title: Effects of traffic air pollution and hornbeam pollen on adult asthma hospitalizations in Zagreb.
abstract: BACKGROUND
  Environmental factors play an important role in asthma morbidity, although the contribution of individual pollutants or pollens in exacerbating asthma is not completely elucidated. Despite the evidence of importance of the hornbeam pollen in inducing allergic sensitization, its role in provoking asthma exacerbation has not been evaluated. The aim of the present study was to investigate effects of traffic pollutants on adult asthma hospitalization adjusting for pollens including hornbeam.
  
  
  METHODS
  During a 3-year period, health and environmental data were collected and analyzed. Daily asthma hospitalizations were regressed on pollutants and potential confounding variables using an autoregressive Poisson model.
  
  
  RESULTS
  The risk of asthma hospitalization was associated significantly with the 95th to 99th percentile increase in levels of nitrogen dioxide (RR = 1.22; 95% CI: 1.05-1.40), carbon monoxide (RR = 1.25; 95% CI: 1.01-1.55) and hornbeam pollen (RR = 1.21; 95% CI: 1.11-1.30). The effect of nitrogen dioxide was delayed by 5 days. No statistically significant increase in the risk of asthma hospitalization was found for PM(10) particles. A comparison among the standardized regression coefficients and their respective p values indicates that the most important risk factor for asthma hospitalization is associated with hornbeam pollen levels. No statistically significant interactions between pollutants and pollens were detected.
  
  
  CONCLUSIONS
  The current results suggest that traffic-related air pollution is associated with increased risk of adult asthma hospitalization. Nonetheless, the most significant risk for asthma hospitalization is associated with hornbeam pollen levels in the city of Zagreb.
authors: University Hospital Centre Zagreb, Clinic for Lung Diseases Jordanovac, University of Zagreb School of Medicine, Zagreb, Croatia. krmpotic @ vip.hr
authors: Diana
authors: D
authors: Krmpotic
authors: Vesna
authors: V
authors: Luzar-Stiffler
authors: Neven
authors: N
authors: Rakusic
authors: Asja
authors: A
authors: Stipic Markovic
authors: Ivana
authors: I
authors: Hrga
authors: Mladen
authors: M
authors: Pavlovic
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects / Q000276:immunology; D000397:Air Pollution / Q000009:adverse effects*; D001249:Asthma / Q000209:etiology / Q000503:physiopathology*; D029401:Betulaceae / Q000009:adverse effects* / Q000276:immunology; D017523:Croatia; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D018986:Motor Vehicles; D009585:Nitrogen Dioxide / Q000009:adverse effects; D016012:Poisson Distribution; D011058:Pollen / Q000009:adverse effects*; D013458:Sulfur Dioxide / Q000009:adverse effects
chemical_list: D000393:Air Pollutants; D013458:Sulfur Dioxide; D009585:Nitrogen Dioxide