Background

Climate change is increasing exposure to bushfire (wildfire) smoke and the entry of ultrafine particles into the brain. Bushfire smoke pollution has adverse impacts on the cerebrovascular system, and is linked to poor mental health and neurodegeneration.  Vulnerable populations include frontline rural firefighters and ageing populations. We are establishing an Australian cohort study of rural firefighters to determine the relationship between bushfire smoke exposure, overall health and neurological impact, with a focus on dementia risk.

Methods

We will collect data on bushfire smoke exposure and health phenotypes in >1,800 rural firefighters, recruiting in partnership with Queensland frontline response agencies. Participants will complete an online survey (paper versions available on request). Data will include demographics, memory and cognition, medical history, mental and physical health, lifestyle, online cognitive tests (Cogstate and Creyos) and home address data. In addition to the collection of data on fire smoke exposure during firefighting. Exposure to PM2.5 air pollution (particulate matter of 2.5 micrometre diameter or less) will be extrapolated, identifying both bushfire PM2.5 and non-bushfire PM2.5 at current and former residences using a combination of measured air pollution data with land use and remotely sensed (satellite) data.

Blood samples will be collected from 50 participants, selected based on extremes of bushfire smoke exposure. Plasma will be assayed using NULISA (Alamar Bioscience) CNS panel of 120 neuro-specific and inflammatory proteins.

Results

We will investigate markers of bushfire smoke-associated neurological impacts. We will test for an association of long term PM2.5 exposure with general health outcomes, comprehensive brain health measures (including Ecog, HBA Functional Assessment tool, and cognitive tests), and blood-based biomarkers for inflammation, neuronal injury and those specific to Alzheimer’s pathology (e.g. pTau217 and Aβ40/42). Our Prospective Imaging Study of Aging (PISA) will provide a control dataset for the comparison of the effect of PM2.5 in the general population (background exposure).

Conclusions

This research will identify indicators of elevated dementia risk and other brain health impacts associated with bushfire smoke exposure. Targeted screening and early intervention may mitigate the neurological consequences of bushfire smoke exposure.