{
  "abstract": "Objectives Benzene has been recognised as a cause of acute myeloid leukaemia by the International Agency for Research on Cancer (IARC) since 1979. In their 2017 evaluation of benzene, IARC concluded that positive associations were observed also for other histological subtypes of lymphohematopoietic (LH) cancers: chronic myeloid leukaemia, non-Hodgkin lymphoma, chronic lymphoid leukaemia, and multiple myeloma. There is a need to further clarify benzene’s association with these LH cancer subtypes, using causal inference methodology to assess the role of exposure time-windows. We aim to investigate the time-dependent effect of benzene exposure on LH cancer subtypes in offshore petroleum workers using a target trial emulation framework.Material and Methods We will use the Norwegian Offshore Petroleum Workers cohort and the Heliport cohort, encompassing 100,000 workers employed offshore 1965–2023. Inclusion criteria will be specified according to the causal roadmap framework. Between 1999–2023, 823 LH cancer cases were identified by linkage to the Cancer Registry of Norway. Start of follow-up (time zero) will be 1999 or at the start of employment and continue until cancer diagnosis, death, or end of follow-up. Benzene exposure will be assessed using an expert-developed job-exposure matrix. Data on potential confounding factors (e.g. smoking and non-offshore benzene exposure) will be retrieved from questionnaire and register data by linking the cohort to national registries.Results Results will be presented as cumulative incidence (absolute and relative risks) calculated by multi-state models accounting for death as a competing event and adjusted for confounders using inverse probability treatment weights producing propensity scores.Conclusion These cohorts, with time-dependent benzene exposure, enable application of a target trial emulation framework, which may provide new insights and contribute to important clarifications regarding benzene exposure and risk of the major histological subtypes of LH cancers, and hence follow up on the latest IARC evaluation of benzene.",
  "authors": [
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Sara Nafisi"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Leon AM Berge"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Niki Marjerrison"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Nita K Shala"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Ronnie Babigumira"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Tom K Grimsrud"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Marit B Veierød"
    },
    {
      "affiliations": [
        "Department of Research, Cancer Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway. Oslo Centre for Biostatistics and Epidemiology, Department of Biostatistics, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway"
      ],
      "name": "Jo S Stenehjem"
    }
  ],
  "title": "8289337 Causal inference in benzene exposure and lymphohematopoietic cancers: a study protocol",
  "uid": "0b2640a4-1afc-5a39-aee4-7dd3aed54a11"
}