Ontario Uranium Miners Cohort Study Report Prepared for: The Canadian Nuclear Safety Commission February 2015 Prepared by: The Occupational Cancer Research Centre, Cancer Care Ontario 1 Ontario Uranium Miners Cohort Study Feb. 2015 ACKNOWLEGEMENTS This update of the Ontario Uranium Miners Cohort was conducted by the Occupational Cancer Research Centre (OCRC) with funding from the Canadian Nuclear Safety Commission. This report was prepared by Garthika Navaranjan, Colin Berriault, and Paul A. Demers from the OCRC and Minh Do, currently with the Public Health Agency of Canada and Paul Villeneuve from Carleton University. Loraine Marrett and John McLaughlin played key roles in the development of this cohort and the initiation of this project. Thanks are due to the staff of the Canadian Nuclear Safety Commission for their scientific comments and suggestions on the report. Special thanks are due to Robert Semenciw of the Public Health Agency of Canada who assisted with Canadian mortality and cancer incidence rates and to Douglas Chambers for his valuable insights and suggestions. Ontario Uranium Miners Cohort Study Feb. 2015 Table of Contents EXECUTIVE SUMMARY .......................................................................................................................................... i 1. INTRODUCTION AND BACKGROUND ............................................................................................................... 1 1.1 Canadian Uranium Mining History ............................................................................................................. 1 1.2 Uranium Mine Exposures and Health Effects ............................................................................................ 4 1.3 Ontario Radon Exposure Regulation .......................................................................................................... 7 2. URANIUM MINING COHORT STUDIES OVERVIEW ........................................................................................... 9 2.1 International Studies ................................................................................................................................ 16 2.2 Canadian Studies ...................................................................................................................................... 16 2.3 Ontario Studies ........................................................................................................................................ 16 3. RESEARCH OBJECTIVES................................................................................................................................... 18 4. METHODOLOGY ............................................................................................................................................. 21 Radon exposure assessment .......................................................................................................................... 24 Record Linkage and Mortality Ascertainment ............................................................................................... 25 4.1 Statistical Analysis .................................................................................................................................... 25 4.1.1 External Cohort Comparison ................................................................................................................. 25 4.1.2 Internal Cohort Analyses ....................................................................................................................... 27 4.1.3 Lung Cancer Morphology ...................................................................................................................... 30 4.1.4 Modern Miners ..................................................................................................................................... 31 5. RESULTS .......................................................................................................................................................... 32 5.1 External comparisons of mortality and cancer incidence ............................................................................ 38 5.2 Internal Analyses ...................................................................................................................................... 54 5.2.1 Radon exposure and lung cancer mortality ...................................................................................... 54 5.2.2 Attained Age ..................................................................................................................................... 56 5.2.3 Exposure rate .................................................................................................................................... 58 5.2.4 Time since first exposure .................................................................................................................. 59 5.2.5 Time since last exposure ................................................................................................................... 60 5.2.6 Age at first exposure ......................................................................................................................... 61 5.2.7 Inverse dose-rate .............................................................................................................................. 62 5.3 Radon exposure and lung cancer incidence ............................................................................................ 63 5.3.1 Attained Age ..................................................................................................................................... 66 5.3.2 Exposure rate .................................................................................................................................... 66 5.3.3 Time since first exposure .................................................................................................................. 67 5.3.4 Time since last exposure ................................................................................................................... 68 Ontario Uranium Miners Cohort Study Feb. 2015 5.3.5 Age at first exposure ......................................................................................................................... 69 5.4 Radon exposure and lung cancer morphology ........................................................................................ 70 5.5 Examination of risks among modern miners ........................................................................................... 75 5.6 Exploratory analyses of RDP exposure and cancer incidence and mortality for cancers other than lung .. 76 5.7 Exploratory analyses of RDP exposure and non-cancer mortality ............................................................... 78 5.8 Sensitivity Analysis Assessing Different Sources of Exposure Data ......................................................... 78 6. DISCUSSION .................................................................................................................................................... 82 REFERENCES ....................................................................................................................................................... 94 APPENDIX A: Exploratory Analyses of Potential Health Risks Associated with Gamma Radiation Exposure among Ontario Uranium Miners ..................................................................................................... 101 APPENDIX B: Sources of Exposure Uncertainty ............................................................................................... 115 Appendix C: Canadian Uranium Mine and Refinery Locations circa 2009....................................................... 123 Ontario Uranium Miners Cohort Study Feb. 2015 List of Tables Table 1: International Cohorts of Uranium Miners.............................................................................................. 9 Table 2: Overview of Previous Ontario Uranium Miner Cohort Studies............................................................ 16 Table 3: Basic characteristics of cohort members ............................................................................................. 34 Table 4: Exposure characteristics of cohort members by sex and mining region ............................................. 35 Table 5: Mortality for various non-cancer causes of death and 95% CIs, males (1954–2007) ......................... 38 Table 6: Cancer mortality, incidence and 95% CIs, male Ontario uranium miners ........................................... 39 Table 7: Overall mortality, incidence and 95% CIs, female Ontario uranium miners ........................................ 41 Table 8: Mortality for non-cancer causes of death and 95% CIs, males with gold mining experience ............ 42 Table 9: Cancer mortality, incidence and 95% CIs, males with gold mining experience ................................... 43 Table 10: Mortality for non-cancer causes of death and 95% CIs, males without gold mining experience ..... 44 Table 11: Cancer mortality, incidence and 95% CIs, males without gold mining experience ........................... 45 Table 12: Mortality for non-cancer causes of death and 95% CIs, males with only Elliot Lake experience ...... 47 Table 13: Cancer mortality, incidence and 95% CIs, males with only Elliot Lake experience............................ 48 Table 14: Mortality for non-cancer causes of death and 95% CIs, males