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Reproductive factors and breast cancer risk among older women.
Breast Cancer Res Treat 2007; 102(3):365-74BC

Abstract

Reproductive factors have been shown to affect pre- and postmenopausal breast cancer risk differently, but whether there are additional age-specific differences among menopausal women as they age has not been clarified. We analyzed data from a large population-based case-control study that included 1,508 breast cancer cases and 1,556 controls, aged 20-98 years, who completed an in-home interviewer-administered questionnaire. The following subgroups were created to examine if the associations between reproductive factors and breast cancer risk varied by age- and menopausal-status: premenopausal (n=968), postmenopausal <65 years (n=1,045), postmenopausal >or=65 years (n=958). Among postmenopausal women >or=65 years, ever having breastfed decreased risk (odds ratio (OR)=0.67, 95% confidence interval (CI)=0.48, 0.92), and a strong dose-response relationship was observed for longer durations of breastfeeding (P trend=0.02), with the most pronounced protective effect observed for >or=14 months of breastfeeding (OR=0.40, 95% CI=0.21,0.76). Late age at first birth (AFB) and older age at last birth (ALB) were associated with non-statistically significant increases in breast cancer risk in this older group, while late age at menarche and surgical menopause decreased risk. ORs for multiparity were close to the null. Among premenopausal women and postmenopausal women <65 years, multiparity significantly decreased risk, and older AFB nonsignificantly increased risk. Our findings suggest that the well-known protective effect of multiparity attenuates with older age. Moreover, breastfeeding, one of the few potentially modifiable risk factors for breast cancer, was an important factor in decreasing risk among older parous postmenopausal women.

Authors+Show Affiliations

Department of Epidemiology, CB#7435 McGavran-Greenberg Hall, University of North Carolina School of Public Health, Chapel Hill, NC 27599-7435, USA. sswhite@email.unc.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

17033925

Citation

Shantakumar, Sumitra, et al. "Reproductive Factors and Breast Cancer Risk Among Older Women." Breast Cancer Research and Treatment, vol. 102, no. 3, 2007, pp. 365-74.
Shantakumar S, Terry MB, Teitelbaum SL, et al. Reproductive factors and breast cancer risk among older women. Breast Cancer Res Treat. 2007;102(3):365-74.
Shantakumar, S., Terry, M. B., Teitelbaum, S. L., Britton, J. A., Millikan, R. C., Moorman, P. G., ... Gammon, M. D. (2007). Reproductive factors and breast cancer risk among older women. Breast Cancer Research and Treatment, 102(3), pp. 365-74.
Shantakumar S, et al. Reproductive Factors and Breast Cancer Risk Among Older Women. Breast Cancer Res Treat. 2007;102(3):365-74. PubMed PMID: 17033925.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Reproductive factors and breast cancer risk among older women. AU - Shantakumar,Sumitra, AU - Terry,Mary Beth, AU - Teitelbaum,Susan L, AU - Britton,Julie A, AU - Millikan,Robert C, AU - Moorman,Patricia G, AU - Neugut,Alfred I, AU - Gammon,Marilie D, Y1 - 2006/10/11/ PY - 2006/07/10/received PY - 2006/07/12/accepted PY - 2006/10/13/pubmed PY - 2007/6/22/medline PY - 2006/10/13/entrez SP - 365 EP - 74 JF - Breast cancer research and treatment JO - Breast Cancer Res. Treat. VL - 102 IS - 3 N2 - Reproductive factors have been shown to affect pre- and postmenopausal breast cancer risk differently, but whether there are additional age-specific differences among menopausal women as they age has not been clarified. We analyzed data from a large population-based case-control study that included 1,508 breast cancer cases and 1,556 controls, aged 20-98 years, who completed an in-home interviewer-administered questionnaire. The following subgroups were created to examine if the associations between reproductive factors and breast cancer risk varied by age- and menopausal-status: premenopausal (n=968), postmenopausal <65 years (n=1,045), postmenopausal >or=65 years (n=958). Among postmenopausal women >or=65 years, ever having breastfed decreased risk (odds ratio (OR)=0.67, 95% confidence interval (CI)=0.48, 0.92), and a strong dose-response relationship was observed for longer durations of breastfeeding (P trend=0.02), with the most pronounced protective effect observed for >or=14 months of breastfeeding (OR=0.40, 95% CI=0.21,0.76). Late age at first birth (AFB) and older age at last birth (ALB) were associated with non-statistically significant increases in breast cancer risk in this older group, while late age at menarche and surgical menopause decreased risk. ORs for multiparity were close to the null. Among premenopausal women and postmenopausal women <65 years, multiparity significantly decreased risk, and older AFB nonsignificantly increased risk. Our findings suggest that the well-known protective effect of multiparity attenuates with older age. Moreover, breastfeeding, one of the few potentially modifiable risk factors for breast cancer, was an important factor in decreasing risk among older parous postmenopausal women. SN - 0167-6806 UR - https://www.unboundmedicine.com/medline/citation/17033925/Reproductive_factors_and_breast_cancer_risk_among_older_women_ L2 - https://doi.org/10.1007/s10549-006-9343-4 DB - PRIME DP - Unbound Medicine ER -