The aims of the Respiratory Stream were to determine whether exposure to smoke from the Hazelwood coal mine fire is associated with respiratory symptoms, asthma control and lung inflammation, rate of decline in lung function and gas transfer and small airway function.

Who could participate in the Respiratory Stream?

• Participants in the Respiratory Stream must have participated in the Adult Survey and must have been selected for the Respiratory Stream. Selection of participants was carried out by a biostatistician using a random selection process which ensured that:
• participants were chosen objectively,
• participants were representative of their wider community,
• Morwell participants were selected in the same way as Sale participants,
• adults of all ages were represented,
• adults with and without a history of respiratory disease were represented, and
• both smokers and non-smokers were represented.

The selected participants received an invitation mailed to the address they provided during the Adult Survey.

Could people participate in the Respiratory Stream if they weren’t selected?

No. As described in the section above “Who could participate in the Respiratory Stream?”, selection of participants was carried out by a biostatistician using a random selection process that ensured the scientific validity of the study.
If we allowed people to self-refer into the study, this would likely have resulted in what is termed ‘selection bias’ whereby the participants who self-referred differed to the randomly selected participants in ways other than their level of mine fire smoke exposure. Self-referred participants may not be representative of their wider community. Selection bias would have made it much more difficult for the researchers to answer the research questions about the health effects of the mine fire event.

What did the Respiratory Stream appointment involve and how long did it take?

Participation in the Respiratory Stream Round 2 assessments involved:

1. Completing an online questionnaire about lung health, smoking history and, if a participant had asthma, their asthma control. The online questionnaire was emailed a few days prior to the clinic visit and took up to 45 minutes to complete.
2. Attending a clinic where participants undertook the following tests:
   
   a. Measurement of nitric oxide in exhaled breath. This involved blowing a single breath into a machine which measured a marker of inflammation in the lungs. Usually, two or three measurements were taken.
   
   b. Measurement of lung function. This test involved normal breathing on a machine while sound waves were used to measure airway narrowing and stiffness.
   
   c. Spirometry: This widely used test measured how hard and fast you were able to blow air in and out of the lungs. Up to eight measurements were made. This test was performed before and after inhaling a commonly used asthma reliever medication (Salbutamol, Ventolin™).
   
   d. Measurement of gas transfer: This test assessed how well gases such as oxygen could move from the lungs into the blood. This test involved breathing in a special gas mixture from a machine and holding your breath for a few seconds and then blowing back out into the machine. This test was usually performed two to three times. This test can be affected by the haemoglobin level in your blood. To measure this, a tiny drop of blood from your fingertip (like a blood glucose test) was collected.
3. In the weeks after the clinic appointment, participants were emailed an online food frequency questionnaire to complete at a time convenient to them. This was because there is a relationship between some types of foods and respiratory health. The email included more information about this questionnaire, which took about 30 minutes to complete. Decision about whether or not to complete the food frequency questionnaire had no impact on participation in other parts of the Hazelwood Health Study Respiratory Stream.

Who could participate in the Respiratory Stream or Cardiovascular Stream testing?

People were able to participate in the Respiratory and Cardiovascular Streams if they took part in the Hazelwood Health Study Adult Survey and were selected for the Respiratory or Cardiovascular Stream. If they were selected, they would have received an invitation letter mailed to the address they provided in the Adult Survey.

The Hazelwood Health Study was not a health service provider. The Study used standardised instruments to measure a limited set of health symptoms or signs which were specific to the research questions. The research was designed to measure changes in health at a population level and not at an individual level. For these reasons, the research could not determine whether any individuals’ health was impacted by the mine fire smoke, or whether any particular treatment should be recommended. Those decisions could only be made with a personalised medical consultation taking into consideration people's full medical history.

Why were only Morwell and Sale residents included in the testing?

Morwell was included because air pollution exposure modelling, conducted by the CSIRO, showed that Morwell was by far the town most exposed to smoke from the Hazelwood mine fire, with much lower exposure levels across other Latrobe Valley towns and beyond. Whilst there were many people from other towns who were impacted by the smoke, particularly those who worked in Morwell during the mine fire event, the highest exposure levels were experienced by Morwell residents who both worked and lived in the town for the duration of the event.

In contrast, the CSIRO modelling confirmed that Sale was minimally exposed to the mine fire smoke and selected areas of Sale were determined to be similar to Morwell in terms of their rural setting, age distribution and other socio-economic factors. These factors made Sale an ideal ‘comparison’ town which, at the time of the mine fire, should have had a similar health profile to that in Morwell.

By including these two towns in the Respiratory and Cardiovascular Streams, the researchers could compare the pattern of health in the ‘most’ exposed town against the pattern of health in a minimally exposed town, to measure the size/magnitude of the impact of the mine fire smoke.

The findings were then used to estimate the impact of the mine fire smoke on people from other towns across the Latrobe Valley, including people who didn’t live in Morwell but worked there.

It should be noted that other Hazelwood Health Study research streams included participants from across the Latrobe Valley, not just Morwell. They included the Early Life Follow-up (ELF) Stream, which included the families of more than 500 infants from across the Latrobe Valley; the Schools Study which included children from 20 schools across the Latrobe Valley; the Older People and Community Wellbeing Streams which conducted focus groups with people from across the Latrobe Valley; and Hazelinks which accessed deidentified ambulance, hospital, cancer and death data for the Latrobe Valley and other parts of Victoria.

Why weren’t emergency services personnel included in the Hazelwood Health Study?

Emergency service personnel who lived in Morwell, or in selected areas of Sale, were eligible for the Hazelwood Health Study Adult Survey. If they took part in the Adult Survey and were selected for the Respiratory or Cardiovascular Stream, then they were able to participate in those streams.

In regard to firefighters in particular, a research study designed to measure the health effects from deployment to the Hazelwood mine fire as opposed to the health effects from the firefighters’ numerous other deployments (to fires, chemical spills, motor vehicle accidents, floods etc.), would be designed very differently to the Hazelwood Health Study. Such a study, requiring a detailed deployment history from every eligible firefighter, could not be incorporated into the Hazelwood Health Study design.

If someone had died since the mine fire how was that person’s information collected?

This is very important health information that the Hazelwood Health Study needed to collect. That is why the Hazelinks Stream was developed. Hazelinks collected data on ambulance call-outs, hospital emergency presentations, hospital admissions, cancer diagnoses, and death records for the Latrobe Valley region and other parts of Victoria.

If I participated in the testing, how does that benefit me or my community?

Participants who participated in the Respiratory and Cardiovascular Streams received a $50 Woolworths gift card as reimbursement for their time, travel and inconvenience.

If their tests revealed any medical condition requiring further investigation or treatment, they were sent a letter with results to discuss with their GP.

This study provided valuable new information about long-term or chronic respiratory health or cardiovascular health conditions in Morwell and Sale residents and any associated impact of the mine fire smoke. The findings helped inform the local community, their health service providers and the State of Victoria Department of Health and Human Service (DHHS) of the long-term health needs of the Latrobe Valley and wider area.

If I participated in the testing, how was the privacy of my information protected?

All Respiratory Stream and Cardiovascular Stream procedures, including those in relation to the privacy and confidentiality of participant information, were reviewed by the Monash University Human Research Ethics Committee. The Committee approved the Respiratory Stream and Cardiovascular Stream procedures, satisfied that they met the requirements of the National Statement on Ethical Conduct in Human Research and the various provisions of the Privacy and Data Protection Act 2014.

More specifically, the privacy of participant information was protected in the following ways:

• All participants were allocated a unique ID number in place of personal information such as name, date of birth and address.
• Information collected was entered into a de-identified database via the secure Hazelwood Health Study remote desktop.
• Access to this remote desktop portal was only made available to authorised Study staff via a password-protected and secure login.
• Data collected from participants was locked within a secure environment both physically (paper files) and electronically.
• All staff who were involved in conducting the Hazelwood Health Study were trained and understood the importance of confidentiality and privacy.
• In addition, all Hazelwood Health Study staff signed confidentiality agreements as part of their employment.

Could people who lived in Morwell / Sale at the time of the mine fire but then moved still participate?

Yes. If they participated in the Adult Survey and were selected for the Respiratory or Cardiovascular research Streams, then they were eligible to participate. However, the testing took place in clinics in Morwell and Sale only, so they may have had to travel to take part. All participants received a $50 gift card as reimbursement for time, travel and inconvenience.

What if someone had a history of smoking or health conditions - were they still eligible?

Yes, information provided in the Adult Survey was used to ensure that people with, and without, a history of smoking or health conditions were included. Further information about these, and other health risk factors, was collected as part of the Respiratory and/or Cardiovascular Stream appointments.

If someone didn’t have any exposure to the mine fire smoke, was there any point in them participating?

It was important that the Hazelwood Health Study included people with little or no exposure, or moderate exposure to the smoke, so that their health could be compared with that of people who had high levels of exposure to the smoke. It was important that every person who received an invitation agreed to participate in the Study. If the Study only included people who felt that they had high levels of exposure, then the Study would have ended up with a biased understanding of the impacts of the smoke event. Speaking to people with different levels of exposure enabled the Study to better understand the impacts of the smoke event across the entire community and the wider region.

If the mine fire event didn’t affect someone's health, was there any point in them participating?

It was important that the Hazelwood Health Study included people who believed they had few or no health effects, as well as people who believed they had moderate or severe health effects from the mine fire smoke. It was important that every person who received an invitation agreed to participate in the Study.  If the Study only included people who believed their health had been affected by the mine fire event, then the Study would have ended up with a biased understanding of the impacts of the smoke event. Speaking to people with different health outcomes enabled the Study to better understand the impacts of the smoke event across the entire community and the wider region.

How were participants informed of the research results?

A core aspect of community engagement was our commitment to providing regular updates to the community as the study progressed. We spoke regularly with community groups and spoke at other community events. We provided regular newsletters, held community briefings, as kept people updated through social media and our website at hazelwoodhealthstudy.org.au