Cancer Causes & Control

, Volume 9, Issue 2, pp 189–198

Breast cancer in Australian women under the age of 40

  • Margaret R.E. McCredie
  • Gillian S. Dite
  • Graham G. Giles
  • John L. Hopper
Article

DOI: 10.1023/A:1008886328352

Cite this article as:
McCredie, M.R., Dite, G.S., Giles, G.G. et al. Cancer Causes Control (1998) 9: 189. doi:10.1023/A:1008886328352

Abstract

Objectives: A case-control-family study of breast cancer in women under the age of 40 was carried out in Melbourne and Sydney, Australia, from 1992 to 1995 to determine the risk factors for these women. Subjects included 467 incident cases identified by state cancer registries and 408 population-based controls. Methods: All participants completed a structured risk-factor questionnaire and family pedigree during an in-person interview. Where possible, cancers in first- and second-degree relatives were verified. Results: Multiple logistic regression analysis showed that the strongest risk factor for breast cancer was a family history of the disease - having at least one affected first-degree relative trebled the risk (relative risk [RR] = 3.3, 95 percent confidence interval [CI] = 1.9-5.8). Risk increased with height by three percent (standard error [SE] of one percent) per cm, and after adjusting for height, there was evidence for a decreased risk in women weighing 73 kg or more. There was an increased risk of breast cancer after the first full-term birth (RR = 1.8, CI = 1.0-3.5) but this risk fell by 30 percent (SE = 11 percent) with each subsequent livebirth. Conclusions: The effects of other reproductive factors and oral contraceptive use, although not nominally significant, were in accord with published findings from similar studies in young women. This study of Australian women has indicated that some risk factors for breast cancer in women under age 40 differ from those reported for older women either in direction (e.g., weight) or relative importance (e.g., family history).

Age of onset Australia breast cancer family history height oral contraceptives parity weight 

Copyright information

© Chapman and Hall 1998

Authors and Affiliations

  • Margaret R.E. McCredie
    • 1
  • Gillian S. Dite
    • 2
  • Graham G. Giles
    • 3
  • John L. Hopper
    • 2
  1. 1.Cancer Epidemiology Research Unit, New South Wales Cancer Council, Sydney, Australia and the Department of Preventive and Social MedicineUniversity of OtagoDunedinNew Zealand
  2. 2.Genetic Epidemiology Unit, Department of Community MedicineUniversity of MelbourneMelbourneAustralia
  3. 3.Cancer Epidemiology CentreAnti-Cancer Council of Victoria MelbourneAustralia