title: Pulmonary function and incident bronchitis and asthma in children: a community-based prospective cohort study.
abstract: BACKGROUND
  Previous studies revealed that reduction of airway caliber in infancy might increase the risks for wheezing and asthma. However, the evidence for the predictive effects of pulmonary function on respiratory health in children was still inconsistent.
  
  
  METHODS
  We conducted a population-based prospective cohort study among children in 14 Taiwanese communities. There were 3,160 children completed pulmonary function tests in 2007 and follow-up questionnaire in 2009. Poisson regression models were performed to estimate the effect of pulmonary function on the development of bronchitis and asthma.
  
  
  RESULTS
  After adjustment for potential confounders, pulmonary function indices consistently showed protective effects on respiratory diseases in children. The incidence rate ratios of bronchitis and asthma were 0.86 (95% CI 0.79-0.95) and 0.91 (95% CI 0.82-0.99) for forced expiratory volume in 1 second (FEV₁). Similar adverse effects of maximal mid-expiratory flow (MMEF) were also observed on bronchitis (RR = 0.73, 95% CI 0.67-0.81) and asthma (RR = 0.85, 95% CI 0.77-0.93). We found significant decreasing trends in categorized FEV₁ (p for trend = 0.02) and categories of MMEF (p for trend = 0.01) for incident bronchitis. Significant modification effects of traffic-related air pollution were noted for FEV₁ and MMEF on bronchitis and also for MMEF on asthma.
  
  
  CONCLUSIONS
  Children with high pulmonary function would have lower risks on the development of bronchitis and asthma. The protective effect of high pulmonary function would be modified by traffic-related air pollution exposure.
authors.affiliation: Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan. leolee@ntu.edu.tw
authors.forename: Yungling Leo
authors.initials: YL
authors.lastname: Lee
authors.forename: Bing-Fang
authors.initials: BF
authors.lastname: Hwang
authors.forename: Yu-An
authors.initials: YA
authors.lastname: Chen
authors.forename: Jer-Min
authors.initials: JM
authors.lastname: Chen
authors.forename: Yi-Fan
authors.initials: YF
authors.lastname: Wu
mesh_terms: D000293:Adolescent; D001249:Asthma / Q000503:physiopathology*; D001991:Bronchitis / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D011446:Prospective Studies; D012129:Respiratory Function Tests; D013624:Taiwan