Air pollution and asthma-related hospitalizations in the Malopolska region

Introduction: Asthma is one of the most frequent chronic disease worldwide. Its prevalence has grown rapidly over last years, however the differences between countries are significant. Aim: The purpose of this study was to assess the relation between the number of urgent asthma-related hospital admissions and air pollution in the Malopolska region. Material and methods: We used data collected in the frame of the project “Hospitalization” – the Polish Survey on Overall Hospital Morbidity in Poland. We analyzed hospital records for Malopolska region with primary cause of hospital admission defined as bronchial asthma or status asthmaticus (code J45.* or J46 according to ICD-10) for years 2005–2009. Air pollution data were collected from monitoring station in Malopolska. Poisson regression model was used to assess the impact of air pollution level on number of hospital admissions with adjustment for the daily mean of temperature. Results: During the years 2005–2009 overall 6942 urgent asthma-related hospital admissions were observed. The level of air pollution during this period was high, for example, mean daily PM10 air pollution level was higher than 50 µg/m3 for more than 30% of days in most monitoring settings. The highest PM10 level was observed to be more than 350 µg/m3. Out of the analyzed pollutant the most important predictor was found to be SO2 with RR41,039 (95%CI: 1,014–1,064) and PM10 with RR41,018 (95%CI: 1.008–1.029) for 10 µg/m3 increase of pollutant. We have also examined the effect of air pollution during the previous days on asthma hospitalizations. The effect of air pollution by sulfur dioxide on number of hospital admissions from asthma was also observed with RR41,051 (95%CI: 1,028–1,075) and by PM10 with RR41,016 (95%CI: 1,007–1,025) for a seven days delay. In our study we have also observed the relation between air pollution by NO2 in previous days and asthma-related hospital admissions. Conclusions: The number of asthma hospitalizations, especially those unplanned, probably because of exacerbation of asthma episodes can be reduced by lowering air pollution level