Objectives The causes of kidney cancer are not well understood though occupational exposures are thought to play a role. Crystalline silica is a known human carcinogen, and despite previous links with kidney disease, there have been few studies investigating its association with kidney cancer. We addressed this research gap using a population-based case-control study of Canadian men.
Methods Questionnaire data were obtained from individuals with histologically confirmed kidney cancer, and population-based controls recruited from eight Canadian provinces (1994–1997). An industrial hygienist characterised participants’ lifetime occupational exposure, and their confidence in the assessment (possibly, probably or definitely exposed) to silica on three dimensions (intensity, frequency and duration), and cumulative exposure was estimated. Logistic regression was used to estimate ORs and 95% CIs, adjusting for potential confounders.
Results Nearly half of the 689 kidney cancer cases (49%) and 2369 controls (44%) had ever been occupationally exposed to crystalline silica. In a fully adjusted model, workers ever-exposed to silica had a slightly increased risk of kidney cancer relative to those who were unexposed (OR 1.10, 95% CI 0.92 to 1.32). Odds were modestly (and generally not statistically significantly) increased for models with duration of exposure and cumulative exposure, though exposure-response relationships were not evident.
Conclusions Our findings do not provide evidence that occupational exposure to crystalline silica increases risk of kidney cancer in men.
- kidney cancer
- crystalline silica
- occupational exposure
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Collaborators Canadian Cancer Registries Epidemiology Group: The Canadian Cancer Registries Epidemiology Research Group comprised a principal investigator from some of the provincial cancer registries involved in the National Enhanced Cancer Surveillance System: Farah McCrate, Eastern Health, Newfoundland; Ron Dewar, Nova Scotia Cancer Registry; Nancy Kreiger, Cancer Care Ontario; Donna Turner, Cancer Care Manitoba.
Contributors CEP led the analysis and writing of the paper (lead author). PJV was the PI of the study and generated the idea for the study, developed the analysis plan, and contributed to the editing and revision of the manuscript. M-ÉP and SAH were co-investigators on the grant and contributed to the idea for the study, the analysis plan, and editing and revision of the manuscript. LL and LK provided data cleaning and analysis support and helped with writing, editing and revision of the manuscript. LB worked on the data cleaning and analysis for the study, and contributed to writing, editing and revision of the manuscript.
Funding This study was funded by the Ontario Ministry of Labour. CEP was supported by a Canadian Institutes of Health Research Postdoctoral Fellowship.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval Carleton University Research Ethics Board.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.
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