Obesity and the occurrence of bronchitis in adolescents

Objective: Previous studies have shown that an elevated BMI was associated with higher risks of bronchitis among children. The magnitude of how increase in BMI influencing the risk of incident bronchitis remained unexplored. The objective of this study is to assess the association between BMI and the incidence of bronchitis in the Taiwan Children Health Study. Design: A school-based prospective cohort study. Methods: We conducted a population-based prospective cohort study among seventh-grade school children in 14 Taiwanese communities. A total of 3,634 adolescents completed follow-up questionnaire in 2009. Associations between BMI and incident bronchitis were analyzed by multiple Poisson regression models, taking overdispersion into account. Results: Among eligible cohort participants without bronchitis at study entry, the proportion of overweight and obesity were 32.1% and 17.9%. Overweight was 40.7% and obesity was 27.7% among those with incident bronchitis. The BMI percentile categories showed significant increasing trends for bronchitis in total eligible children and in girls (P for trend <0.001). Overweight and obesity were both associated with increased risks of incident bronchitis. This association was significant in girls only while stratified by gender. Conclusions: Our data showed that the BMI percentile and weight status were associated with higher risks of incident bronchitis in adolescents, especially in girls.