Long-term effects of extreme smoke exposure on COVID-19: A cohort study

BACKGROUND

In 2014, the Hazelwood coalmine fire shrouded the regional Australian town of Morwell in smoke and ash for 6 weeks. One of the fire's by-products, PM2.5 , is associated with an increased risk of COVID-19 and severe disease. However, it is unclear whether the effect persisted for years after exposure. In this study, we surveyed a cohort established prior to the pandemic to determine whether PM2.5 from the coalmine fire increased long-term vulnerability to COVID-19 and severe disease.

METHODS

From August to December 2022, 612 members of the Hazelwood Health Study's adult cohort, established in 2016/17, participated in a follow-up survey that included standardized items to capture COVID-19 cases, as well as questions about hospitalization and vaccinations. Associations were evaluated in crude and adjusted logistic regression models.

RESULTS

A total of 268 (44%) participants self-reported or met symptom criteria for having had COVID-19 at least once. All models found a positive association, with odds of COVID-19 increasing by between 4% and 30% for a 10 μg/m3 increase in coalmine fire-related PM2.5 exposure. However, the association was significant in only 2 of the 18 models. There were insufficient hospitalizations to examine severity (n = 7; 1%).

CONCLUSION

The findings are inconclusive on the effect of coalmine fire-related PM2.5 exposure on long-term vulnerability to COVID-19. Given the positive association that was robust to modelling variations as well as evidence for a causal mechanism, it would be prudent to treat PM2.5 from fire events as a long-term risk factor until more evidence accumulates.

Evaluating the impact of Hazelwood mine fire event on students' educational development with Bayesian interrupted time-series hierarchical meta-regression

BACKGROUND

Environmental disasters such as wildfires, floods and droughts can introduce significant interruptions and trauma to impacted communities. Children and young people can be disproportionately affected with additional educational disruptions. However, evaluating the impact of disasters is challenging due to difficulties in establishing studies and recruitment post-disasters.

OBJECTIVES

We aimed to (1) develop a Bayesian model using aggregated school-level data to evaluate the impact of environmental disasters on academic achievement and (2) evaluate the impact of the 2014 Hazelwood mine fire (a six-week fire event in Australia).

METHODS

Bayesian hierarchical meta-regression was developed to evaluate the impact of the mine fire using easily accessible aggregated school-level data from the standardised National Assessment Program-Literacy and Numeracy (NAPLAN) test. NAPLAN results and school characteristics (2008-2018) from 69 primary/secondary schools with different levels of mine fire-related smoke exposure were used to estimate the impact of the event. Using an interrupted time series design, the model estimated immediate effects and post-interruption trend differences with full Bayesian statistical inference.

RESULTS

Major academic interruptions across NAPLAN domains were evident in high exposure schools in the year post-mine fire (greatest interruption in Writing: 11.09 [95%CI: 3.16-18.93], lowest interruption in Reading: 8.34 [95%CI: 1.07-15.51]). The interruption was comparable to a four to a five-month delay in educational attainment and had not fully recovered after several years.

CONCLUSION

Considerable academic delays were found as a result of a mine fire, highlighting the need to provide educational and community-based supports in response to future events. Importantly, this work provides a statistical method using readily available aggregated data to assess the educational impacts in response to other environmental disasters.

Long-term impact of exposure to coalmine fire emitted PM2.5 on emergency ambulance attendances

BACKGROUND

Little is known about the long-term health effects of coalmine fire smoke exposure. The 2014 Hazelwood coalmine fire event in southeast Australia released smoke into surrounding areas for 6 weeks.

OBJECTIVES

We aimed to investigate whether individual-level exposure to coalmine fire-related PM_2.5 was associated with a long-term increase in ambulance attendances following a coalmine fire event.

METHODS

A total of 2223 residents from the most exposed town of Morwell were assessed for ambulance attendances after the Hazelwood event from April 1, 2014 to December 31, 2017. PM_2.5 exposure was estimated for each individual using participant self-reported location diary data during the event and modelled PM_2.5 concentrations. Recurrent event survival analysis was used to evaluate the relationship between PM_2.5 exposure and ambulance attendances.

RESULTS

For each 10 μg/m³ increase in mean coalmine fire-related PM_2.5 exposure, there was a 10% (adjusted hazard ratio [HR]:1.10, 95%CI:1.03-1.17) increase in the overall risk of ambulance attendances within 3.5 years after the coalmine fire. Exposure to PM_2.5 was also associated with increased risk of respiratory (HR: 1.21, 95%CI: 1.02-1.44) and cardiovascular (HR: 1.13, 95%CI: 1.01-1.28) related ambulance attendances.

CONCLUSION

These results demonstrate that exposure to coalmine fire smoke during the Hazelwood event was associated with a long-term health risk post the fire event, specifically for respiratory and cardiovascular conditions. These findings are important for effective implementation of health care services following future extended coalmine fire PM_2.5 events.

Long-term impact of coal mine fire smoke on lung mechanics in exposed adults

BACKGROUND AND OBJECTIVE

In 2014, a 6-week-long fire at the Hazelwood coal mine exposed residents in the adjacent town of Morwell to high concentrations of fine particulate matter with an aerodynamic diameter < 2.5 μm (PM_2.5 ). The long-term health consequences are being evaluated as part of the Hazelwood Health Study.

METHODS

Approximately 3.5-4 years after the mine fire, adults from Morwell (n = 346) and the comparison town Sale (n = 173) participated in the longitudinal Respiratory Stream of the Study. Individual PM_2.5 exposure was retrospectively modelled. Lung mechanics were assessed using the forced oscillation technique (FOT), utilizing pressure waves to measure respiratory system resistance (Rrs) and reactance (Xrs). Multivariate linear regression was used to evaluate associations between PM_2.5 and transformed Rrs at 5 Hz, area under the reactance curve (AX5) and Xrs at 5 Hz controlling for key confounders.

RESULTS

There were clear dose-response relationships between increasing mine fire PM_2.5 and worsening lung mechanics, including a reduction in post-bronchodilator (BD) Xrs5 and an increase in AX5. A 10 μg/m³ increase in mine fire-related PM_2.5 was associated with a 0.015 (95% CI: 0.004, 0.027) reduction in exponential (Xrs5) post-BD, which was comparable to 4.7 years of ageing. Similarly, the effect of exposure was associated with a 0.072 (0.005, 0.138) increase in natural log (lnAX5) post-BD, equivalent to 3.9 years of ageing.

CONCLUSION

This is the first study using FOT in adults evaluating long-term respiratory outcomes after medium-term ambient PM_2.5 exposure to coal mine fire smoke. These results should inform public health policies and planning for future events.

Impact of exposure to mine fire emitted PM2.5 on ambulance attendances: A time series analysis from the Hazelwood Health Study

BACKGROUND

For six weeks from February 9, 2014, smoke and ash from a fire in the Morwell open cut brown coal mine adjacent to the Hazelwood power station covered parts of the Latrobe Valley, in south eastern Australia.

AIMS

To evaluate the health impact of the mine fire, daily counts of ambulance attendances from July 2010 to March 2015 were analysed.

METHODS

Time series models were used to evaluate the relative risk of ambulance attendances during the mine fire, in comparison with the remainder of the analysis period, and to also assess the risk of ambulance attendances associated with lagged effects of exposure to mine fire-related PM_2.5 levels. The models controlled for factors likely to influence ambulance attendances including seasonality, long-term temporal trends, day of the week, daily maximum temperature and public holidays.

RESULTS

A 10 μg/m³ increase in fire-related PM_2.5 was found to be associated with a 42% (95%CI: 14-76%) increase in ambulance attendances for respiratory conditions and a 7% (0-14%) increase in all ambulance attendances over a 20-day lag period. A smaller effect associated with exposure to fire-related PM_2.5 was identified when assuming shorter lag effects. Similar results were identified when assessing whether ambulance attendances increased during the 30-day mine fire period. There was a 15% (8-21%) increased risk of ambulance attendances for all conditions and a 47% (19-81%) increased risk for respiratory conditions during the mine fire period.

CONCLUSIONS

Exposure to smoke and ash from a fire in an open cut brown coal mine was associated with increased ambulance attendances, particularly for respiratory conditions. These findings guide the development and implementation of effective and timely strategies and health service planning to respond and mitigate health risks that arise in affected communities during future major air pollution episodes.

The factors associated with distress following exposure to smoke from an extended coal mine fire

In February 2014, the coalmine adjacent to the Hazelwood Power Station in the Latrobe Valley of Victoria, Australia, caught fire, with residents from the nearby town of Morwell and the wider area exposed to smoke for six weeks. Although there was evidence linking the mine-fire event with psychological distress, no studies have evaluated the degree of distress in relation to the level of smoke exposure. We aimed to investigate the exposure-response relationship between particulate matter 2.5 μm or less in diameter (PM_2.5) released during the Hazelwood mine fire event and long-term symptoms of posttraumatic distress in the affected community, including the consideration of other key factors. A total of 3096 Morwell residents, and 960 residents from the largely unexposed comparison community of Sale, were assessed for symptoms of posttraumatic distress 2.5 years after the Hazelwood incident using the Impact of Events Scale-Revised (IES-R). Individual-level PM_2.5 exposure was estimated by mapping participants' self-reported location data on modelled PM_2.5 concentrations related to the mine fire. Multivariate linear regression was used to evaluate the exposure-response relationship. Both mean and peak exposure to mine fire-related PM_2.5 were found to be associated with participant IES-R scores with an interaction effect between age and mean PM_2.5 exposure also identified. Each 10 μg/m³ increase in mean PM_2.5 exposure corresponded to a 0.98 increase in IES-R score (95% CI: 0.36 to 1.61), and each 100 μg/m³ increase in peak PM_2.5 exposure corresponded to a 0.36 increase (95% CI: 0.06 to 0.67). An age-effect was observed, with the exposure-response association found to be stronger for younger adults. The results suggest that increased exposure to PM_2.5 emissions from the Hazelwood mine fire event was associated with higher levels of psychological distress associated with the mine fire and the most pronounced effect was on younger adults living in the affected community.

The association of coal mine fire smoke with hospital emergency presentations and admissions: Time series analysis of Hazelwood Health Study

OBJECTIVES

We aimed to examine the change in rates of hospital emergency presentations or hospital admissions during the coal mine fire, and their associations with the coal mine fire-related fine particles (PM_2.5).

METHODS

Daily data on hospital emergency presentations and admissions were collected from the Department of Health and Human Services for the period January 01, 2009 to June 30, 2015, at Statistical Area Level 2 (SA2). The coal mine fire-related PM_2.5 concentrations were modelled by the Chemical Transport Model coupled with the Cubic Conformal Atmospheric Model. A generalised additive mixed model was used to estimate the change in rates of hospital emergency presentations and hospital admissions during the coal mine fire period, and to examine their associations with PM_2.5 concentrations for smoke impacted areas, after controlling for potential confounders.

RESULTS

Compared with non-fire periods, we found increased risks of all-causes, respiratory diseases, and asthma related emergency presentations and hospital admissions as well as chronic obstructive pulmonary disease (COPD) related emergency presentations during the fire period. Associations between daily concentrations of coal mine fire-related PM_2.5 and emergency presentations for all-causes and respiratory diseases, including COPD and asthma, appeared after two days' exposure. Associations with hospital admissions for cerebrovascular and respiratory diseases appeared on the same day of exposure.

CONCLUSIONS

Coal mine fire smoke created a substantial health burden. People with respiratory diseases should receive targeted messages, follow self-management plans and take preventive medication during future coal mine fires.

Factors associated with hypertension and its management among older rural Australians

OBJECTIVES

Hypertension is a leading risk factor for death and disability. We aimed to estimate the prevalence of hypertension in an older rural Australian cohort and identify predictors of hypertension management.

DESIGN

Analysis of cross-sectional data collected from participants in a prospective cohort study.

SETTING

The Victorian rural towns of Morwell and Sale in 2018-2019.

PARTICIPANTS

A weighted random sample of 1119 eligible participants from Morwell or Sale, aged ≥55-90 years for men and ≥60-90 years for women, was drawn from the Hazelwood Health Study's Adult Survey cohort.

MAIN OUTCOME MEASURES

Blood pressure, body mass index, left ventricular hypertrophy by electrocardiogram, estimated glomerular filtration rate and glycosylated haemoglobin (HbA_1c ) were measured. Participants with hypertension were categorised as managed, undermanaged or unmanaged.

RESULTS

Testing undertaken of 498 participants estimated the weighted prevalence of hypertension (defined as blood pressure ≥ 140/90 mm Hg, a self-reported doctor diagnosis of hypertension or taking antihypertensive medication) to be 79.9% (95% confidence interval: 75.7-83.4). Of those, 54.5% (49.4-60.0) had managed hypertension (<140/90 mm Hg), 37.1% (32.3-42.1) undermanaged hypertension and 8.4% (5.9-11.9) a new finding of hypertension (unmanaged hypertension). Current employment (relative risk 1.47, 95% confidence interval: 1.06-2.02) and single marital status (relative risk 1.45, 1.4-1.84) were associated with under- or unmanaged hypertension. Compared with no hypertension, the hypertensive groups were more likely to demonstrate markers of end-organ damage such as left ventricular hypertrophy and impaired renal function.

CONCLUSION

Hypertension is a highly prevalent condition among older rural Australians which is suboptimally identified and managed.

Medically evaluated psychological and physical health of Australian Gulf War veterans with chronic fatigue

OBJECTIVE

The aim of this study was to evaluate fatigue in Australian Gulf War veterans and a military comparison group according to the 1994 chronic fatigue syndrome (CFS) definition and investigate the relation with exposures.

METHODS

Comprehensive medical, psychological and reported exposure assessments of 1,456 veterans and 1,588 comparison group in a cross-sectional study.

RESULTS

More Gulf War veterans had fatigue at all levels than did the military comparison group. The findings may be at least partly explained as an "active-deployment effect." The odds ratios increased with increasing clinical evaluation of the nature of the fatigue, even after adjustment for current psychiatric disorders in addition to other possible confounding factors.

CONCLUSION

Medically unexplained chronic fatigue was more common, but not more disabling, in veterans than in the comparison group, but veterans with unexplained chronic fatigue had poorer health than veterans without. Within both populations, CFS is uncommon and at a similar level to the general community.

Neurological status of Australian veterans of the 1991 Gulf War and the effect of medical and chemical exposures

BACKGROUND

Since the 1991 Gulf War, concerns have been voiced about the effects on the health of veterans of Gulf War related medical and chemical exposures.

METHODS

Our cross-sectional study compared 1424 male Australian Gulf War veterans and a randomly sampled military comparison group (n = 1548). A postal questionnaire asked about the presence of current neurological type symptoms, medically diagnosed neurological conditions, and medical and chemical exposures. A neurological examination was performed as part of a physical assessment.

RESULTS

Veterans have a higher prevalence of neurological type symptoms (ratio of means 1.4, 95% confidence interval (CI) 1.2-1.5). Although the odds ratio (OR) of lower limb neurological type symptoms and signs in veterans compared with the comparison group was increased (OR = 1.6, 95% CI 1.0-2.7), it was of borderline significance, and there was no difference between groups according to a Neuropathy Score based on neurological signs alone (ratio of means 1.1, 95% CI 0.9-1.3). The increased OR of neurological type symptoms and signs suggestive of a central nervous system disorder (OR = 1.8, 95% CI 1.0-3.1) was also of borderline significance. Veterans were not more likely to have self-reported medically diagnosed neurological conditions, or to have neurological type symptoms and signs suggestive of an anterior horn cell disorder (OR = 0.9, 95% CI 0.5-1.6). The total number of neurological type symptoms reported by veterans, but not the Neuropathy Score, was associated with Gulf War related exposures including immunizations and pyridostigmine bromide in dose-response relationships, anti-biological warfare tablets, solvents, pesticides, and insect repellents.

CONCLUSIONS

This study shows increased reporting of neurological type symptoms in Gulf War veterans, but no evidence for increased neurological effects based on objective physical signs. There may be a number of factors, including information bias, relating to increased neurological type symptom reporting in veterans.

Cognitive-existential group psychotherapy for women with primary breast cancer: a randomised controlled trial

BACKGROUND

We conducted a randomised, controlled trial of cognitive-existential group therapy (CEGT) for women with early stage breast cancer receiving adjuvant chemotherapy with the aim of improving mood and mental attitude to cancer.

METHODS

Women were randomised to 20 sessions of weekly group therapy plus 3 relaxation classes or to a control arm receiving 3 relaxation classes. Assessments, independently done at baseline, 6 and 12 months, included a structured psychiatric interview and validated questionnaires covering mood, attitudes to cancer, family relationships, and satisfaction with therapy.

RESULTS

Three hundred and three of 491 (62%) eligible patients participated over 3 years. Distress was high pre-intervention: 10% were diagnosed as suffering from major depression, 27% from minor depression and 9% from anxiety disorders. On an intention-to-treat analysis, there was a trend for those receiving group therapy (n=154) to have reduced anxiety (p=0.05, 2-sided) compared to controls (n=149). Women in group therapy also showed a trend towards improved family functioning compared to controls (p=0.07, 2-sided). The women in the groups reported greater satisfaction with their therapy (p<0.001, 2-sided), appreciating the support and citing better coping, self-growth and increased knowledge about cancer and its treatment. They valued the CEGT therapy. Overall effect size for the group intervention was small (d=0.25), with cancer recurrence having a deleterious effect in three of the 19 therapy groups. Psychologists as a discipline achieved a moderate mean effect size (d=0.52).

CONCLUSION

CEGT is a useful adjuvant psychological therapy for women with early stage breast cancer. Interaction effects between group members and therapists are relevant to outcome. Group-as-a-whole effects are powerful, but the training and experience of the therapist is especially critical to an efficacious outcome.

Psychological morbidity and quality of life in Australian women with early-stage breast cancer: a cross-sectional survey

OBJECTIVE

To determine the prevalence of psychological morbidity and describe quality of life in women with early-stage breast cancer.

DESIGN

Cross-sectional descriptive study (3 months after conservative breast surgery or mastectomy) of patients from nine general hospitals in Melbourne, Victoria, October 1994 to March 1997.

PARTICIPANTS

303 women with early-stage breast cancer entering a randomised trial of adjuvant psychological group therapy; mean age, 46 years (SD, 8).

MAIN OUTCOME MEASURES

Diagnostic and Statistical Manual of Mental Health (DSM)-IV psychiatric diagnoses generated by the Monash Interview for Liaison Psychiatry; quality-of-life data based on the the European Organization for Research and Treatment of Cancer quality-of-life questionnaire (QLQ)-C30 (core) and QLQ-BR23 (breast module) instruments.

RESULTS

45% of the women (135/303) had a psychiatric disorder; 42% (127) of the sample had depression or anxiety, or both; there was minor depression in 82 (27.1%), an anxiety disorder in 26 (8.6%), major depression in 29 (9.6%) and a phobic disorder in 21 (6.9%). 20% of women (61) had more than one disorder. On quality-of-life measures nearly one-third of the women felt less attractive and most had lost interest in sexual activity. There was substantial distress about hair loss. Symptoms of lymphoedema were described by 13 women (4.3%). Breast conservation surgery was associated with a better body image (P<0.01).

CONCLUSION

Women recently diagnosed with early-stage breast cancer have high rates of psychiatric and psychological disturbance. Quality of life is substantially affected. Clinicians should actively explore their patients' psychological adjustment to enable early recognition and treatment of these disorders.