Details

Autor(en) / Beteiligte

• LORD, Sarah J
• BEMSTEIN, Leslie
• BURKMAN, Ronald T
• DEAPEN, Dennis
• SPIRTAS, Robert
• URSIN, Giske
• JOHNSON, Karen A
• MALONE, Kathleen E
• MCDONALD, Jill A
• MARCHBANKS, Polly A
• SIMON, Michael S
• STROM, Brian L
• PRESS, Michael F
• FOLGER, Suzanne G

Titel

Breast Cancer Risk and Hormone Receptor Status in Older Women by Parity, Age of First Birth, and Breastfeeding: A Case-Control Study

Ist Teil von

• Cancer epidemiology, biomarkers & prevention, 2008-07, Vol.17 (7), p.1723-1730

Ort / Verlag

Philadelphia, PA: American Association for Cancer Research

Erscheinungsjahr

2008

Quelle

MEDLINE

Beschreibungen/Notizen

• Background: Early age at first birth and multiparity reduce the risk of estrogen receptor-progesterone receptor (ERPR)–positive breast cancer, whereas breastfeeding reduces the risk of both ERPR-positive and ERPR-negative cancers. Methods: We used multivariable logistic regression analysis to investigate whether age at first birth (<25 or ≥25 years) and breastfeeding (ever/never) modify the long-term effect of parity on risk of ERPR-positive and ERPR-negative cancer using 1,457 incident breast cancer cases and 1,455 controls ages ≥55 years who participated in the Women's Contraceptive and Reproductive Experiences Study. Results: Women who gave birth before age 25 years had a 36% reduced risk of breast cancer compared with nulligravida that was not observed for women who started their families at an older age ( P heterogeneity = 0.0007). This protective effect was restricted to ERPR-positive breast cancer ( P heterogeneity = 0.004). Late age at first birth increased the risk of ERPR-negative cancers. Additional births reduced the risk of ERPR-positive cancers among women with an early first birth ( P trend = 0.0001) and among women who breastfed ( P trend = 0.004) but not among older mothers or those who never breastfed. In women with a late first birth who never breastfed, multiparity was associated with increased risk of breast cancer. Conclusions: These findings suggest that the effect of parity on a woman's long-term risk of breast cancer is modified by age at first full-term pregnancy and possibly by breastfeeding. (Cancer Epidemiol Biomarkers Prev 2008;17(7):1723–30)