Risk factors affecting asthma prevalence in adolescents living in Istanbul, Turkey.

BACKGROUND Asthma is one of the most important diseases of childhood. The aim of this study was to evaluate the prevalence of asthma symptoms and risk factors affecting asthma. METHODS In a cross-sectional study design, 9991 children, aged 13-14 years in 61 primary schools in 32 districts of Istanbul were evaluated. Asthma prevalence among the children was assessed using the ISAAC protocol. RESULTS In our study, a total of 10,894 questionnaires were distributed to 13-14 years old children, and of these 9991 questionnaires were suitable for analysis with an overall response rate of 91.7%. The rates of wheeze ever, wheezing in last 12 months and lifetime doctor diagnosed asthma prevalence were 17.4%, 9.0%, and 11.8%, respectively. There were 4746 boys (47.9%) and 5166 girls (52.1%) with M/F ratio of 0.92. Atopic family history, fewer than three siblings living at home, tonsillectomy or adenoidectomy history, consumption of fermented foods, mixed pickles, margarine and meat were found to be associated with an increased asthma risk. Use of paracetamol in the last 12 months, consumption of fruit and animal fats acted as a protective factor against asthma. The Mediterranean-style diet was not associated with the prevalence of asthma. CONCLUSIONS Lifetime doctor diagnosed asthma prevalence was found to be 11.8% in 13-14 year olds. History of tonsillectomy and/or adenoidectomy and consumption of fermented foods, mixed pickles, margarine and meat may increase the symptoms of asthma. Usage of paracetamol and consumption of animal fats may be investigated as a protective factor against asthma.