title: Job strain and risk of breast cancer.
abstract: BACKGROUND
  Cohort studies investigating the association between stress and breast cancer have shown highly inconsistent results.
  
  
  METHODS
  The Women's Lifestyle and Health Cohort Study included 36,332 Swedish women age 30-50 years who were employed at baseline (1991-1992). Participants were followed through December 2004 using linkages to national registries. A total of 767 women were diagnosed with breast cancer during follow-up.
  
  
  RESULTS
  Among women working full-time, low job control and high job demands were weakly associated with breast cancer risk (hazard ratios of 1.2; 95% CI = 1.0-1.5). Women with both low job control and high job demands ("job strain") had higher risk of breast cancer than women with high job control and low demands ("low strain") (1.2; 0.9-1.6). Multivariate adjustment slightly strengthened the association between breast cancer and job strain (1.4; 1.1-1.9), whereas the associations with control and demands were unchanged. Work characteristics were unrelated to breast cancer risk among women working part-time.
  
  
  CONCLUSIONS
  There was a small increased risk of breast cancer among women in full-time employment who experienced job strain, but not among part-time workers.
authors.affiliation: Clinical Research Unit, London School of Hygiene and Tropical Medicine, London, UK. hannah.kuper@lshtm.ac.uk
authors.forename: Hannah
authors.initials: H
authors.lastname: Kuper
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Tores
authors.initials: T
authors.lastname: Theorell
authors.forename: Elisabete
authors.initials: E
authors.lastname: Weiderpass
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D016273:Occupational Exposure; D018570:Risk Assessment; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology