title: Shift work and chronic disease: the epidemiological evidence.
abstract: BACKGROUND
  Shift work, including night work, has been hypothesized to increase the risk of chronic diseases, including cancer, cardiovascular disease (CVD), metabolic syndrome and diabetes. Recent reviews of evidence relating to these hypotheses have focussed on specific diseases or potential mechanisms, but no general summary of the current data on shift work and chronic disease has been published.
  
  
  METHODS
  Systematic and critical reviews and recent original studies indexed in PubMed prior to 31 December 2009 were retrieved, aided by manual searches of reference lists. The main conclusions from reviews and principle results from recent studies are presented in text and tables.
  
  
  RESULTS
  Published evidence is suggestive but not conclusive for an adverse association between night work and breast cancer but limited and inconsistent for cancers at other sites and all cancers combined. Findings on shift work, in relation to risks of CVD, metabolic syndrome and diabetes are also suggestive but not conclusive for an adverse relationship.
  
  
  CONCLUSIONS
  Heterogeneity of study exposures and outcomes and emphasis on positive but non-significant results make it difficult to draw general conclusions. Further data are needed for additional disease endpoints and study populations.
authors.affiliation: Cancer Epidemiology Unit, University of Oxford, Oxford, UK. xiaosi.wang@ceu.ox.ac.uk
authors.forename: X-S
authors.initials: XS
authors.lastname: Wang
authors.forename: M E G
authors.initials: ME
authors.lastname: Armstrong
authors.forename: B J
authors.initials: BJ
authors.lastname: Cairns
authors.forename: T J
authors.initials: TJ
authors.lastname: Key
authors.forename: R C
authors.initials: RC
authors.lastname: Travis
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D002908:Chronic Disease; D002940:Circadian Rhythm; D015179:Colorectal Neoplasms / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D015201:Meta-Analysis as Topic; D024821:Metabolic Syndrome / Q000453:epidemiology*; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology*; D009784:Occupational Diseases / Q000453:epidemiology*; D010561:Personnel Staffing and Scheduling / Q000706:statistics & numerical data; D011471:Prostatic Neoplasms / Q000453:epidemiology; D012196:Review Literature as Topic; D012307:Risk Factors; D014940:Work Schedule Tolerance