M. Dennekamp

The role of seasonal grass pollen on childhood asthma emergency department presentations.

Few studies have focused on the role of grass pollen on asthma emergency department (ED) presentations among children. None have examined whether a dose‐response effect exists between grass pollen levels and these asthma exacerbations.

Impact of Fine Particulate Matter (PM2.5) Exposure During Wildfires on Cardiovascular Health Outcomes

Background Epidemiological studies investigating the role of fine particulate matter (PM2.5; aerodynamic diameter <2.5 μm) in triggering acute coronary events, including out-of-hospital cardiac arrests and ischemic heart disease (IHD), during wildfires have been inconclusive. Methods and Results We examined the associations of out-of-hospital cardiac arrests, IHD, acute myocardial infarction, and angina (hospital admissions and emergency department attendance) with PM2.5 concentrations during the 2006–2007 wildfires in Victoria, Australia, using a time-stratified case-crossover study design. Health data were obtained from comprehensive health-based administrative registries for the study period (December 2006 to January 2007). Modeled and validated air exposure data from wildfire smoke emissions (daily average PM2.5, temperature, relative humidity) were also estimated for this period. There were 457 out-of-hospital cardiac arrests, 2106 emergency department visits, and 3274 hospital admissions for IHD. After adjusting for temperature and relative humidity, an increase in interquartile range of 9.04 μg/m3 in PM2.5 over 2 days moving average (lag 0-1) was associated with a 6.98% (95% CI 1.03% to 13.29%) increase in risk of out-of-hospital cardiac arrests, with strong association shown by men (9.05%,95%CI 1.63% to 17.02%) and by older adults (aged ≥65 years) (7.25%, 95% CI 0.24% to 14.75%). Increase in risk was (2.07%, 95% CI 0.09% to 4.09%) for IHD-related emergency department attendance and (1.86%, 95% CI: 0.35% to 3.4%) for IHD-related hospital admissions at lag 2 days, with strong associations shown by women (3.21%, 95% CI 0.81% to 5.67%) and by older adults (2.41%, 95% CI 0.82% to 5.67%). Conclusion PM2.5 exposure was associated with increased risk of out-of-hospital cardiac arrests and IHD during the 2006–2007 wildfires in Victoria. This evidence indicates that PM2.5 may act as a triggering factor for acute coronary events during wildfire episodes.

Impact of smoke from prescribed burning: Is it a public health concern?

Given the increase in wildfire intensity and frequency worldwide, prescribed burning is becoming a more common and widespread practice. Prescribed burning is a fire management tool used to reduce fuel loads for wildfire suppression purposes and occurs on an annual basis in many parts of the world. Smoke from prescribed burning can have a substantial impact on air quality and the environment. Prescribed burning is a significant source of fine particulate matter (PM2.5 aerodynamic diameter < 2.5µm) and these particulates are found to be consistently elevated during smoke events. Due to their fine nature PM2.5 are particularly harmful to human health. Here we discuss the impact of prescribed burning on air quality particularly focussing on PM2.5. We have summarised available case studies from Australia including a recent study we conducted in regional Victoria, Australia during the prescribed burning season in 2013. The studies reported very high short-term (hourly) concentrations of PM2.5 during prescribed burning. Given the increase in PM2.5 concentrations during smoke events, there is a need to understand the influence of prescribed burning smoke exposure on human health. This is important especially since adverse health impacts have been observed during wildfire events when PM2.5 concentrations were similar to those observed during prescribed burning events. Robust research is required to quantify and determine health impacts from prescribed burning smoke exposure and derive evidence based interventions for managing the risk. Implications:u2003Given the increase in PM2.5 concentrations during PB smoke events and its impact on the local air quality, the need to understand the influence of PB smoke exposure on human health is important. This knowledge will be important to inform policy and practice of the integrated, consistent, and adaptive approach to the appropriate planning and implementation of public health strategies during PB events. This will also have important implications for land management and public health organizations in developing evidence based objectives to minimize the risk of PB smoke exposure.

Relationship between cardiopulmonary mortality and cancer risk and quantitative exposure to polycyclic aromatic hydrocarbons, fluorides, and dust in two prebake aluminum smelters

ObjectivesWe examined the risk of mortality and cancer incidence with quantitative exposure to benzene-soluble fraction (BSF), benzo(a)pyrene (BaP), fluoride, and inhalable dust in two Australian prebake smelters.MethodsA total of 4,316 male smelter workers were linked to mortality and cancer incidence registries and followed from 1983 through 2002 (mean follow-up: 15.9xa0years, maximum: 20xa0years). Internal comparisons using Poisson regression were undertaken based on quantitative exposure levels.ResultsSmoking-adjusted, monotonic relationships were observed between respiratory cancer and cumulative inhalable dust exposure (trend pxa0=xa00.1), cumulative fluoride exposure (pxa0=xa00.1), and cumulative BaP exposure (pxa0=xa00.2). The exposure–response trends were stronger when examined across the exposed categories (BaP pxa0=xa00.1; inhalable dust pxa0=xa00.04). A monotonic, but not statistically significant trend was observed between cumulative BaP exposure and stomach cancer (nxa0=xa014). Bladder cancer was not associated with BaP or BSF exposure. No other cancer and no mortality outcomes were associated with these smelter exposures.ConclusionsThe carcinogenicity of Söderberg smelter exposures is well established; in these prebake smelters we observed an association between smelter exposures and respiratory cancer, but not bladder cancer. The exploratory finding for stomach cancer needs confirmation. These results are preliminary due to the young cohort and short follow-up time.

Occupational exposure to vapour, gases/fumes, dust and lung function in middle-aged population

Introduction: Studies suggest that 10% of children with an ARI have persistent cough at day 21. There are no studies in Indigenous children who have a high risk of chronic lung disease. We aimed to identify the incidence and outcomes of ARI with cough as a symptom in urban Indigenous children. Methods:This is a prospective study of Indigenous children aged<5 years registered with a primary health service. Children are followed for a period of 12 months via monthly contacts. Children who develop cough as a symptom at any time are followed weekly for 4 weeks to ascertain cough outcomes. Results: To date, 162 children are enrolled, totalling 1065 child-months of observation. Two-hundred ARI episodes with cough have been reported (29.6 episodes/100 child-months at risk). Thirty-four ARIs (17%) have progressed to persistent cough at day 28 in 24 children. Of these, 15 children had 1 episode, 5 had 2, 4 had 3 and 1 had 4 during the follow-up period. The majority of children with persistent cough were diagnosed (by a respiratory physician) with protracted bacterial bronchitis and/or bronchiectasis. Conclusions:The proportion of children developing persistent cough postARI is higher than that currently reported (10%) with the majority suggesting protracted bacterial infection. GrantSupport:AQUTAPAaward, aQCMRIProgramGrant, UQFoundation Research Excellence Award, a QUT Indigenous Health Research StartUpGrant and the NHMRCCRE for LungHealth in Aboriginal and TorresStrait Islander Children. Declaration of Interest: None to Declare