Factors associated with asthma in adolescents in the city of Fortaleza, Brazil.

Objective: Asthma is a chronic inflammatory airway disease. In Brazil, little is known about factors associated with this disease. This study aimed to identify factors associated with asthma in 13- to 14-year-old adolescents in Fortaleza, Ceará, Brazil.

Methods: It is a cross-sectional population-based study, with a probability sample of 3015 students in 2006-2007. We used the questionnaires about asthma, rhinitis and socio-demographic/environmental factors from the International Study for Asthma and Allergies in Childhood (ISAAC) protocol. Current asthma was defined as physician-diagnosed asthma and wheezing in the previous 12 months. Bivariate analysis was performed between asthma and factors included in the study, using prevalence ratio and Chi-square test. Confidence intervals (95%) and odds ratio (OR) were also calculated. Factors associated with asthma in bivariate analysis were then assessed using logistic regression.

Results: Final sample was composed by 694 adolescents, 179 with asthma. Rhinoconjunctivitis and consumption of stuffed biscuits and fried snacks three or more times per week were independently and positively associated with asthma; consumption of fruits three or more times per week was negatively associated with asthma.

Conclusions: Dietary factors were the most associated with asthma in this study. Besides rhinoconjunctivitis, consumption of stuffed biscuits and fried snacks (foods with high content of saturated fat) three or more times per week were independently associated with asthma as aggravating factors, while the consumption of fruits three or more times per week was associated with asthma as protective factor. Interventions acting on these factors may decrease the occurrence of asthma in this population.