title: Metabolic syndrome and the risk of breast cancer in postmenopausal women.
abstract: BACKGROUND
  Only a few small studies investigated the association between postmenopausal breast cancer and metabolic syndrome (MetS) as a single entity.
  
  
  METHODS
  We analyzed the data of two Italian and Swiss case-control studies conducted between 1983 and 2007, including 3869 postmenopausal women with incident breast cancer and 4082 postmenopausal controls admitted to the same hospitals as cases for acute conditions. MetS was defined as the presence of at least three components among diabetes, drug-treated hypertension, drug-treated hyperlipidemia, and obesity.
  
  
  RESULTS
  The odds ratios (ORs) of postmenopausal breast cancer were 1.33 [95% confidence interval (CI) 1.09-1.62] for diabetes, 1.19 (95% CI 1.07-1.33) for hypertension, 1.08 (95% CI 0.95-1.22) for hyperlipidemia, 1.26 (95% CI 1.11-1.44) for body mass index ≥30 kg/m(2), and 1.22 (95% CI 1.09-1.36) for waist circumference ≥88 cm. The risk of postmenopausal breast cancer was significantly increased for women with MetS (OR = 1.75, 95% CI 1.37-2.22, for three or more MetS components, P for trend for increasing number of components < 0.0001) and the risk was higher at older age (OR = 3.04, 95% CI 1.75-5.29, at age ≥70 years for three or more MetS components).
  
  
  CONCLUSIONS
  This study supports a direct association between MetS and postmenopausal breast cancer risk.
authors.affiliation: Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Milan.
authors.forename: V
authors.initials: V
authors.lastname: Rosato
authors.affiliation: Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Milan. Electronic address: cristina.bosetti@marionegri.it.
authors.forename: C
authors.initials: C
authors.lastname: Bosetti
authors.affiliation: Unit of Epidemiology and Biostatistics, Centro di Riferimento Oncologico, IRCCS, Aviano, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Talamini
authors.affiliation: Cancer Epidemiology Unit and Cancer Registry of Vaud, Institute of Social and Preventive Medicine, University of Lausanne, Lausanne, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Levi
authors.affiliation: Department of Epidemiology, Istituto Nazionale Tumori "Fondazione Pascale", Naples.
authors.forename: M
authors.initials: M
authors.lastname: Montella
authors.affiliation: Department of Gastroenterology and Nutrient Unit, Policlinico di Monza, Monza.
authors.forename: A
authors.initials: A
authors.lastname: Giacosa
authors.affiliation: Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Milan.
authors.forename: E
authors.initials: E
authors.lastname: Negri
authors.affiliation: Department of Epidemiology, Istituto di Ricerche Farmacologiche Mario Negri, Milan; Department of Occupational Medicine, Università degli Studi di Milano, Milan, Italy; International Prevention Research Institute, Lyon, France.
authors.forename: C
authors.initials: C
authors.lastname: La Vecchia
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000209:etiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007558:Italy; D016015:Logistic Models; D024821:Metabolic Syndrome / Q000150:complications*; D008875:Middle Aged; D016017:Odds Ratio; D017698:Postmenopause; D012307:Risk Factors; D013557:Switzerland