Stonemason’s Silicosis Research
Preliminary findings of our research into Stonemasons with silicosis were recently published in the journal of the Asian Pacific Society of Respirology (APSR). These findings are from a retrospective review of silicosis identiﬁed within Queensland stonemasons since December 2018. In this study, B-reader chest radiograph reports conducted to the International Labour Organization (ILO) standard were collated to quantify disease severity on imaging, and medical charts from the treating Respiratory Physicians were reviewed.
The importance of publishing these results early was to boost awareness of this emerging health crisis. With Queensland being the first state to commence health screening late last year they now have the largest reported number of silicosis cases in stonemasons anywhere in the world! Queensland has been identified to only house 13% of all Australian stonemasons and bricklayers. When effective screening is implemented throughout the nation, Queensland stats may only be the tip of the iceberg.
High Resolution Computerised Tomography (HRCT) is more sensitive for screening and diagnosis of silicosis.
A crucial ‘take home’ from the stonemason silicosis study is that plain chest films showed low sensitivity for silicosis. Of the 78 silicosis cases investigated, 43% had normal chest x-ray findings. This means for screening of silicosis in stonemasons with a history of heavy dust exposure, HRCT is recommended, in addition to chest x-rays and spirometry testing, as reliance on chest x-ray alone may lead to “false negatives”. Previous other studies have also demonstrated higher sensitivity for HRCT than plain film for screening of pneumoconiosis.
To date the stonemason silicosis study has investigated 78 male cases of either accelerated or chronic silicosis caused by exposure to respirable crystalline silica (RCS). All men had been very heavily exposed to RCS dust during their employment.
Three high risk work practices, listed below, were used to evaluate the level of exposure, with 68% of individuals exposed to all three:
- occupational exposure to artiﬁcial stone for more than half their work history
- using personal protective equipment for less than half their work time and
- performing more than half their work using dry cutting techniques.
Following the discovery of this epidemic the use of dry cutting techniques has been banned in Queensland, in an effort to limit dust exposure levels. This is an important step as dry cutting of artificial stone material, which is made up of around 90% silica, results in dust exposure levels of 1000x higher than the legal occupational exposure limit for RCS.
These published findings represent the results of an initial pilot study, with further research planned to continue for the next 12 months. Of high importance is the need to understand the trajectory of disease in these men, as at the present time this is unknown.
*Dr Rhiannon McBean, who heads the research department at Uniting Care Medical Imaging, and her team currently have 12 research projects underway with ongoing research into dust induced lung diseases a primary focus. Wesley Dust Disease Research Centre.