title: Breast cancer incidence in Mongolia.
abstract: OBJECTIVE
  Data on international variation in breast cancer incidence may help to identify additional risk factors. Substantially lower breast cancer rates in Asia than in North America and Western Europe are established, but differences within Asia have been largely ignored despite heterogeneity in lifestyles and environments. Mongolia's breast cancer experience is of interest because of its shared genetics but vastly different diet compared with other parts of Asia.
  
  
  METHODS
  Age-standardized breast cancer incidence and mortality rates obtained from the International Association of Cancer Registries are presented for several Asian countries. Mongolian incidence rates obtained from its cancer registry describe incidence within the country.
  
  
  RESULTS
  Breast cancer incidence in Mongolia (age standardized 8.0/100,000) is almost a third of rates in China (21.6/100,000), and over five times that of Japan (42.7/100,000) and Russia (43.2/100,000). Rates within Mongolia appear to have increased slightly over the last decade and are higher in urban than rural areas (annual percentage increase of age-standardized rates from 1998 to 2005 was 3.60 and 2.57 %, respectively). The increase in breast cancer incidence with age plateaus at menopause, as in other Asian populations.
  
  
  CONCLUSIONS
  Mongolia's low breast cancer incidence is of particular interest because of their unusual diet (primarily red meat and dairy) compared with other Asian countries. More intensive study of potential dietary, reproductive and lifestyle factors in Mongolia with comparison to other Asian populations may provide more clarity in what drives the international breast cancer rate differences.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, MD, USA. troisir@mail.nih.gov
authors.forename: Rebecca
authors.initials: R
authors.lastname: Troisi
authors.forename: Dalkhjav
authors.initials: D
authors.lastname: Altantsetseg
authors.forename: Ganmaa
authors.initials: G
authors.lastname: Davaasambuu
authors.forename: Janet
authors.initials: J
authors.lastname: Rich-Edwards
authors.forename: Dambadarjaa
authors.initials: D
authors.lastname: Davaalkham
authors.forename: Steinar
authors.initials: S
authors.lastname: Tretli
authors.forename: Robert N
authors.initials: RN
authors.lastname: Hoover
authors.forename: A Lindsay
authors.initials: AL
authors.lastname: Frazier
mesh_terms: D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology*; D004032:Diet; D005260:Female; D006801:Humans; D015994:Incidence; D008019:Life Style; D008875:Middle Aged; D008986:Mongolia / Q000453:epidemiology; D012424:Rural Population / Q000706:statistics & numerical data*; D014505:Urban Population / Q000706:statistics & numerical data*; D055815:Young Adult