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Vegetation fire smoke, indigenous status and cardio respiratory hospital admissions in Darwin, Australia, 1996-2005

Citation

Hanigan, IC and Johnston, F and Morgan, GG, Vegetation fire smoke, indigenous status and cardio respiratory hospital admissions in Darwin, Australia, 1996-2005, Environmental Health, 7, (Aug 5) pp. 42. ISSN 1832-3367 (2008) [Refereed Article]

DOI: doi:10.1186/1476-069X-7-42

Abstract

Background: Air pollution in Darwin, Northern Australia, is dominated by smoke from seasonal fires in the surrounding savanna that burn during the dry season from April to November. Our aim was to study the association between particulate matter less than or equal to 10 microns diameter (PM10) and daily emergency hospital admissions for cardio-respiratory diseases for each fire season from 1996 to 2005. We also investigated whether the relationship differed in indigenous Australians; a disadvantaged population sub-group. Methods: Daily PM10 exposure levels were estimated for the population of the city from visibility data using a previously validated model. We used over-dispersed Poisson generalized linear models with parametric smoothing functions for time and meteorology to examine the association between admissions and PM10 up to three days prior. An interaction between indigenous status and PM10 was included to examine differences in the impact on indigenous people. Results: We found both positive and negative associations and our estimates had wide confidence intervals. There were generally positive associations between respiratory disease and PM10 but not with cardiovascular disease. An increase of 10 ėg/m3 in same-day estimated ambient PM10 was associated with a 4.81% (95%CI: -1.04%, 11.01%) increase in total respiratory admissions. When the interaction between indigenous status and PM10 was assessed a statistically different association was found between PM10 and admissions three days later for respiratory infections of indigenous people (15.02%; 95%CI: 3.73%, 27.54%) than for non-indigenous people (0.67%; 95%CI: -7.55%, 9.61%). There were generally negative estimates for cardiovascular conditions. For nonindigenous admissions the estimated association with total cardiovascular admissions for same day ambient PM10 and admissions was -3.43% (95%CI: -9.00%, 2.49%) and the estimate for indigenous admissions was -3.78% (95%CI: -13.4%, 6.91%), although ambient PM10 did have positive (non-significant) associations with cardiovascular admissions of indigenous people two and three days later. Conclusion: We observed positive associations between vegetation fire smoke and daily hospital admissions for respiratory diseases that were stronger in indigenous people. While this study was limited by the use of estimated rather than measured exposure data, the results are consistent with the currently small evidence base concerning this source of air pollution.

Item Details

Item Type:Refereed Article
Research Division:Medical and Health Sciences
Research Group:Public Health and Health Services
Research Field:Environmental and Occupational Health and Safety
Objective Division:Health
Objective Group:Public Health (excl. Specific Population Health)
Objective Field:Environmental Health
UTAS Author:Johnston, F (Associate Professor Fay Johnston)
ID Code:52816
Year Published:2008
Web of Science® Times Cited:37
Deposited By:Menzies Institute for Medical Research
Deposited On:2008-09-19
Last Modified:2009-04-25
Downloads:0

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