Vascular Responses Among Adults Four Years Post Exposure to 6 Weeks of Smoke from the Hazelwood Coal Mine Fire

Juan Mundisugih,1,2 Caroline X Gao,1,3 Jillian F Ikin,1 Michael J Abramson,1 David Brown,1 Sinjini Biswas,1,2 Elizabeth M Dewar,2,4 Danny Liew,1 Dion Stub1,2,4 1School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia; 2Department of Cardiology, Alfred Health, Melbourne, VIC, Australia; 3Centre for Youth Mental Health (Orygen), University of Melbourne, Melbourne, VIC, Australia; 4Baker Heart and Diabetes Institute, Melbourne, VIC, AustraliaCorrespondence: Jillian F Ikin, Tel +61 3 9903 0308, Email jill.blackman@monash.eduBackground and Aims: Mega-wild fires are exposing large communities to weeks or months of high concentration smoke-related fine particulate air pollution (PM). However, little research has examined the long-term vascular responses from exposure to PM of this concentration and duration. We investigated whether level of exposure to 6 weeks of PM from the 2014 Hazelwood coal mine fire was associated with abnormal vascular responses approximately four years later.Methods: A cross-sectional analysis was undertaken of 387 participants (225 exposed, 162 unexposed) aged 55– 89 years, 3.5– 4 years after the mine fire. The primary outcome was flow-mediated dilatation (FMD), with time to reach peak diameter as the secondary outcome. Other secondary markers included high-sensitivity C-reactive protein (hsCRP) and ischaemic Electrocardiogram (ECG) changes.Results: There was no evidence of a difference in FMD between participants with high, medium, low or no mine-fire related PM2.5 exposure (4.09% vs 4.06% vs 4.02% vs 3.98%, respectively, p=0.99). Likewise, there was no difference in hsCRP or ischaemic ECG changes. In contrast, there was evidence of a difference in time to peak diameter (p=0.002) with more unexposed participants reaching peak diameter within 30 seconds (36%) compared to those who had high, medium, or low exposure (23%, 22%, 13%, respectively). Multivariate ordinal logistic regression analysis suggested tha