title: The metabolic syndrome and cancer: Is the metabolic syndrome useful for predicting cancer risk above and beyond its individual components?
abstract: OBJECTIVE
  The metabolic syndrome (MetS) is a risk factor for cancer. However, it is not known if the MetS confers a greater cancer risk than the sum of its individual components, which components drive the association, or if the MetS predicts future cancer risk.
  
  
  METHODS
  We linked 20,648 participants from the Australian and New Zealand Diabetes and Cancer Collaboration with complete data on the MetS to national cancer registries and used Cox proportional hazards models to estimate associations of the MetS, the number of positive MetS components, and each of the five MetS components separately with the risk for overall, colorectal, prostate and breast cancer. Hazard ratios (HR) and 95% confidence intervals (95%CI) are reported. We assessed predictive ability of the MetS using Harrell's c-statistic.
  
  
  RESULTS
  The MetS was inversely associated with prostate cancer (HR 0.85; 95% CI 0.72-0.99). We found no evidence of an association between the MetS overall, colorectal and breast cancers. For those with five positive MetS components the HR was 1.12 (1.02-1.48) and 2.07 (1.26-3.39) for overall, and colorectal cancer, respectively, compared with those with zero positive MetS components. Greater waist circumference (WC) (1.38; 1.13-1.70) and elevated blood pressure (1.29; 1.01-1.64) were associated with colorectal cancer. Elevated WC and triglycerides were (inversely) associated with prostate cancer. MetS models were only poor to moderate discriminators for all cancer outcomes.
  
  
  CONCLUSIONS
  We show that the MetS is (inversely) associated with prostate cancer, but is not associated with overall, colorectal or breast cancer. Although, persons with five positive components of the MetS are at a 1.2 and 2.1 increased risk for overall and colorectal cancer, respectively, and these associations appear to be driven, largely, by elevated WC and BP. We also demonstrate that the MetS is only a moderate discriminator of cancer risk.
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia. Electronic address: jessica.harding@bakeridi.edu.au.
authors.forename: J
authors.initials: J
authors.lastname: Harding
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Sooriyakumaran
authors.affiliation: Research School of Population Health, the Australian National University, Canberra, Australia.
authors.forename: K J
authors.initials: KJ
authors.lastname: Anstey
authors.affiliation: The Health Observatory Discipline of Medicine, the University of Adelaide, Adelaide, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Adams
authors.affiliation: Inserm, U1018, Centre for Research in Epidemiology and Population Health, France.
authors.forename: B
authors.initials: B
authors.lastname: Balkau
authors.affiliation: School of Population Health, the University of Western Australia, Crawley, Australia.
authors.forename: T
authors.initials: T
authors.lastname: Briffa
authors.affiliation: School of Medicine and Pharmacology, the University of Western Australia, Fremantle, Australia.
authors.forename: T M E
authors.initials: TM
authors.lastname: Davis
authors.affiliation: School of Medicine and Pharmacology, the University of Western Australia, Fremantle, Australia.
authors.forename: W A
authors.initials: WA
authors.lastname: Davis
authors.affiliation: School of Population Health, the University of Queensland, Brisbane, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Dobson
authors.affiliation: Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; Cancer Epidemiology Centre, the Cancer Council Victoria, Melbourne, Australia; Centre for Epidemiology and Biostatistics, School of Population and Global Heath, the University of Melbourne, Melbourne, Australia.
authors.forename: G G
authors.initials: GG
authors.lastname: Giles
authors.affiliation: Population Research & Outcome Studies, the University of Adelaide, Adelaide, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Grant
authors.affiliation: School of Population Health, the University of Western Australia, Crawley, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Knuiman
authors.affiliation: Flinders Centre for Ageing Studies, Flinders University, Adelaide, Australia.
authors.forename: M
authors.initials: M
authors.lastname: Luszcz
authors.affiliation: Westmead Millennium Institute, the University of Sydney, Sydney, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Mitchell
authors.affiliation: IMPACT Strategic Research Centre School of Medicine, Deakin University, Geelong, Australia; NorthWest Academic Centre, Department of Medicine, the University of Melbourne, St Albans, Australia.
authors.forename: J A
authors.initials: JA
authors.lastname: Pasco
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Reid
authors.affiliation: School of Medicine, University of Western Sydney, Campbelltown, Australia; Department of Rural Health, the University of Melbourne, Shepparton, Australia.
authors.forename: D
authors.initials: D
authors.lastname: Simmons
authors.affiliation: UNSW Australia Lipid Research Dept, St Vincent's Hospital, Sydney, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Simons
authors.affiliation: School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Tonkin
authors.affiliation: The George Institute for Global Health, the University of Sydney, Sydney, Australia; The George Institute for Global Health, Nuffield Department of Population Health, University of Oxford, UK.
authors.forename: M
authors.initials: M
authors.lastname: Woodward
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: J E
authors.initials: JE
authors.lastname: Shaw
authors.affiliation: Department of Clinical Diabetes and Epidemiology, Baker IDI Heart and Diabetes Institute, Melbourne, Australia; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
authors.forename: D J
authors.initials: DJ
authors.lastname: Magliano
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D024821:Metabolic Syndrome / Q000150:complications* / Q000453:epidemiology*; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications* / Q000453:epidemiology*; D012307:Risk Factors
keywords: Cancer; Epidemiology; Metabolic syndrome; Prediction