title: Impact of overweight and obesity on postmenopausal breast cancer: analysis of 20-year data from Switzerland.
abstract: OBJECTIVE
  Greater body fatness has been identified as a risk factor for postmenopausal breast cancer. For countries with low overweight/obesity rates, data on prevalence and time course of overweight/obesity in women with breast cancer in comparison to women in the general population is limited. The Swiss female population is distinctive for two reasons: (a) low rates of overweight/obesity compared with other western countries, and (b) no obesity epidemic, i.e. stable rates of overweight/obesity for more than 10 years.
  
  
  METHODS
  Overweight and obesity were analyzed in 51 to 80-year-old breast cancer patients initially diagnosed between 1990 and 2009. Patient data was derived from the Basel Breast Cancer Database (BBCD). This data was compared with the data of women of the same age from the four Swiss Health Surveys (SHS) conducted between 1992 and 2007. Differences between measured (BBCD) and self-reported (SHS) data were corrected using equations approved for the Swiss population.
  
  
  RESULTS
  Of 958 postmenopausal BBCD patients, 32% were overweight and 20% were obese. Of the 14,476 women of the SHS, 38% were overweight and 17% were obese. In the BBCD, there was no change in the prevalence of overweight/obesity over the last 20 years. The four SHS show a convex curvature for obesity, i.e. a transient increase. No significant differences were observed between BBCD and corrected SHS data for overweight and obesity during this period.
  
  
  CONCLUSIONS
  In this Swiss study group with a comparably low prevalence of overweight and obesity, no association between body fatness and postmenopausal breast cancer was observed.
authors.affiliation: Institute of Social and Preventive Medicine, University of Zurich, Hirschengraben 84, 8001 Zurich, Switzerland.
authors.forename: Monika
authors.initials: M
authors.lastname: Eichholzer
authors.forename: Seraina Margaretha
authors.initials: SM
authors.lastname: Schmid
authors.forename: Florence
authors.initials: F
authors.lastname: Bovey
authors.forename: Paul
authors.initials: P
authors.lastname: Jordan
authors.forename: Sabine
authors.initials: S
authors.lastname: Rohrmann
authors.forename: Dorothy Jane
authors.initials: DJ
authors.lastname: Huang
authors.forename: Christoph
authors.initials: C
authors.lastname: Rochlitz
authors.forename: Uwe
authors.initials: U
authors.lastname: Güth
mesh_terms: D050154:Adiposity; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology*; D016208:Databases, Factual / Q000706:statistics & numerical data; D005260:Female; D006306:Health Surveys / Q000706:statistics & numerical data; D006801:Humans; D008875:Middle Aged; D050177:Overweight / Q000453:epidemiology*; D015995:Prevalence; D012307:Risk Factors; D013557:Switzerland / Q000453:epidemiology