Are high barometric pressure, low humidity and diurnal change of temperature related to the onset of asthmatic symptoms?

Background: Meteorologic factors play a role in the expression of asthmatic symptoms; however, there are controversies about the causal relationship b etween meteorologic factors and asthma. The relationship between meteorolog ic parameters and emergency admissions for asthmatic symptoms in this hospi tal were analyzed. Methods: A total of 205 patients (130 boys and 75 girls, 0.1-16.6 years of age) who were admitted to Hakodate Chuo General Hospital for asthmatic symp toms between 1 January and 31 December 1997 were submitted to our study. We divided a total of 365 days into two groups of days with and without any a dmissions. Meteorologic factors for the days with admissions and 1-3 days b efore hospitalization were compared with those of the days of no admissions . Statistical analysis was done with the Mann-Whitney U-test. Results: On the days with admissions and 1 day before hospitalizations, bar ometric pressure was higher and relative humidity lower than on days with n o admissions. The diurnal difference between maximum and minimum temperatur e for days 1 day before days with admissions was larger than that for 1 day before days with no admissions. Conclusions: It is thought that change in barometric pressure, relative hum idity and temperature had some influence on the worsening of asthmatic symp toms.