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Åsa Tornberg

Associate professor

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Occupational sedentariness and breast cancer risk


  • Anna Johnsson
  • Per Broberg
  • Anders Johnsson
  • Åsa B. Tornberg
  • Håkan Olsson

Summary, in English

Background: Epidemiological studies have indicated that physical activity reduces the risk of developing breast cancer. More recently, sedentary behavior has been suggested as a risk factor independent of physical activity level. The purpose of the present study was to investigate occupational sedentariness and breast cancer risk in pre- and postmenopausal women. Materials and methods: In a population-based prospective cohort study (n = 29 524), working history was assessed by a questionnaire between 1990 and 1992. Participants were classified as having: (1) sedentary occupations only; (2) mixed occupations or (3) non-sedentary occupations only. The association between occupational sedentariness and breast cancer incidence was analyzed by Cox regression, adjusted for known risk factors and participation in competitive sports. Results: Women with a working history of occupational sedentariness had a significantly increased risk of breast cancer (adjusted HR 1.20; 95% CI 1.05, 1.37) compared with those with mixed or non-sedentary occupations. The association was stronger among women younger than 55 years (adjusted HR 1.54; 95% CI 1.20, 1.96), whereas no association was seen in women 55 years or older. Adjustment for participation in competitive sports did not change the association. Conclusions: We found that occupational sedentariness was associated with increased breast cancer risk, especially in women younger than 55 years. This may be a modifiable risk factor by planning breaks during the working day. Whether this reduces the risk of breast cancer needs to be further studied.


  • EpiHealth: Epidemiology for Health
  • Medical oncology
  • Tumor microenvironment
  • Human Movement: health and rehabilitation
  • BioCARE: Biomarkers in Cancer Medicine improving Health Care, Education and Innovation

Publishing year







Acta Oncologica





Document type

Journal article


Taylor & Francis


  • Cancer and Oncology



Research group

  • Human Movement: health and rehabilitation


  • ISSN: 0284-186X