What is prostate cancer?
In Canada, prostate cancer is the most commonly diagnosed cancer among men. Important risk factors for prostate cancer include age and family history, however, little is known about the modifiable risk factors for the disease, including occupational causes. Occupational exposures that affect the endocrine system, such as shift work, are of particular interest given that prostate cancer can be a hormone-sensitive malignancy.
Possible occupational risk factors
These exposures are possible risk factors for prostate cancer, but evidence is currently inconclusive.
- Metallic compounds (e.g. cadmium and arsenic)
- Exposure to x- and gamma-radiation
- Chemical exposures (e.g. rubber compounds, pesticides such as malathion, and diesel exhaust)
- Sedentary behaviour and physical inactivity
- Work-related psychological stress
- Shift work
- Whole body vibration
The greatest risks of prostate cancer were observed among workers employed in management and administration, transportation, construction and trades, firefighting, and police occupations.
White collar occupations
Increased risks of prostate cancer are observed across all management and administrative occupations, as well as in teaching occupations. A possible explanation for these findings could be increased sedentary behavior and low occupational physical activity in white collar work. Additionally, this finding could be related to a greater uptake of prostate cancer screening in this group relative to others. Given that many prostate tumours grow slowly, more frequent screening could have increased the number of diagnoses in this group that would not have been detected otherwise.
- Management and administration: 2.2 times the risk
- Teaching: 1.2 times the risk
Employment in multiple transportation occupations is associated with an increased risk of prostate cancer, including railway transport operating, motor transport operating, and stationary engine and utilities operating. Possible exposures that could lead to an increased risk of prostate cancer in these groups include sedentary behavior and physical inactivity, shift work, obesity and whole body vibration. Exposure to whole body vibration occurs when mechanical energy from vibrating surfaces is passed to the body either in standing or sitting positions. Although the role of whole body vibrations in prostate cancer etiology remains unclear, other prostate conditions like prostatitis and increasing testosterone levels have been linked to whole body vibration exposure.
- Transportation occupations: 1.2 times the risk
Metal product manufacturing
Elevated risks of prostate cancer are observed for metal-related occupations such as metal processing, metal machining, metal shaping and forming, and metal product fabricating and assembling. These types of jobs may expose workers to elevated levels of metallic compounds or whole body vibration, which are possible risk factors for prostate cancer.
- Foremen, metal processing and related: 1.9 times the risk
- Metal rolling: 1.5 times the risk
- Foremen, metal machining: 1.7 times the risk
- Foremen, metal shaping and forming (except machining): 2.2 times the risk
- Metal forging: 1.5 times the risk
Elevated risk of prostate cancer is observed in both firefighters and police. This could be related to shift work, sedentary behaviour or high levels of occupational stress among these groups. Firefighters may also be exposed to diesel engine exhaust while working in fire halls, which is a potential risk factor for prostate cancer.
- Firefighters: 1.6 times the risk
- Police: 1.2 times the risk
Relative Risk by Industry and Occupation
Figure 1. Risk of prostate cancer diagnosis among workers employed in each industry group relative to all others, Occupational Disease Surveillance System (ODSS), 1983-2016
Figure 2. Risk of prostate cancer diagnosis among workers employed in each occupation group relative to all others, Occupational Disease Surveillance System (ODSS), 1983-2016
Table of Results
Table 1. Surveillance of Prostate Cancer: Number of cases, workers employed, and hazard ratios in each industry (SIC)
|SIC Code *||Industry Group||Number of cases||Number of workers employed||Hazard Ratio (95% CI) †|
|1||Agriculture||361||26,402||0.60 (0.54, 0.67)|
|2/3||Forestry, Fishing and Trapping||213||10,223||0.79 (0.69, 0.90)|
|4||Mines, Quarries and Oil Wells||738||22,707||1.27 (1.18, 1.37)|
|5||Manufacturing||14,064||528,890||1.01 (0.99, 1.04)|
|6||Construction||4,077||202,142||0.86 (0.83, 0.89)|
|7||Transportation, Communication and Other Utilities||4,309||164,173||1.20 (1.16, 1.24)|
|8||Trade||5,200||291,020||0.74 (0.72, 0.76)|
|9||Finance, Insurance and Real Estate||429||15,220||1.31 (1.19, 1.44)|
|10||Community, Business and Personal Service||4,660||249,204||0.89 (0.87, 0.92)|
|11||Public Administration and Defense||4,026||121,480||1.49 (1.44, 1.54)|
|* SIC: Standard Industrial Classification (1970)|
|† Hazard ratio in each group relative to all others|
Table 2. Surveillance of Prostate Cancer: Number of cases, workers employed, and hazard ratios in each occupation (CCDO) group
|CCDO Code *||Occupation Group||Number of cases||Number of workers employed||Hazard Ratio (95% CI) †|
|11||Managerial, administrative and related||464||14,228||2.17 (1.98, 2.38)|
|21||Natural sciences, engineering and mathematics||538||20,814||1.30 (1.20, 1.42)|
|23||Social sciences and related fields||128||6,834||1.10 (0.92, 1.31)|
|27||Teaching and related||353||10,018||1.99 (1.79, 2.21)|
|31||Medicine and health||362||17,068||1.14 (1.03, 1.27)|
|33||Artistic, literary, recreational and related||156||8,400||1.11 (0.95, 1.30)|
|41||Clerical and related||2,133||96,316||1.00 (0.96, 1.04)|
|51||Sales||1,163||71,727||0.88 (0.83, 0.94)|
|61||Service||4,221||187,123||1.07 (1.04, 1.11)|
|71||Farming, horticultural and animal husbandry||586||39,236||0.68 (0.63, 0.74)|
|73||Fishing, hunting, trapping and related||8||518||0.66 (0.33, 1.33)|
|75||Forestry and logging||183||10,109||0.67 (0.58, 0.77)|
|77||Mining and quarrying, including oil and gas field||422||12,870||1.31 (1.19, 1.44)|
|81||Processing (mineral, metal, chemical)||1,403||62,878||0.93 (0.88, 0.98)|
|82||Processing (food, wood, textile)||1,372||67,325||0.87 (0.82, 0.91)|
|83||Machining and related||4,428||168,127||1.07 (1.04, 1.11)|
|85||Product fabricating, assembling and repairing||7,156||261,187||1.12 (1.09, 1.14)|
|87||Construction trades||5,284||211,378||1.09 (1.06, 1.12)|
|91||Transport equipment operating||3,998||153,882||1.20 (1.16, 1.24)|
|93||Materials handling and related, not elsewhere classified||2,392||121,957||0.80 (0.76, 0.83)|
|95||Other crafts and equipment operating||619||21,541||1.15 (1.06, 1.24)|
|99||Other occupations not elsewhere classified||3,554||174,651||0.85 (0.82, 0.88)|
|* CCDO: Canadian Classification Dictionary of Occupations (1971)|
|† Hazard ratio in each group relative to all others|
Please note that ODSS results shown here may differ from those previously published or presented. This may occur due to changes in case definitions, methodological approaches, and the ongoing nature of the surveillance cohort.