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.
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/m(3) 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%).
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.
ObjectivesTo investigate mortality and the rates of incident cancer among a cohort of aluminium industry workers.MethodsAmong 4507 male employees who worked in either of two Australian prebake ...smelters for at least 3 months, data linkage was undertaken with the Australian National Death Index and Australian Cancer Database. Standardised Mortality Ratios (SMRs) and Standardised Incidence Rates (SIRs) were estimated for the whole cohort and for: production; maintenance and office workers. SMRs and SIRs were calculated by time since first employment.ResultsAmong production workers, there was an excess risk of mortality from mesothelioma (SMR 2.8, 95% CI 1.3 to 5.2), lung (SMR 1.4, 95% CI 1.0 to 1.8), prostate (SMR 1.9, 95% CI 1.3 to 2.7) and liver cancer (SMR 2.0, 95% CI 1.1 to 3.4) and the SIR was also increased for overall respiratory cancers, specifically lung cancers. An excess risk of death from stomach cancer (SMR 2.9, 95% CI 1.2 to 6.1) and Alzheimer’s disease (SMR 3.4, 95% CI 1.1 to 7.9) was seen among maintenance workers. The overall risk of death was similar to that of the Australian general population, as was mortality from cancers overall and non-malignant respiratory disease.ConclusionsNo excess risk of death from bladder cancer or non-malignant respiratory disease was found. Excess lung cancer mortality and incidence may be explained by smoking and excess mortality from mesothelioma may be explained by asbestos exposure. An excess risk of mortality from liver and prostate cancer has been shown in production workers and requires further investigation.
Millions of people can potentially be exposed to smoke from forest fires, making this an important public health problem in many countries.
In this study we aimed to measure the association between ...out-of-hospital cardiac arrest (OHCA) and forest fire smoke exposures in a large city during a severe forest fire season, and estimate the number of excess OHCAs due to the fire smoke.
We investigated the association between particulate matter (PM) and other air pollutants and OHCA using a case-crossover study of adults (≥ 35 years of age) in Melbourne, Australia. Conditional logistic regression models were used to derive estimates of the percent change in the rate of OHCA associated with an interquartile range (IQR) increase in exposure. From July 2006 through June 2007, OHCA data were collected from the Victorian Ambulance Cardiac Arrest Registry. Hourly air pollution concentrations and meteorological data were obtained from a central monitoring site.
There were 2,046 OHCAs with presumed cardiac etiology during our study period. Among men during the fire season, greater increases in OHCA were observed with IQR increases in the 48-hr lagged PM with diameter ≤ 2.5 μm (PM2.5) (8.05%; 95% CI: 2.30, 14.13%; IQR = 6.1 μg/m(3)) or ≤ 10 μm (PM10) (11.1%; 95% CI: 1.55, 21.48%; IQR = 13.7 μg/m(3)) and carbon monoxide (35.7%; 95% CI: 8.98, 68.92%; IQR = 0.3 ppm). There was no significant association between the rate of OHCA and air pollutants among women. One hundred seventy-four "fire-hours" (i.e., hours in which Melbourne's air quality was affected by forest fire smoke) were identified during 12 days of the 2006/2007 fire season, and 23.9 (95% CI: 3.1, 40.2) excess OHCAs were estimated to occur due to elevations in PM2.5 during these fire-hours.
This study found an association between exposure to forest fire smoke and an increase in the rate of OHCA. These findings have implications for public health messages to raise community awareness and for planning of emergency services during forest fire seasons.
ObjectivesTo investigate the mortality and cancer incidence of female firefighters, a group where there are limited published findings.MethodsParticipating fire agencies supplied records of ...individual firefighters including the number and type of incidents attended. The cohort was linked to the Australian National Death Index and Australian Cancer Database. Standardised mortality ratios and standardised cancer incidence ratios were calculated separately for paid and volunteer firefighters. Volunteer firefighters were grouped into tertiles by the duration of service and by a number of incidents attended and relative mortality ratios and relative incidence ratios calculated.ResultsFor volunteer firefighters (n=37 962), the overall risk of mortality and risk from all major causes of death were reduced when compared with the general population whether or not they had ever attended incidents. Volunteer firefighters had a similar cancer incidence when compared with the general population for most major cancer categories. Female volunteer firefighters have usually attended few fires. Of those who had turned out to incidents, only one-third had attended more than 12 fires about half the number for male volunteers. Mortality and cancer incidence for paid female firefighters (n=1682) were similar to the general population but the numbers were small and so power was limited.ConclusionsFemale volunteer firefighters have a cancer incidence similar to the general population but a reduced risk of mortality which is likely to be a result of a ‘healthy volunteer’ effect.Most of the paid female firefighters were relatively recent recruits and it will be important to monitor the health of this group as more women are recruited to front-line firefighting roles.
In 2014, wildfires ignited a fire in the Morwell open cut coal mine, Australia, which burned for six weeks. This study examined associations between self-reported respiratory outcomes in adults and ...mine fire-related PM2.5 smoke exposure. Self-reported data were collected as part of the Hazelwood Health Study Adult Survey. Eligible participants were adult residents of Morwell. Mine fire-related PM2.5 concentrations were provided by the Commonwealth Scientific and Industrial Research Organisation Oceans & Atmosphere Flagship. Personalised mean 24-h and peak 12-h mine fire-related PM2.5 exposures were estimated for each participant. Data were analysed by multivariate logistic regression. There was some evidence of an association between respiratory outcomes and mine fire PM2.5 exposure. Chronic cough was associated with an odds ratio (OR) of 1.13 (95% confidence interval 1.03 to 1.23) per 10 μg/m3 increment in mean PM2.5 and 1.07 (1.02 to 1.12) per 100 μg/m3 increment in peak PM2.5. Current wheeze was associated with peak PM2.5, OR = 1.06 (1.02 to 1.11) and chronic phlegm with mean PM2.5 OR = 1.10 (1.00 to 1.20). Coal mine PM2.5 smoke exposure was associated with increased odds of experiencing cough, phlegm and wheeze. Males, participants 18–64 years, and those residing in homes constructed from non-brick/concrete materials or homes with tin/metal roofs had higher estimated ORs. These findings contribute to the formation of public health policy responses.
ObjectiveTo assess the predictive value of bronchial hyper-responsiveness (BHR) for the subsequent development of respiratory symptoms, airflow limitation and decline in lung function among aluminium ...smelter workers.MethodsAn inception cohort study of new employees at two Australian aluminium smelters was conducted. Participants completed a modified British Medical Research Council respiratory questionnaire, spirometry and a methacholine bronchial challenge test at baseline and at annual follow-up reviews. BHR was defined as PD20 ≤4000 µg. Poisson and mixed effects models were fitted to respiratory symptoms and lung function (forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC)).ResultsBaseline interview and lung function testing were completed by 278 workers, who were followed for a median of 4 years. BHR at baseline, present in 82 workers, was not associated with incident wheeze risk ratio (RR)=1.07 (95% CI 0.74 to 1.55) and cough RR=0.78 (95% CI 0.45, 1.35), but there was some increased risk of chest tightness RR=1.40 (95% CI 0.99, 1.98) after adjustment for age, sex, smoking and atopy. BHR at baseline was associated with lower FEV1 and FVC, although the rate of annual decline in FEV1 or FVC was similar between those with or without BHR. The specificity of BHR was 77% for wheeze, 70% for cough and 77% for chest tightness, but the sensitivity was poor, at 33%, 24% and 39%, respectively.ConclusionMethacholine challenge testing at entry to employment was not sufficiently predictive of later adverse respiratory outcomes, and notwithstanding the study limitations is unlikely to be a useful pre-employment or preplacement screening test in the aluminium smelting industry.
No studies have investigated the cancer outcomes from high level medium duration coal mine fire fine particulate matter ⩽2.5 µm in diameter (PM2.5) exposure. We included 2208 Morwell residents ...(exposed) and 646 Sale residents (unexposed) who participated in the Hazelwood Health Study Adult Survey. Competing risk regression models were used to evaluate relationships between coal mine fire exposure and cancer incidence, adjusting for known confounders. There were 137 cancers in the exposed and 27 in the unexposed over 14 849 person-years of follow-up. A higher risk of cancer incidence was observed for Morwell participants (HR = 1.67 95% CI 1.05-2.67), but no evidence to suggest associations between PM2.5 exposure and incidence of all cancers (HR = 1.02 95% CI 0.91-1.13), or site-specific cancers. There is no strong evidence that exposure to high concentrations of mine fire-related PM2.5 over a prolonged period could explain the higher risk in exposed population in this study.
We investigated the association between respiratory symptoms and psychological distress in the context of a prolonged smoke event, and evaluated whether smoke exposure, or pre‐existing respiratory ...and mental health conditions, influenced the association. Three thousand ninety‐six residents of a rural town heavily exposed to smoke from the 6‐week Hazelwood coal mine fire, and 960 residents of a nearby unexposed town, completed Kessler's psychological distress questionnaire (K10) and a modified European Community Respiratory Health Survey. Logistic regression models evaluated associations between distress and respiratory symptoms, with interactions fitted to evaluate effect modification. Smoke exposed participants reported higher levels of distress than those unexposed, and participants reporting respiratory symptoms recorded higher levels of distress than participants without respiratory symptoms, irrespective of exposure. 5‐unit increments in K10 scores were associated with 21%–48% increases in the odds of reporting respiratory symptoms. There were significant interactions with pre‐existing asthma, chronic obstructive pulmonary disease and mental health conditions, but not with smoke exposure. Although participants with pre‐existing conditions were more likely to report respiratory symptoms, increasing distress was most strongly associated with respiratory symptoms among those without pre‐existing conditions. Communities exposed to landscape fire smoke could benefit from interventions to reduce both psychological and respiratory distress.
Purpose We aimed to measure mortality and cancer incidence in a cohort of lead-exposed workers by using blood lead levels to assess exposure. Methods The cohort comprised male lead workers. Subjects ...were matched to cancer and death registries. Observed death and cancer incidence rates were compared with population rates to obtain standardized mortality ratios (SMR) and standardized incidence ratios (SIR). Results There were 4114 male subjects with average follow-up time of 16.2 years, and 406 deaths were observed. There were significant results for overall death (SMR, 111; 95% confidence interval 95% CI, 101–123), digestive system deaths (SMR, 167; 95% CI, 110–250), and deaths from external causes (SMR, 135; 95% CI, 105–174). A total of 228 subjects had cancer, with an overall SIR of 83 (95% CI, 73–95); liver cancer SIR of 217 (95% CI, 103–454) and esophageal cancer SIR of 240 (95% CI, 129–447). The latter was seven-fold greater (SIR 755; 95% CI, 314–1813) among those with a blood lead level result above 30 μg/dL compared with population rates. No other increases in cancers were observed. Conclusions Overall mortality was elevated. Although incidence rates of overall cancer were low, further studies and analysis are required to investigate any biologically plausible associations between inorganic lead and liver or esophageal cancer.
ObjectivesAlthough an asthma-like syndrome has been recognised in aluminium smelter workers for over 70 years, the causal agent has been difficult to identify.MethodsAn inception cohort study was ...conducted at two Australian aluminium smelters where 446 employees participated over a period of 9 years. Cumulative exposures between interviews were estimated from job histories using a task exposure matrix based on measurements in the smelters. Participants completed an MRC respiratory questionnaire, spirometry and methacholine challenge test. Data were analysed with generalised estimating equations to allow for repeated measurements of each participant.ResultsWheeze and chest tightness, the two symptoms most closely related to asthma, showed associations with occupational exposures. SO2 exposure was significantly associated with these symptoms, bronchial hyper-responsiveness (BHR) to methacholine (a feature of asthma), airflow limitation (reduced forced expiratory volume in 1 second/forced vital capacity ratio) and longitudinal decline in lung function. Fluoride exposure was associated with the same outcomes, but less strongly. Inhalable dust and the benzene soluble fraction (BSF) were associated with symptoms of asthma and BHR. Although many of the exposures were highly correlated, further modelling suggested that of the known respiratory irritants, SO2 was more likely than fluoride to be primarily responsible for the symptoms observed. Fluoride, inhalable dust and SO2 were the most important airborne contaminants associated with effects on lung function.ConclusionsThe observed effects were detected at contaminant levels within occupational exposure standards, so further reductions are required, particularly in SO2 exposures.
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