Norwegian research on benzene exposure and cancer an update

Transcription

1 Norwegian research on benzene exposure and cancer an update Presentation for Expert Seminar arranged by Petroleum Safety Authority Norway on Benzene exposure and related cancer risk in the oil and gas industry Thursday 25 October 2018 Stavanger, Norway Tom K Grimsrud, Senior Researcher / Consultant Doctor Department of Research, Cancer Registry of Norway

2 Cancer incidence in benzene exposed, non-offshore (1) 1. Talibov M, Sormunen J, Hansen J, Kjaerheim K, Martinsen JI, Sparen P, Tryggvadottir L, Weiderpass E, Pukkala E. Benzene exposure at workplace and risk of colorectal cancer in four Nordic countries. Cancer Epidemiol. 2018;55: Kirkeleit J, Riise T, Bjørge T, Christiani DC, Bråtveit M, Baccarelli A, Mattioli S, Hollund BE, Gjertsen BT. Maternal exposure to gasoline and exhaust increases the risk of childhood leukaemia in offspring - a prospective study in the Norwegian Mother and Child Cohort Study. Br J Cancer Hadkhale K, Martinsen JI, Weiderpass E, Kjaerheim K, Sparen P, Tryggvadottir L, Lynge E, Pukkala E. Occupational exposure to solvents and bladder cancer: A population-based case control study in Nordic countries. Int J Cancer. 2017;140(8): Nordby K-C, Kristensen P, Grimsrud TK, Ulvestad B, Kjærheim K. [Incidence of lymphohaematological cancer among employees and students at the Rosenborg laboratories, NTNU. National Institute of Occupational Health, 2015: [In Norwegian] 5. Talibov M, Lehtinen-Jacks S, Martinsen JI, Kjærheim K, Lynge E, Sparén P, Tryggvadottir L, Weiderpass E, Kauppinen T, Kyyrönen P, Pukkala E. Occupational exposure to solvents and acute myeloid leukemia: a population-based, case-control study in four Nordic countries. Scand J Work Environ Health. 2014;40(5):

3 Cancer incidence in benzene exposed, non-offshore (2) 6. Skog A, Martinsen JI, Aalen OO, Grimsrud TK. [ The Sola project. Cancer incidence among former employees at an oil refinery and among dwellers in the surrounding area.] Oslo: Kreftregisteret, 2009: [In Norwegian] 7. Kristensen P, Hilt B, Svendsen K, Grimsrud TK. Incidence of lymphohaematopoietic cancer at a university laboratory: a cluster investigation. Eur J Epidemiol. 2008;23(1): Kristensen P, Hilt B, Svendsen K, Grimsrud TK. [Additional report Incidence of lymphohaematopoietic cancers at the Rosenborg laboratories, NTNU.) Oslo: National Institute of Occupational Health, 2007: [In Norwegian] 9. Kristensen P, Hilt B, Svendsen K, Grimsrud TK. [Incidence of lymphohaematopoietic cancers in students and employees at the Rosenborg laboratories, NTNU.] Oslo: National Institute of Occupational Health, 2007: [In Norwegian]

4 Cancer incidence and benzene, non-offshore, comments Three of the studies were based on occupation registered in national censuses (Norwegian: folketellinger) exposure estimates for occupational groups prepared at a national level Nordic cancer registry data Interestingly, the researchers not find any association betwen benzene exposure and acute myelogenic leucaemia (AML) most likely due to misclassification of exposure Four of the studies were conducted among workers and students at a Norwegian university laboratory (Rosenborg-laboratoriene), with virtually no data on exposure. Still, the cancer pattern was found to be in line with an effect from benzene exposure Two of the studies involved general population: 1) children of mothers exposed to benzene during pregnancy, and 2) residents around an oil refinery plus a small refinery worker cohort. Evidence of childhood leukaemia was found in children of exposed mothers

5 Epidemiology describes the cancer pattern Exposure Study group Disease / Cause of death 5

6 Epidemiology describes the cancer pattern Exposure data often «the weak leg» In Norwegian offshore petroleum industry, available and relevant exposure measurements were few, and the «study group» was hard to get hold of Exposure Study group Disease / Cause of death 6

7 Cancer incidence in offshore petroleum workers (1) Two groups (cohorts) of Norwegian offshore workers have been studied One Register-based cohort: (Norwegian State) Register of Employers and Employees One Survey-based cohort, questionnaires reporting occupational history, demographic data and lifestyle in 1998, held by the Cancer Registry of Norway The register-based cohort: no exposure data; coarse data on type of work (4 categories) Kirkeleit J, Riise T, Bjørge T, Moen BE, Bråtveit M, Christiani DC. Increased risk of oesophageal adenocarcinoma among upstream petroleum workers. Occup Environ Med. 2010;67(5): Kirkeleit J, Riise T, Bråtveit M, Moen BE. Increased risk of acute myelogenous leukemia and multiple myeloma in a historical cohort of upstream petroleum workers exposed to crude oil. Cancer Causes Control. 2008;19(1): Important findings: Elevated risk of acute myelogenous leukaemia (AML), multiple myeloma (MM), and oesophageal adenocarcinoma

8 Degree of overlap between the cohorts Survey-based cohort Register-based cohort (Figure 1 in Stenehjem et al, 2014)

9 Degree of overlap between the follow-up periods Follow-up of register-based cohort Survey-based cohort Register-based cohort

10 Degree of overlap between the follow-up periods Follow-up of survey-based cohort Follow-up of register-based cohort Survey-based cohort Register-based cohort

11 Cancer incidence in offshore petroleum workers (2) Relevant reports from the survey-based cohort NB: Exposure data developed by experts at the University of Bergen, Prof. Magne Bråtveit's group Exposure linked individuallly to cohort members according to work history (29 job categories) Stenehjem JS, Kjærheim K, Bråtveit M, Samuelsen SO, Barone-Adesi F, Rothman N, Lan Q, Grimsrud TK. Benzene exposure and risk of lymphohaematopoietic cancers in offshore oil industry workers. Br J Cancer. 2015; 112(9): Stenehjem JS, Robsahm TE, Bråtveit M, Samuelsen SO, Kirkeleit J, Grimsrud TK. Aromatic hydrocarbons and risk of skin cancer by anatomical site in male offshore petroleum workers. Am J Ind Med. 2017;60(8): Important findings: Dose-related elevated risks of acute myelogenous leukaemia (AML), of multiple myeloma (MM), and suggestively so of chronic lymphocytic leukaemia (CLL), according to cumulative exposure to benzene or average exposure intensity Increased risk of skin cancer on hands and forearm exposed to raw oil, possibly explained by exposure to PAHs and / or benzene

12 Risk of death from cardiovascular disease (%) Prevention paradox Forebyggingsparadokset For public health, more is achieved by moving the population average to the left than by identifying high risk individuals Risk of death from cardiovascular disease Distribution of population according to serum level of cholesterol Number of deaths from cardiovascular disease: Serum cholesterol (mmol/l) 15 (Source: Norwegian Institute of Public Health)

13 Risk of disease Prevention paradox applied to benzene Complying and reporting according to a threshold limit value (TLV) may be of little help if there is much going on at lower exposure levels For benzene, epidemiology needs exposure data below the TLV Exposure 15 Threshold limit value (Source: Norwegian Institute of Public Health)

14 Funding for new studies in offshore workers "Exposure-related risks of cancer in Norwegian offshore petroleum industry workers" Funding from The Research Council of Norway (governmental) Project period Salary for 2 PhD students and 1 postdoc fellow, supportive personnel, and current expenses Focus on respiratory cancer, urinary tract cancer, cancer in women offshore

15 Number of cancers by 2016 Cancer type (male, except for breast) No. Colon 183 Rectum 114 Pancreas 65 Bronchus and Lung 304 Melanoma of skin 170 Non-melanoma skin cancer 95 Mesothelioma 26 Prostate 1060 Kidney 101 Urinary bladder 149 Brain 75 Lymph and Bone marrow 236 Breast (women) 78

16 Future needs and important questions Needs: Update of work histories after 1998 A complete list of offshore petroleum industry workers Questions: How will the petroleum industry evaluate their work against benzene-related diseases without epidemiology? Can the activity be sustainable without good documentation and knowledge of the experience of human resources?