A prospective study of induced abortion and breast cancer in African-American women

Cancer Causes Control. 2004 Mar;15(2):105-11. doi: 10.1023/B:CACO.0000019484.29558.f7.


Objective: There continues to be controversy about whether induced abortion influences the risk of breast cancer. Because case-control studies of this relation are subject to recall bias, there is a need for prospective data. Further, there has been little study of abortion and breast cancer in African-American women. We assessed the relation of abortion to risk of breast cancer in a prospective follow-up study of African-American women.

Methods: Black Women's Health Study participants have been followed by mailed questionnaires every two years since enrollment in 1995. Participants reported 348 incident breast cancers during 205,983 person-years of follow-up. Women who had an induced abortion were compared with women who had never had one, with nulliparous and parous women analyzed separately. Incidence rate ratios (IRR) with two-sided 95% confidence intervals (CI) were derived from Cox regression models that controlled for age, age at first birth, number of births, history of spontaneous abortion, and other factors.

Results: Among nulliparous women, the IRR for any induced abortion relative to none was 0.9 (95% CI = 0.5-1.4), and among parous women, the comparable IRR was 1.1 (95% CI = 0.8-1.4). Risk did not vary by number of abortions, age at first abortion, age at diagnosis or a family history of breast cancer in either nulliparous or parous women.

Conclusions: Our findings indicate that induced abortion does not increase breast cancer risk in African-American women.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Abortion, Induced / adverse effects*
  • Abortion, Induced / statistics & numerical data
  • Adolescent
  • Adult
  • African Americans*
  • Aged
  • Breast Neoplasms / ethnology
  • Breast Neoplasms / etiology*
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Middle Aged
  • Multivariate Analysis
  • Parity
  • Prospective Studies
  • Risk Factors
  • United States / epidemiology