Diurnal temperature range and childhood asthma: a time-series study

Background: Hot and cold temperatures have been associated with childhood asthma. However, the relationship between daily temperature variation and childhood asthma is not well understood. This study aimed to examine the relationship between diurnal temperature range (DTR) and childhood asthma. Methods: A Poisson generalized linear model combined with a distributed lag non-linear model was used to examine the relationship between DTR and emergency department admissions for childhood asthma in Brisbane, from January 1st 2003 to December 31st 2009. Results: There was a statistically significant relationship between DTR and childhood asthma. The DTR effect on childhood asthma increased above a DTR of 10 degrees C. The effect of DTR on childhood asthma was the greatest for lag 0-9 days, with a 31% (95% confidence interval: 11% - 58%) increase of emergency department admissions per 5 degrees C increment of DTR. Male children and children aged 5-9 years appeared to be more vulnerable to the DTR effect than others. Conclusions: Large DTR may trigger childhood asthma. Future measures to control and prevent childhood asthma should include taking temperature variability into account. More protective measures should be taken after a day of DTR above 10 degrees C.