Vegetation Fire Smoke, Indigenous Status and Cardio-respiratory Hospital Admissions in Darwin, Australia, 1996-2005
Background: As the frequency and severity of vegetation fires increases around the world, understanding the impacts of the pollution generated from fires is becoming increasingly important. Darwin, Australia, has no important source of air pollution other than seasonal fires in the surrounding savanna that burn for approximately 8 months each year. Our aim was to describe the association between particulate matter less than 10 microns in aerodynamic diameter (PM10) and daily emergency hospital admissions for cardio-respiratory diseases for each fire season (April-November) from 1996 to 2005. We also investigated whether the relationship differed in indigenous Australians, a recognized high risk group.
Methods: Mean daily PM10 was estimated from existing visibility data using a previously validated model. We used overdispersed Poisson generalized linear models with parametric smoothing functions for time and meteorology to examine the association between admissions and PM10 at lags of 0 to 3 days. Interaction terms between indigenous status and PM10 were included to examine the disproportionate impact on indigenous people.
Results: We found positive associations between respiratory disease and PM10 but not with cardiovascular disease. An interaction between same day PM10 and indigenous status for all respiratory admissions, asthma and respiratory infections was identified with greater effects for the PM10 associations in indigenous people than non-indigenous people.
Conclusions: Our results show an association between vegetation fire smoke and daily hospital admissions for respiratory diseases. This relationship was disproportionately higher in indigenous people.