Study of relationship between climatic variables and incidence of asthma attacks leading to hospitalization in the children's hospital of Khorramabad city

Asthma is one of the commonest chronic childhood diseases and one of the main factors of hospital admission at these ages. The main causes of increasing death due to asthma are inability in the diagnosis and piddling the severity of the diseases، delay in the recourse and inappropriate treatment. Therefore the early diagnosis of children at risk for urgent admission in special care unit and also identifying environmental factors of incidence and intensification of this disease play an important role in its management. In this study the relationship between climatic variables (temperature، evaporation، relative humidity، sunny hours، wind direction and speed، number of days with frost)، and number of asthma attacks leading admission of children in Ayatollah Madani hospital (The only children''s hospital) in Khorramabad city was studied. In order to identify the climatic variables that are effective in the incidence of children asthma attacks، multiple regression statistical stepwise method has been used. In this method، 10 climatic independent variables with a dependent variable of children asthma attacks during a 9-year period from 2007 to 2009 were studied، and three climatic variables have been known in three steps. In the first Step، monthly average of sunny hours variable (with coefficient of correlation 37. 15%) and the amount of p=0. 058 was entered into the model and the variable accuracy was confirmed. In the second step the absolute minimum temperature variable (with coefficient of correlation 31. 5%) and assumption of being fixed first variable as compared with dependent variable entered to regression model، and in the third step، number of days with frost variable (with coefficient of correlation 9. 5%) was entered into the model and the multiple correlation coefficients (78. 15%) was yield. The results have indicated that among the climatic variables، monthly average of sunny hours variable with inverse correlation، the minimum absolute temperature and average monthly number of days frost with direct correlation have the most correlation with children asthma attacks. Comparison of the results of this study with other researches illustrates that effective variables in thermal environmental conditions such as the absolute minimum temperature and frost days have good correlation with asthma attacks. But considerable point is the types of variables that in the past researches between sunny hours and number of days with frost، and the mentioned disease no relationship has been shown.