Prevalence of Rhinitis and Associated Factors in Schoolchildren who Live in the Amazon Islands

Background The prevalence of rhinitis has been reported to be higher in urban areas. Objective To determine the prevalence of rhinitis in schoolchildren who lived on two islands in the Brazilian Amazon, including a rural island and an urban island, and to identify the associated risk factors. Methods Four hundred children (200 per island) were evaluated by using the International Study of Asthma and Allergy in Childhood standard written questionnaire (rhinitis module). A convenience sample for both islands was selected based on the age group of the study (5-8 years). The children were assessed for potential risk factors (complementary written questionnaire) identified by logistic regression. Results The prevalence of active rhinitis was significantly higher in the children who lived on Outeiro Island compared with Combú Island (34.5% versus 18.0%, respectively). The associated risk factors for rhinitis symptoms on Combú Island included parental history of rhinitis (odds ratio [OR] 9.4 [95% confidence interval {(CI}, 2.1-41.4]) and delivery by caesarean-section (OR 5.2 [95% CI, 1.2-21.9]), and for Outeiro Island included parental history of rhinitis (OR 4.5 [95% CI, 1.7-11.2]) and of asthma (OR 3.8 [95% CI, 1.5-9.8]), nocturnal cough in the previous year (OR 5.8 [95% CI, 2.1-16.0]), breast-feeding (≥6 months) (OR 9.6 [95% CI, 1.1-82.1]), moisture (OR 2.4 [95% CI, 0.9-6.4]), and consumption of fruit juice more than two times a week (OR 4.3 [95% CI, 1.2-15.0]). Conclusion The different risk factors identified for rhinitis on each island indicated the role of the urban environment in the development of the disease.