715555) were found to be associated with atopic and non-atopic asthma. For the first time, we observed a significant interaction with seropositivity for the Varicella zoster virus (for rs4065275, p = 0.02, and for rs12603332, p = 0.04); i.e., the association was found in those who were seropositive but not in those who were seronegative for this virus. CONCLUSIONS: We confirmed the associations of variants in the 17q12-21 locus with atopic and non-atopic asthma and identified an interaction with seropositivity for the Varicella zoster virus.

Symptoms of asthma and associated factors in adolescents from Salvador, Bahia. / Sintomas de asma e fatores associados em adolescentes de Salvador, Bahia.

OBJECTIVE: Identify the factors associated with asthma symptoms in adolescents. METHODS: Cross-sectional study with the participation of 1,176 students between the ages of 11 and 17 years old, in Salvador, Bahia, Brazil. The asthma symptoms were identified by using the standardized questionnaire from The International Study of Asthma and Allergies in Childhood Program (ISAAC), phase III. The subjects' food intake data were collected by a semiquantitative food frequency questionnaire (FFQ) comprised of 97 food items. All of the information was collected during a single interview. Anthropometric, socioeconomic, and demographic data were collected from the study population. The robust Poisson model was adopted to obtain the raw and adjusted PR (prevalence ratio). RESULTS: From the total number of adolescents, 57.6% are female and 83.71% of them were between 13 and 17 years old. The prevalence of asthma symptoms was of 7.6%, being higher among males (9.62%). The prevalence of wheezing in the last 12 months was 8.6%. Among the adolescents with rhinitis and eczema, the prevalence of asthma symptoms was of 15.2 and 14.3%, respectively. After an adjusted analysis, the following factors were identified: females PR = 0.64 (95%CI 0.42 - 0.96), rhinitis PR = 3.23 (95%CI 2.17 - 4.83) and the 2nd tertile of the healthy pattern (moderate consumption) PR = 0.61 (95%CI 0.37 - 0.99). CONCLUSION: Rhinitis and eczema were presented as risk factors for asthma symptoms. The healthy food intake pattern that had been stratified in tertiles, presented the 2nd tertile as a protector for asthma symptoms.

Sintomas de asma e fatores associados em adolescentes de Salvador, Bahia / Symptoms of asthma and associated factors in adolescents from Salvador, Bahia

RESUMO: Objetivo: Identificar os fatores associados a sintomas de asma em adolescentes. Métodos: Estudo transversal, com a participação de 1.176 alunos com idade entre 11 e 17 anos, em Salvador, Bahia, Brasil. Os sintomas de asma foram identificados utilizando-se o questionário padronizado do The International Study of Asthma and Allergies in Childhood Program (ISAAC), fase III. A avaliação do consumo alimentar dos adolescentes foi obtida por meio de questionário da frequência alimentar (QFA) semiquantitativo, com 97 itens alimentares, sendo as informações coletadas em uma única entrevista com os estudantes. Foram coletados dados antropométricos, socioeconômicos e demográficos da população do estudo. O modelo de Poisson robusto foi adotado para obtenção da razão de prevalência (RP) bruta e ajustada. Resultados: Do total de adolescentes, 57,6% são do sexo feminino e 83,7% tinham de 13 a 17 anos de idade. A prevalência de sintomas de asma encontrada foi de 7,6%, sendo mais elevada no sexo masculino (9,62%). A prevalência de chiado nos últimos 12 meses foi de 8,6%. Entre os adolescentes que tinham rinite e eczema a prevalência de sintomas de asma foi de 15,2 e 14,3% respectivamente. Após análise ajustada, os seguintes fatores se associaram à asma: sexo feminino RP = 0,64 (IC95% 0,42 - 0,96), rinite RP = 3,23 (IC95% 2,17 - 4,83) e o 2o tercil do padrão saudável (consumo moderado) RP = 0,61 (IC95% 0,37 - 0,99). Conclusão: Rinite e eczema apresentaram-se como fatores de risco para sintomas de asma. O padrão alimentar saudável estratificado em tercil apresentou o segundo tercil como protetor para sintomas de asma.

ABSTRACT: Objective: Identify the factors associated with asthma symptoms in adolescents. Methods: Cross-sectional study with the participation of 1,176 students between the ages of 11 and 17 years old, in Salvador, Bahia, Brazil. The asthma symptoms were identified by using the standardized questionnaire from The International Study of Asthma and Allergies in Childhood Program (ISAAC), phase III. The subjects' food intake data were collected by a semiquantitative food frequency questionnaire (FFQ) comprised of 97 food items. All of the information was collected during a single interview. Anthropometric, socioeconomic, and demographic data were collected from the study population. The robust Poisson model was adopted to obtain the raw and adjusted PR (prevalence ratio). Results: From the total number of adolescents, 57.6% are female and 83.71% of them were between 13 and 17 years old. The prevalence of asthma symptoms was of 7.6%, being higher among males (9.62%). The prevalence of wheezing in the last 12 months was 8.6%. Among the adolescents with rhinitis and eczema, the prevalence of asthma symptoms was of 15.2 and 14.3%, respectively. After an adjusted analysis, the following factors were identified: females PR = 0.64 (95%CI 0.42 - 0.96), rhinitis PR = 3.23 (95%CI 2.17 - 4.83) and the 2nd tertile of the healthy pattern (moderate consumption) PR = 0.61 (95%CI 0.37 - 0.99). Conclusion: Rhinitis and eczema were presented as risk factors for asthma symptoms. The healthy food intake pattern that had been stratified in tertiles, presented the 2nd tertile as a protector for asthma symptoms.