title: Prediagnostic serum glucose and lipids in relation to survival in breast cancer patients: a competing risk analysis.
abstract: BACKGROUND
  Abnormal glucose and lipids levels may impact survival after breast cancer (BC) diagnosis, but their association to other causes of mortality such as cardiovascular (CV) disease may result in a competing risk problem.
  
  
  METHODS
  We assessed serum glucose, triglycerides (TG) and total cholesterol (TC) measured prospectively 3 months to 3 years before diagnosis in 1798 Swedish women diagnosed with any type of BC between 1985 and 1999. In addition to using Cox regression, we employed latent class proportional hazards models to capture any heterogeneity of associations between these markers and BC death. The latter method was extended to include the primary outcome (BC death) and competing outcomes (CV death and death from other causes), allowing latent class-specific hazard estimation for cause-specific deaths.
  
  
  RESULTS
  A lack of association between prediagnostic glucose, TG or TC with BC death was observed with Cox regression. With latent class proportional hazards model, two latent classes (Class I and II) were suggested. Class I, comprising the majority (81.5 %) of BC patients, had an increased risk of BC death following higher TG levels (HR: 1.87, 95 % CI: 1.01-3.45 for every log TG increase). Lower overall survival was observed in Class II, but no association for BC death was found. On the other hand, TC positively corresponded to CV death in Class II, and similarly, glucose to death from other causes.
  
  
  CONCLUSIONS
  Addressing cohort heterogeneity in relation to BC survival is important in understanding the relationship between metabolic markers and cause-specific death in presence of competing outcomes.
authors.affiliation: Cancer Epidemiology Group, Division of Cancer Studies, King's College London, London, UK. wahyu.wulaningsih@kcl.ac.uk.
authors.forename: Wahyu
authors.initials: W
authors.lastname: Wulaningsih
authors.affiliation: Cancer Epidemiology Group, Division of Cancer Studies, King's College London, London, UK. mariam.vahdaninia@kcl.ac.uk.
authors.forename: Mariam
authors.initials: M
authors.lastname: Vahdaninia
authors.affiliation: Institute for Mathematical and Molecular Biomedicine, King's College London, London, UK. mark.rowley@kcl.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Rowley
authors.affiliation: Cancer Epidemiology Group, Division of Cancer Studies, King's College London, London, UK. lars.holmberg@kcl.ac.uk.|Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden. lars.holmberg@kcl.ac.uk.|Regional Cancer Centre, Uppsala, Sweden. lars.holmberg@kcl.ac.uk.
authors.forename: Lars
authors.initials: L
authors.lastname: Holmberg
authors.affiliation: Cancer Epidemiology Group, Division of Cancer Studies, King's College London, London, UK. hans.garmo@kcl.ac.uk.|Regional Cancer Centre, Uppsala, Sweden. hans.garmo@kcl.ac.uk.
authors.forename: Hans
authors.initials: H
authors.lastname: Garmo
authors.affiliation: Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. hakan.malmstrom@ki.se.
authors.forename: Håkan
authors.initials: H
authors.lastname: Malmstrom
authors.affiliation: Regional Cancer Centre, Uppsala, Sweden. mats.lambe@ki.se.|Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. mats.lambe@ki.se.
authors.forename: Mats
authors.initials: M
authors.lastname: Lambe
authors.affiliation: Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. niklas.hammar@ki.se.|AstraZeneca Sverige, Södertalje, Sweden. niklas.hammar@ki.se.
authors.forename: Niklas
authors.initials: N
authors.lastname: Hammar
authors.affiliation: Department of Cardiovascular Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. goran.walldius@ki.se.
authors.forename: Göran
authors.initials: G
authors.lastname: Walldius
authors.affiliation: Department of Medicine, Clinical Epidemiological Unit, Karolinska Institutet and CALAB Research, Stockholm, Sweden. ingmar.jungner@ki.se.
authors.forename: Ingmar
authors.initials: I
authors.lastname: Jungner
authors.affiliation: Institute for Mathematical and Molecular Biomedicine, King's College London, London, UK. ton.coolen@kcl.ac.uk.
authors.forename: Anthonius C
authors.initials: AC
authors.lastname: Coolen
authors.affiliation: Cancer Epidemiology Group, Division of Cancer Studies, King's College London, London, UK. mieke.vanhemelrijck@kcl.ac.uk.|Department of Epidemiology, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. mieke.vanhemelrijck@kcl.ac.uk.
authors.forename: Mieke
authors.initials: M
authors.lastname: Van Hemelrijck
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose; D001943:Breast Neoplasms / Q000097:blood* / Q000401:mortality* / Q000473:pathology; D002784:Cholesterol / Q000097:blood; D005260:Female; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000401:mortality* / Q000473:pathology; D011379:Prognosis; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D014280:Triglycerides; D002784:Cholesterol