To investigate the chronic disease and cancer experience of an Ontario hard rock mining cohort in relation to occupational factors such as duration of employment in mining and the type of mining performed.
Mining is an important industry in Ontario, employing thousands of workers to extract ores from underground mines and quarries. Despite the economic benefits, there are adverse health consequences. In addition to the physical dangers posed by mining activities, miners are also exposed to a variety of known carcinogens including crystalline silica, diesel exhaust, radon decay products, arsenic, cadmium, nickel, and chromium. Many of these exposures can have both short and long-term adverse health effects contributing to the development of cancers and other chronic diseases.
The long-term health concerns of these miners were recognized in the early days of mining. These concerns provided the impetus for the development and maintenance of the Mining Master File (MMF). The MMF is a centralized database of information on 93,000 Ontario mining industry workers who were employed until the program was discontinued in 1988. The MMF data was collected during required annual medical examinations from 1928 to 1988 for underground miner certification by the province. This included mining employment histories spanning 1877 to 1988.
The first step in this project was to create a research platform for investigating relationships between employment in the Ontario mining industry and occupational disease. The research platform was developed by using the Mining Master File (MMF) to create a retrospective cohort of mine workers from various mines in Ontario. The cohort was linked to a number of administrative health databases that provide information on health outcomes, including: Ontario Health Insurance Plan’s Registered Persons Database (RPDB), the Ontario Health Insurance Plan (OHIP) Claims database, the Discharge Abstract Database (DAD), the National Ambulatory Care Reporting System (NACRS), and the Ontario Cancer Registry (OCR). This research platform continues to be used to explore the cancer incidence and mortality experience of the cohort, as well as chronic disease risks.
The final cohort file consisted of 61,397 male and 161 female workers employed in Ontario mines between 1928 and 1988 and successfully linked to Ontario’s health databases. Due to small numbers, female workers were excluded from further analyses.
The cohort has been used to assess the relationship between mining and several health outcomes, including lung cancer and silica exposure, chronic respiratory diseases, cancer risk by ore type, cardiovascular disease and aluminum powder exposure, and rare cancers.
The MMF is a powerful research platform to investigate health outcomes among Ontario miners.
This study was funded by a grant from the Ontario Ministry of Labour, Training and Skills Development’s Research Opportunities Program.
Quantitative silica dust exposure and lung cancer incidence in hard rock miners: 1.6 million person-years of follow-up in the Mining Master File cohort study
Incidence of cardiovascular disease in a cohort of mine workers exposed to ultrafine aluminum powder in Ontario, Canada
O6B.2 Cancer risk by ore type in a mixed miners cohort
Chronic respiratory disease in the Ontario mining industry
Exploring the etiology of rare cancers using a large multi-ore mining cohort
