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Article first published online: 7 JUN 2004
Published 2004 by the American Cancer Society
Volume 101, Issue 2, pages 353–362, 15 July 2004
How to Cite
Ursin, G., Bernstein, L., Wang, Y., Lord, S. J., Deapen, D., Liff, J. M., Norman, S. A., Weiss, L. K., Daling, J. R., Marchbanks, P. A., Malone, K. E., Folger, S. G., McDonald, J. A., Burkman, R. T., Simon, M. S., Strom, B. L. and Spirtas, R. (2004), Reproductive factors and risk of breast carcinoma in a study of white and African-American women. Cancer, 101: 353–362. doi: 10.1002/cncr.20373
This article is a US Government work and, as such, is in the public domain in the United States of America.
The views expressed herein do not necessarily reflect the views of the National Institutes of Health or the U.S. Government.
- Issue published online: 2 JUL 2004
- Article first published online: 7 JUN 2004
- Manuscript Accepted: 20 APR 2004
- Manuscript Revised: 13 APR 2004
- Manuscript Received: 13 JAN 2004
- National Institute of Child Health and Human Development through contracts with Emory University. Grant Number: N01 HD 3-3168
- Fred Hutchinson Cancer Research Center. Grant Number: N01 HD 2-3166
- Karmanos Cancer Institute at Wayne State University. Grant Number: N01 HD 3-3174
- The University of Pennsylvania. Grant Number: N01 HD-3-3176
- The University of Southern California. Grant Number: N01 HD 3-3175
- Centers for Disease Control and Prevention. Grant Number: Y01 HD 7022
- National Cancer Institute Surveillance, Epidemiology, and End Results. Grant Numbers: N01-PC-67006, N01-CN-65064, N01-CN-67010, N01-CN-0532
- reproductive factors;
- breast carcinoma;
- white women;
- African-American women
Few studies have investigated the association between reproductive factors and the risk of breast carcinoma among African-American women. The authors assessed whether the number of full-term pregnancies, age at first full-term pregnancy, and total duration of breastfeeding were associated with similar relative risk estimates in white and African-American women in a large multicenter, population-based case–control study of breast carcinoma.
Case patients were 4567 women (2950 white women and 1617 African-American women) ages 35–64 years with newly diagnosed invasive breast carcinoma between 1994 and 1998. Control patients were 4668 women (3012 white women and 1656 African-American women) who were identified by random-digit dialing and were frequency matched to case patients according to study center, race, and age. Adjusted odds ratios and 95% confidence intervals were estimated using unconditional logistic regression.
For white women, the reduction in risk of breast carcinoma per full-term pregnancy was 13% among younger women (ages 35–49 years) and 10% among older women (ages 50–64 years). The corresponding risk reductions for African-American women were 10% and 6%, respectively. Risk decreased significantly with increasing number of full-term pregnancies for both races and both age categories. Duration of lactation was inversely associated with breast carcinoma risk among younger parous white (trend P = 0.0001) and African-American (trend P = 0.01) women. African-American women tended to have more children compared with white women, but parity rates were lower in younger women than in older women in both racial groups. However, breastfeeding was substantially more common in young white women than in young African-American women.
Overall, parity and lactation had similar effects on breast carcinoma risk in white and African-American women. If younger African-American women now are giving birth to fewer children than in the past, without a substantial increase in breastfeeding, breast carcinoma rates may continue to increase at a more rapid rate among these women compared with white women. Cancer 2004. Published 2004 by the American Cancer Society.