ORCID Profile
0000-0001-9150-9440
Current Organisations
Monash University
,
Cabrini Hospital
,
Alfred Health
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Publisher: BMJ
Date: 16-06-2023
DOI: 10.1136/OEMED-2023-108892
Abstract: High silica content artificial stone has been found to be associated with silicosis among stone benchtop industry (SBI) workers. The objectives of this study were to determine the prevalence of and risk factors for silicosis among a large cohort of screened SBI workers, and determine the reliability of respiratory function testing (RFT) and chest x-ray (CXR) as screening tests in this industry. Subjects were recruited from a health screening programme available to all SBI workers in Victoria, Australia. Workers undertook primary screening, including an International Labour Office (ILO) classified CXR, and subject to prespecified criteria, also underwent secondary screening including high-resolution CT (HRCT) chest and respiratory physician assessment. Among 544 SBI workers screened, 95% worked with artificial stone and 86.2% were exposed to dry processing of stone. Seventy-six per cent (414) required secondary screening, among whom 117 (28.2%) were diagnosed with silicosis (median age at diagnosis 42.1 years (IQR 34.8–49.7)), and all were male. In secondary screening, silicosis was associated with longer SBI career duration (12 vs 8 years), older age, lower body mass index and smoking. In those with silicosis, forced vital capacity was below the lower limit of normal in only 14% and diffusion capacity for carbon monoxide in 13%. Thirty-six (39.6%) of those with simple silicosis on chest HRCT had an ILO category 0 CXR. Screening this large cohort of SBI workers identified exposure to dry processing of stone was common and the prevalence of silicosis was high. Compared with HRCT chest, CXR and RFTs had limited value in screening this high-risk population.
Publisher: Wiley
Date: 23-01-2020
DOI: 10.1111/RESP.13766
Publisher: BMJ
Date: 23-06-2022
Publisher: Wiley
Date: 05-10-2020
DOI: 10.1111/RESP.13951
Publisher: Wiley
Date: 13-09-2019
DOI: 10.1111/RESP.13695
Abstract: Despite silica dust exposure being one of the earliest recognized causes of lung disease, Australia, USA, Israel, Turkey and other countries around the world have recently experienced significant outbreaks of silicosis. These outbreaks have occurred in modern industries such as denim jean production, domestic benchtop fabrication and jewellery polishing, where silica has been introduced without recognition and control of the hazard. Much of our understanding of silica-related lung disease is derived from traditional occupations such as mining, whereby workers may develop slowly progressive chronic silicosis. However, workers in modern industries are developing acute and accelerated silicosis over a short period of time, due to high-intensity silica concentrations, oxidative stress from freshly fractured silica and a rapid pro-inflammatory and pro-fibrotic response. Appropriate methods of screening and diagnosis remain unclear in these workers, and a significant proportion may go on to develop respiratory failure and death. There are no current effective treatments for silicosis. For those with near fatal respiratory failure, lung transplantation remains the only option. Strategies to reduce high-intensity silica dust exposure, enforced screening programmes and the identification of new treatments are urgently required.
Publisher: Wiley
Date: 14-04-2022
DOI: 10.1111/RESP.14257
Abstract: Artificial stone benchtops are a popular kitchen product, but dust from their preparation and installation contains respirable crystalline silica, which causes silicosis. Silicosis is a preventable, permanent lung disease. The aim of this study was to assess mental health in workers from the artificial stone benchtop industry at risk of silicosis. Workers from the artificial stone benchtop industry undergoing assessment for silica‐associated disease were included. Information on demographics occupational, medical and smoking history modified Medical Research Council dyspnoea scale Perceived Stress Scale (PSS‐10) questionnaire spirometry and chest x‐ray was collected. Univariate and multivariate regression analyses were conducted. Of the 547 participants, the majority were men, aged under 45 years, in the industry for less than 10 years. With each increase of dyspnoea score, PSS‐10 scores increased. Higher PSS‐10 scores were also observed in those no longer in the industry, with a history of anxiety or depression, attending assessment early in the programme and a medium exposure duration. Participants who used an interpreter reported lower stress. No difference was observed across job title, age, sex, smoking, spirometry or chest x‐ray categories after multivariate analysis. This study identified workers with dyspnoea as likely to report higher stress. Other factors, such as leaving the industry, early attendance and a history of anxiety or depression, are also helpful in identifying workers at risk of poorer mental health outcomes.
Publisher: American Thoracic Society
Date: 02-2022
Publisher: Informa UK Limited
Date: 02-12-2022
DOI: 10.1080/02770903.2020.1847931
Abstract: In 2014, a fire at an open cut coal mine in South-eastern Australia burned for about 6 weeks. Residents of the adjacent town were exposed to high levels of fine particulate matter (PM A cross-sectional analysis was undertaken in a group of exposed participants with asthma from Morwell ( There was no evidence that exposed participants had more severe asthma symptoms, worse lung function, or more eosinophilic airway inflammation than unexposed participants. However, there was some evidence that Morwell participants had more uncontrolled than well-controlled asthma, compared to the participants from Sale (adjusted relative risk ratio 2.71 95% CI: 1.02, 7.21, Three and a half years after exposure, coal mine fire smoke did not appear to be associated with more severe asthma symptoms or worse lung function but might be associated with poorer asthma control.
Publisher: BMJ
Date: 28-10-2021
DOI: 10.1136/OEMED-2020-106897
Abstract: The popularity of high silica content artificial stone has been associated with emergence of severe, progressive silicosis as a major health issue affecting workers in the stone benchtop industry. This population-based health assessment programme has been implemented with the aim of identifcation of silica-associated disease at a preclinical stage. All current and former workers from the stone benchtop industry in the State of Victoria are offered free health assessments. Primary evaluations include a standardised questionnaire, physical examination, spirometry and gas transfer assessment and International Labour Organisation-categorised chest X-ray. Secondary evaluations include high-resolution CT chest, blood tests and a respiratory physician evaluation. At the end of the first 12 months, 86/239 (36%) workers who had completed secondary evaluation were diagnosed with silicosis (65 simple silicosis and 21 complicated silicosis). 22 had worked in the industry for less than 10 years at the time of diagnosis. Of those with simple silicosis, 80% of workers reported breathlessness only with strenuous exercise (modified Medical Research Council score of 0), and lung function was well preserved (prebronchodilator forced vital capacity mean 99.8% predicted (SD 13.6), diffusion capacity of the lung for carbon monoxide mean 96.2% predicted (SD 18.0)). Antinuclear antibodies were detected in 37% with silicosis and 24% without silicosis. Early results from this comprehensive health assessment programme have indicated a high proportion of referred artificial stone benchtop workers have silicosis, including many with early-stage disease. The common finding of antinuclear antibodies suggest significant potential for autoimmune disease in this occupational group.
Publisher: Wiley
Date: 11-08-2022
DOI: 10.1002/RCR2.1021
Abstract: Pulmonary alveolar proteinosis (PAP) is a rare lung disease where there is accumulation of surfactant in the alveoli. It can be classified based on the underlying aetiology into three categories: primary, secondary and congenital. Autoantibodies to granulocyte‐macrophage colony‐stimulating factor (GM‐CSF‐Ab) are a key diagnostic feature of autoimmune PAP. High intensity occupational exposure and inhalation of toxic particles such as silica can cause a form of secondary PAP called acute silicoproteinosis. We describe a 26‐year‐old stone benchtop fabricator with silicoproteinosis following daily exposure to high levels of silica who had elevated serum GM‐CSF‐Ab. We discuss the role of GM‐CSF‐Ab in cases of PAP with occupational inhalational exposure and the challenges in its interpretation.
Publisher: Wiley
Date: 15-02-2020
DOI: 10.1111/ALL.14202
Abstract: Silicosis is an ancient and potentially fatal pneumoconiosis caused by exposure to respirable crystalline silica. Silicosis is historically a disease of miners however, failure to recognize and control the risk associated with silica exposure in contemporary work practices such as sandblasting denim jeans and manufacturing of artificial stone benchtops has led to re-emergence of silicosis around the world. This review outlines the mineralogy, epidemiology, clinical and radiological features of the various forms of silicosis and other silica-associated diseases. Perspective is provided on the most recent studies shedding light on pathogenesis, including the central role of innate immune effector cells and subsequent inflammatory cascades in propagating pulmonary fibrosis and the extrapulmonary manifestations, which uniquely characterize this pneumoconiosis. Clinical conundrums in differential diagnosis, particularly between silicosis and sarcoidosis, are highlighted, as is the importance of obtaining a careful occupational history in the patient presenting with pulmonary infiltrates and/or fibrosis. While silicosis is a completely preventable disease, unfortunately workers around the world continue to be affected and experience progressive or even fatal disease. Although no treatments have been proven, opportunities to intervene to prevent progressive disease, founded in a thorough cellular and molecular understanding of the immunopathology of silicosis, are highlighted.
Publisher: Wiley
Date: 17-02-2022
DOI: 10.1111/RESP.14230
Abstract: Inhalation of high concentrations of respirable crystalline silica (RCS) can lead to silicosis. RCS contains varying levels of iron, which can cause oxidative stress and stimulate ferritin production. This study evaluated iron‐related and inflammatory markers in control and silicosis patients. A cohort of stone benchtop industry workers ( n = 18) were radiologically classified by disease severity into simple or complicated silicosis. Peripheral blood and bronchoalveolar lavage (BAL) were collected to measure iron, ferritin, C‐reactive protein, serum amyloid A and serum silicon levels. Ferritin subunit expression in BAL and transbronchial biopsies was analysed by reverse transcription quantitative PCR. Lipid accumulation in BAL macrophages was assessed by Oil Red O staining. Serum iron levels were significantly elevated in patients with silicosis, with a strong positive association with serum ferritin levels. In contrast, markers of systemic inflammation were not increased in silicosis patients. Serum silicon levels were significantly elevated in complicated disease. BAL macrophages from silicosis patients were morphologically consistent with lipid‐laden foamy macrophages. Ferritin light chain (FTL) mRNA expression in BAL macrophages was also significantly elevated in simple silicosis patients and correlated with systemic ferritin. Our findings suggest that elevated iron levels during the early phases of silicosis increase FTL expression in BAL macrophages, which drives elevated BAL and serum ferritin levels. Excess iron and ferritin were also associated with the emergence of a foamy BAL macrophage phenotype. Ferritin may represent an early disease marker for silicosis, where increased levels are independent of inflammation and may contribute to fibrotic lung remodelling.
Publisher: Wiley
Date: 18-03-2022
DOI: 10.1111/RESP.14242
Abstract: Silicosis not a disease of the past. It is an irreversible, fibrotic lung disease specifically caused by exposure to respirable crystalline silica (RCS) dust. Over 20,000 incident cases of silicosis were identified in 2017 and millions of workers continue to be exposed to RCS. Identified case numbers are however a substantial underestimation due to deficiencies in reporting systems and occupational respiratory health surveillance programmes in many countries. Insecure workers, immigrants and workers in small businesses are at particular risk of more intense RCS exposure. Much of the focus of research and prevention activities has been on the mining sector. Hazardous RCS exposure however occurs in a wide range of occupational setting which receive less attention, in particular the construction industry. Recent outbreaks of silicosis associated with the fabrication of domestic kitchen benchtops from high‐silica content artificial stone have been particularly notable because of the young age of affected workers, short duration of RCS exposure and often rapid disease progression. Developments in nanotechnology and hydraulic fracking provide further ex les of how rapid changes in technology and industrial processes require governments to maintain constant vigilance to identify and control potential sources of RCS exposure. Despite countries around the world dealing with similar issues related to RCS exposure, there is an absence of sustained global public health response including lack of consensus of an occupational exposure limit that would provide protection to workers. Although there are complex challenges, global elimination of silicosis must remain the goal.
Publisher: Cold Spring Harbor Laboratory
Date: 20-10-2020
DOI: 10.1101/2020.10.14.20213033
Abstract: In 2014 the Hazelwood open cut coal mine burned for six weeks, exposing nearby residents to fine particulate matter (PM 2.5 ). The long-term health consequences are being evaluated as part of the Hazelwood Health Study (HHS). These analyses explore the association between PM 2.5 and chronic obstructive pulmonary disease (COPD). A s le of 346 exposed, and 173 unexposed, adults participated in the longitudinal Respiratory Stream of the HHS. Participants underwent spirometry and gas transfer measurements and answered validated respiratory questionnaires 3.5-4 years after the fire. In idual level mine fire-related PM 2.5 exposure was modelled. Multivariate linear regression and logistic models were fitted to analyse associations between mean and peak PM 2.5 exposure and clinical outcomes, stratified by smoking status. A 10 μg/m 3 increase in mean PM 2.5 exposure was associated with a 69% (95%CI: 11% to 158%) increase in odds of spirometry consistent with COPD amongst non-smokers and increased odds of chest tightness (odds ratio OR 1.30, 95%CI 1.03 to 1.64) and chronic cough (OR 1.24, 95%CI 1.02 to 1.51) in the previous 12 months in all participants. For current smokers, increments in mean PM 2.5 exposure were associated with higher odds of chronic cough in the preceding 12 months (OR 2.13, 95%CI 1.24 to 3.65). Almost four years after a six-week period of coal fire PM 2.5 exposure, we identified a dose-response association between exposure and COPD in non-smokers. With climate change a likely contributor to increased risk of landscape fires, the findings will inform policy decisions during future sustained smoke events. Are there long-term impacts of a six-week mine fire event generating PM 2.5 on COPD and related respiratory symptoms in adults? Almost 4 years after the mine fire, each 10 µg/m 3 increase in PM 2.5 exposure was associated with a 69% increase in odds of spirometry consistent with COPD amongst non-smokers, and a 30% increase in odds of chest tightness and 24% increase in odds of chronic cough amongst all participants. Amongst smokers, each 10 µg/m 3 increase in PM 2.5 was associated with a 113% increase in odds of chronic cough. With the recent megafires in Australia and the United States exposing communities to smoke for weeks to months, evidence of the long-term health impacts of similar duration PM 2.5 generating pollution events are needed to inform the public health response.
Publisher: Wiley
Date: 27-04-2022
DOI: 10.1111/RESP.14270
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No related grants have been discovered for Ryan Hoy.