Medicine (RMH) - Research Publications

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    Vascular Responses Among Adults Four Years Post Exposure to 6 Weeks of Smoke from the Hazelwood Coal Mine Fire
    Mundisugih, J ; Gao, CX ; Ikin, JF ; Abramson, MJ ; Brown, D ; Biswas, S ; Dewar, EM ; Liew, D ; Stub, D (DOVE MEDICAL PRESS LTD, 2022)
    BACKGROUND 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 that township, Morwell (exposed) vs Sale (unexposed), but not level of PM2.5 exposure, was associated with delayed time to peak diameter (OR 2.71; 95% CI 1.56, 4.69). Smokers also had delayed time to peak diameter. CONCLUSION: There was no association between level of exposure to PM2.5 from the 6-week Hazelwood coal mine fire smoke event and reduced FMD, elevated hsCRP or ischaemic ECG four years later. Evidence of delayed time to peak diameter observed in adults from the exposed town, compared to an unexposed town, requires further investigation.
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    Factors associated with hypertension and its management among older rural Australians
    Betts, JM ; Gao, C ; Brown, D ; Ikin, J ; Maniam, R ; Stub, D ; Abramson, MJ ; Liew, D (WILEY, 2020-08)
    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 (HbA1c ) 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.
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    Markers of Cardiovascular Disease among Adults Exposed to Smoke from the Hazelwood Coal Mine Fire
    Betts, J ; Dewar, EM ; Stub, D ; Gao, CX ; Brown, DW ; Ikin, JF ; Zeleke, BM ; Biswas, S ; Abramson, MJ ; Liew, D (MDPI, 2021-02)
    Little research has examined the effects of high concentration, medium-duration smoke exposure on cardiovascular health. We investigated whether six weeks of exposure to smoke from the 2014 Hazelwood coal mine fire in Victoria (Australia), was associated with long-term clinical or subclinical cardiovascular disease approximately four years later, in adult residents of the towns of Morwell (exposed, n = 336) and Sale (unexposed, n = 162). The primary outcome was serum high sensitivity (hs) C-reactive protein (CRP). Blood pressure, electrocardiogram, flow mediated dilatation and serum levels of hs-troponin, N-terminal pro B-type natriuretic peptide and lipids were secondary outcomes. There was no significant difference in weighted median hsCRP levels between exposed and unexposed participants (1.9 mg/L vs. 1.6 mg/L, p = 0.273). Other outcomes were comparable between the groups. hsCRP was associated in a predictable manner with current smoking, obesity and use of lipid-lowering therapy. Four years after a 6-week coal mine fire, this study found no association between smoke exposure and markers of clinical or subclinical cardiovascular disease in exposed adults.
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    Recommended Intake of Key Food Groups and Cardiovascular Risk Factors in Australian Older, Rural-Dwelling Adults
    Owen, AJ ; Abramson, MJ ; Ikin, JF ; McCaffrey, TA ; Pomeroy, S ; Borg, BM ; Gao, CX ; Brown, D ; Liew, D (MDPI, 2020-03)
    This study examined the relationship between diet quality scores and cardiometabolic risk factors in regionally-dwelling older Australian adults with increased cardiovascular risk. This study was a cross-sectional analysis of demographic, anthropometric, and cardiometabolic risk factor data from 458 participants of the Cardiovascular Stream of the Hazelwood Health Study. Participants completed a 120 item semi-quantitative food frequency questionnaire. Multivariable linear regression adjusting for age, sex, smoking, physical activity, education, diabetes, and body mass index was used to examine the relationship between diet and cardiometabolic risk factors. Mean (SD) age of participants was 71 (8) years, and 55% were male. More than half of men and women did not meet recommended intakes of fibre, while 60% of men and 42% of women exceeded recommended dietary sodium intakes. Higher diet quality in terms of intake of vegetables, grains, and non-processed meat, as well as intake of non-fried fish, was associated with more favourable cardiometabolic risk profiles, while sugar-sweetened soft drink intake was strongly associated with adverse cardiometabolic risk factor levels. In older, regionally-dwelling adults, dietary public health strategies that address whole grain products, vegetable and fish consumption, and sugar-sweetened soft-drink intake may be of benefit in reducing cardiometabolic risk.