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  3. Long working hours and alcohol use: systematic review and meta-analysis of published studies and unpublished individual participant data
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Research

Long working hours and alcohol use: systematic review and meta-analysis of published studies and unpublished individual participant data

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.g7772 (Published 13 January 2015) Cite this as: BMJ 2015;350:g7772
  1. Marianna Virtanen, professor1,
  2. Markus Jokela, associate professor2,
  3. Solja T Nyberg, statistician1,
  4. Ida E H Madsen, researcher3,
  5. Tea Lallukka, specialist researcher14,
  6. Kirsi Ahola, team leader1,
  7. Lars Alfredsson, professor of epidemiology56,
  8. G David Batty, reader in epidemiology789,
  9. Jakob B Bjorner, professor3,
  10. Marianne Borritz, assistant professor10,
  11. Hermann Burr, scientist11,
  12. Annalisa Casini, lecturer12,
  13. Els Clays, postdoctoral researcher13,
  14. Dirk De Bacquer, professor13,
  15. Nico Dragano, professor14,
  16. Raimund Erbel, professor of medicine15,
  17. Jane E Ferrie, senior research fellow716,
  18. Eleonor I Fransson, associate professor51718,
  19. Mark Hamer, principal research associate7,
  20. Katriina Heikkilä, specialist researcher19,
  21. Karl-Heinz Jöckel, professor20,
  22. France Kittel, professor of health psychology and research methodology12,
  23. Anders Knutsson, professor of public health21,
  24. Markku Koskenvuo, professor of epidemiology4,
  25. Karl-Heinz Ladwig, professor of psychosomatic medicine22,
  26. Thorsten Lunau, researcher14,
  27. Martin L Nielsen, consultant23,
  28. Maria Nordin, associate professor of psychology1724,
  29. Tuula Oksanen, assistant chief medical officer1,
  30. Jan H Pejtersen, senior researcher25,
  31. Jaana Pentti, statistician1,
  32. Reiner Rugulies, professor of psychosocial work environment and health326,
  33. Paula Salo, professor of psychology127,
  34. Jürgen Schupp, professor of sociology2829,
  35. Johannes Siegrist, professor14,
  36. Archana Singh-Manoux, research director730,
  37. Andrew Steptoe, British Heart Foundation professor of psychology7,
  38. Sakari B Suominen, professor313233,
  39. Töres Theorell, professor emeritus17,
  40. Jussi Vahtera, professor of public health13134,
  41. Gert G Wagner, professor283536,
  42. Peter J M Westerholm, professor emeritus37,
  43. Hugo Westerlund, professor of epidemiology17,
  44. Mika Kivimäki, professor of social epidemiology147
  1. 1Finnish Institute of Occupational Health, 00250 Helsinki, Finland
  2. 2Institute of Behavioral Sciences, University of Helsinki, Helsinki, Finland
  3. 3National Research Centre for the Working Environment, Copenhagen, Denmark
  4. 4Department of Public Health, Faculty of Medicine, University of Helsinki, Finland
  5. 5Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
  6. 6Centre for Occupational and Environmental Medicine, Stockholm County Council, Sweden
  7. 7Department of Epidemiology and Public Health, University College London, London, UK
  8. 8Alzheimer Scotland Dementia Research Centre, University of Edinburgh, Edinburgh, UK
  9. 9Centre for Cognitive Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK
  10. 10Department of Occupational Medicine, Koge Hospital, Koge, Denmark
  11. 11Federal Institute for Occupational Safety and Health (BAuA), Berlin, Germany
  12. 12School of Public Health, Université Libre de Bruxelles (ULB), Brussels, Belgium
  13. 13Department of Public Health, Ghent University, Ghent, Belgium
  14. 14Institute for Medical Sociology, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany
  15. 15Department of Cardiology, West-German Heart Center Essen, University Duisburg-Essen, Essen, Germany
  16. 16School of Social and Community Medicine, University of Bristol, Bristol, UK
  17. 17Stress Research Institute, Stockholm University, Stockholm, Sweden
  18. 18School of Health Sciences, Jönköping University, Jönköping, Sweden
  19. 19School of Medicine, University of Tampere, Tampere, Finland
  20. 20Institute for Medical Informatics, Biometry, and Epidemiology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany
  21. 21Department of Health Sciences, Mid Sweden University, Sundsvall, Sweden
  22. 22Helmholtz Zentrum München (German Research Center for Environmental Health (GmbH)), 85764 Oberschleißheim, Germany
  23. 23Unit of Social Medicine, Frederiksberg University Hospital, Copenhagen, Denmark
  24. 24Department of Psychology, Umeå University, Umeå, Sweden
  25. 25Danish National Centre for Social Research, Copenhagen, Denmark
  26. 26Department of Public Health and Department of Psychology, University of Copenhagen, Copenhagen, Denmark
  27. 27Department of Psychology, University of Turku, Turku, Finland
  28. 28German Institute for Economic Research, Berlin, Germany
  29. 29Free University of Berlin, Berlin, Germany
  30. 30Inserm U1018, Centre for Research in Epidemiology and Population Health, Villejuif, France
  31. 31Department of Public Health, University of Turku, Turku, Finland
  32. 32Nordic School of Public Health, Gothenburg, Sweden
  33. 33Folkhälsan Research Center, Helsinki, Finland
  34. 34Turku University Hospital, Turku, Finland
  35. 35Max Planck Institute for Human Development, Berlin, Germany
  36. 36Berlin University of Technology, Berlin, Germany
  37. 37Occupational and Environmental Medicine, Uppsala University, Uppsala, Sweden
  1. Correspondence to: M Virtanen marianna.virtanen{at}ttl.fi
  • Accepted 17 November 2014

Abstract

Objective To quantify the association between long working hours and alcohol use.

Design Systematic review and meta-analysis of published studies and unpublished individual participant data.

Data sources A systematic search of PubMed and Embase databases in April 2014 for published studies, supplemented with manual searches. Unpublished individual participant data were obtained from 27 additional studies.

Review methods The search strategy was designed to retrieve cross sectional and prospective studies of the association between long working hours and alcohol use. Summary estimates were obtained with random effects meta-analysis. Sources of heterogeneity were examined with meta-regression.

Results Cross sectional analysis was based on 61 studies representing 333 693 participants from 14 countries. Prospective analysis was based on 20 studies representing 100 602 participants from nine countries. The pooled maximum adjusted odds ratio for the association between long working hours and alcohol use was 1.11 (95% confidence interval 1.05 to 1.18) in the cross sectional analysis of published and unpublished data. Odds ratio of new onset risky alcohol use was 1.12 (1.04 to 1.20) in the analysis of prospective published and unpublished data. In the 18 studies with individual participant data it was possible to assess the European Union Working Time Directive, which recommends an upper limit of 48 hours a week. Odds ratios of new onset risky alcohol use for those working 49-54 hours and ≥55 hours a week were 1.13 (1.02 to 1.26; adjusted difference in incidence 0.8 percentage points) and 1.12 (1.01 to 1.25; adjusted difference in incidence 0.7 percentage points), respectively, compared with working standard 35-40 hours (incidence of new onset risky alcohol use 6.2%). There was no difference in these associations between men and women or by age or socioeconomic groups, geographical regions, sample type (population based v occupational cohort), prevalence of risky alcohol use in the cohort, or sample attrition rate.

Conclusions Individuals whose working hours exceed standard recommendations are more likely to increase their alcohol use to levels that pose a health risk.

Footnotes

  • Contributors: MV and MK developed the hypothesis and study design and supervised this study. MJ, MV, SN, IM, and TL performed statistical analyses. All authors contributed to study concept and design, analysis and interpretation of data, and drafting or critical revision of the manuscript for important intellectual content, or in addition, data acquisition. MV and KA performed the literature searches and/or screened papers. MK, TT, RR, and ND obtained funding for the IPD-Work Consortium. MJ, SN, and MK had full access to individual participant data in the study and take responsibility for the integrity of the unpublished data and the accuracy of the data analysis. MV is guarantor.

  • Funding: The IPD-Work Consortium is supported by the EU New OSH ERA Research Program (funded by the Finnish Work Environment Fund and the Academy of Finland, Finland; the Swedish Research Council for Health, Working Life and Welfare, Sweden; the German Social Accident Insurance, Germany; and the Danish Work Environment Research Fund, Denmark); the BUPA Foundation (grant 22094477), and the Dutch Ministry of Social Affairs and Employment, Netherlands. MV is supported by the Academy of Finland (grants 258598, 265174), MK is supported by the Medical Research Council (grant K013351), the Economic and Social Research Council, and the US National Institutes of Health (grants R01HL036310 and R01AG034454), and SN is supported by the Finnish Work Environment Fund. AS is a BHF professor. Funding bodies for each participating cohort study are listed on their websites. The sponsors had no role in design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of this manuscript.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work other than those mentioned above; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Each constituent study with individual participant data was approved by the relevant local or national ethics committee, and all participants gave informed consent to participate.

  • Data sharing: No additional data from our meta-analysis are available. Data for ACL, ALAMEDA, BCS, HILDA, MIDUS, NCDS, NHANES-I, NLSY, NSFH, SOEP, WLSG, and WLSS studies are publicly available to researchers. In addition, most constituent studies of the IPD-Work consortium have an established data sharing policy.

  • Transparency: MV affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.

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