Ambient biomass smoke and cardio-respiratory hospital admissions in Darwin, Australia
Fay H Johnston1, Ross S Bailie, Louis S Pilotto
1Menzies School of Health Research, Charles Darwin University, Darwin, Australia. fay.johnston@utas.edu.au
Background:
Increasing severe vegetation fires worldwide has been attributed to both global environmental change and land management practices. However there is little evidence concerning the population health effects of outdoor air pollution derived from biomass fires. Frequent seasonal bushfires near Darwin, Australia provide an opportunity to examine this issue. We examined the relationship between atmospheric particle loadings <10 microns in diameter (PM10), and emergency hospital admissions for cardio-respiratory conditions over the three fire seasons of 2000, 2004 and 2005. In addition we examined the differential impacts on Indigenous Australians, a high risk population subgroup.
Methods:
We conducted a case-crossover analysis of emergency hospital admissions with principal ICD10 diagnosis codes J00-J99 and I00-I99. Conditional logistic regression models were used to calculate odds ratios for admission with 10 microg/m3 rises in PM10. These were adjusted for weekly influenza rates, same day mean temperature and humidity, the mean temperature and humidity of the previous three days, days with rainfall > 5 mm, public holidays and holiday periods.
Results:
PM10 ranged from 6.4 - 70.0 microg/m3 (mean 19.1). 2466 admissions were examined of which 23% were for Indigenous people. There was a positive relationship between PM10 and admissions for all respiratory conditions (OR 1.08 95%CI 0.98-1.18) with a larger magnitude in the Indigenous subpopulation (OR1.17 95% CI 0.98-1.40). While there was no relationship between PM10 and cardiovascular admissions overall, there was a positive association with ischaemic heart disease in Indigenous people, greatest at a lag of 3 days (OR 1.71 95%CI 1.14-2.55).
Conclusion:
PM10 derived from vegetation fires was predominantly associated with respiratory rather than cardiovascular admissions. This outcome is consistent with the few available studies of ambient biomass smoke pollution. Indigenous people appear to be at higher risk of cardio-respiratory hospital admissions associated with exposure to PM10.
Related Concept Videos
01:24Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...
01:20Assessment of Ventilation I: Respiratory Rate
A Ventilation assessment is critical for monitoring a patient's health status. Respiration, one of the most accessible vital signs, provides insights into the function of numerous body systems and can indicate serious health issues, such as brainstem injuries from head trauma.
Critical Guidelines for Assessing Ventilation:
01:30Alterations in Respiration II
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes include...
01:23Chronic Obstructive Pulmonary Disease II: Emphysema
01:17Other Factors Affecting Respiration Centers
However, the ability to hold one's breath voluntarily is not limitless. When the CO2 concentration in the blood reaches a critical level,...
01:27Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History