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Original article
Job-exposure matrices addressing lifestyle to be applied in register-based occupational health studies
  1. Sesilje Bondo Petersen1,
  2. Esben Meulengracht Flachs1,
  3. Eva Irene Bossano Prescott2,
  4. Anne Tjønneland3,
  5. Merete Osler4,
  6. Ingelise Andersen5,
  7. Knud Juel6,
  8. Esben Budz-Jørgensen7,
  9. Henrik A Kolstad8,
  10. Vivi Schlünssen9,10,
  11. Jens Peter Bonde1
  1. 1 Department of Occupational and Environmental Medicine, Bispebjerg University Hospital, Copenhagen, Denmark
  2. 2 Department of Cardiology, Bispebjerg University Hospital, Copenhagen, Denmark
  3. 3 Danish Cancer Society Research Center, Copenhagen, Denmark
  4. 4 Research Centre for Prevention and Health, Glostrup, Denmark
  5. 5 Section of Social Medicine, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
  6. 6 National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark
  7. 7 Section of Biostatistics, Univetrsity of Copenhagen, Copenhagen, Denmark
  8. 8 Department of Occupational Medicine, Danish Ramazzini Centre, Aarhus University Hospital, Aarhus, Denmark
  9. 9 National Research Centre for Working Environment, Copenhagen, Denmark
  10. 10 Department of Public Health, Danish Ramazzini Centre, Aarhus University, Aarhus, Denmark
  1. Correspondence to Professor Jens Peter Bonde, Department of Occupational and Environmental Medicine, Bispebjerg Hospital, Copenhagen, DK-2400, Denmark; Jens.Peter.Ellekilde.Bonde{at}


Objectives Information about lifestyle factors in register-based occupational health studies is often not available. The objective of this study was therefore to develop gender, age and calendar-time specific job-exposure matrices (JEMs) addressing five selected lifestyle characteristics across job groups as a tool for lifestyle adjustment in register-based studies.

Methods We combined and harmonised questionnaire and interview data on lifestyle from several Danish surveys in the time period 1981–2013 for 264 054 employees registered with a DISCO-88 code (the Danish version of International Standard Classification of Occupations (ISCO)-88) in a nationwide register-based Danish Occupational Cohort. We modelled the probability of specified lifestyles in mixed models for each level of the four-digit DISCO code with age and sex as fixed effects and assessed variation in terms of intraclass correlation coefficients (ICCs) and exposure-level percentile ratios across jobs for six different time periods from 1981 through 2013.

Results The ICCs were overall low (0.26%–7.05%) as the within-job group variation was large relative to the between job group variation, but across jobs the calendar period-specific ratios between highest and lowest predicted levels were ranging from 1.2 to 6.9, and for the 95%/1% and the 75%/5% percentile ratios ranges were 1.1–2.8 and 1.1–1.6, respectively, thus indicating substantial contrast for some lifestyle exposures and some occupations.

Conclusions The lifestyle JEMs may prove a useful tool for control of lifestyle-related confounding in register-based occupational health studies where lacking information on individual lifestyle factors may compromise internal validity.

  • confounding
  • bias
  • behaviour
  • cohort study

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  • Contributors JPB, SBP and EMF conceived and designed the study. SBP and EMF analysed the data. SBP wrote the first draft which was revised by JPB. All authors contributed to the writing of the manuscript, and final version was approved by all authors.

  • Funding The study was funded by the Danish Working Environment Research Fund (43-2014-03/20140016763).

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement All data are stored at Statistics Denmark. Researcher can get online access to data, also from abroad, through contact the correspondng author who can apply for permission.

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