title: Birth size and breast cancer risk among young California-born women.
abstract: OBJECTIVE
  Evaluate the risk of breast cancer associated with birth size among young California-born women.
  
  
  METHODS
  Invasive breast cancer cases diagnosed 1988-2004 among women born in California during the 1960s were identified from the California Cancer Registry. Breast cancer cases (n = 3,712) were linked to their California birth records. Controls (n = 8,615) were randomly selected from California birth records for women, frequency matched to cases by birth year. Odds ratios (ORs) and 95% confidence intervals (95% CI) were estimated from unconditional logistic regression.
  
  
  RESULTS
  The adjusted OR for breast cancer associated with the highest category of birth weight (≥4,000 g) was 1.12 (95% CI 0.89-1.41), p-trend = 0.02. The adjusted OR for the highest category of birth length (>20 inches) was 1.13 (95% CI 1.02-1.25), p-trend = 0.02. These relationships appeared to be confined to cases with estrogen receptor positive (ER+) tumors (p-trend ≤0.01) or progesterone receptor positive (PR+) tumors (p-trend ≤0.02). No significant associations were found among cases with ER or PR negative tumors.
  
  
  CONCLUSIONS
  Our results confirm previous findings of elevated breast cancer risk associated with increases in birth size. These risks may be confined to ER+ and PR+ tumors, highlighting the potential mechanistic role of sex steroid hormonal pathways.
authors.affiliation: Department of Research, Cancer Prevention Institute of California, 2001 Center Street, Suite 700, Berkeley, CA 94704, USA. susan.hurley@cpic.org
authors.forename: Susan
authors.initials: S
authors.lastname: Hurley
authors.forename: Debbie
authors.initials: D
authors.lastname: Goldberg
authors.forename: Julie
authors.initials: J
authors.lastname: Von Behren
authors.forename: Thu
authors.initials: T
authors.lastname: Quach
authors.forename: Michael
authors.initials: M
authors.lastname: Layefsky
authors.forename: Peggy
authors.initials: P
authors.lastname: Reynolds
mesh_terms: D000328:Adult; D001724:Birth Weight; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000378:metabolism / Q000473:pathology; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008498:Medical Record Linkage; D016017:Odds Ratio; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012306:Risk; D055815:Young Adult
chemical_list: D011960:Receptors, Estrogen; D011980:Receptors, Progesterone