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Recreational physical activity and risk of postmenopausal breast cancer based on hormone receptor status.
Arch Intern Med 2006 Dec 11-25; 166(22):2478-83AI

Abstract

BACKGROUND

Physical activity is a potentially modifiable breast cancer risk factor. There is considerable recent evidence to suggest that risk factors for breast cancer differ based on its subtype, particularly estrogen receptor (ER)/progesterone receptor (PR) status, but this has been less well studied for physical activity. The objective of this study was to examine the association of physical activity with breast cancer incidence based on ER/PR status of the tumor.

METHODS

The Iowa Women's Health Study is a prospective cohort study of 41 836 postmenopausal women. Recreational physical activity was self-reported on the baseline questionnaire, and 3 levels (high, medium, and low) were defined. Breast cancer incidence and ER/PR status, through 18 years of follow-up, were ascertained by linkage with the Iowa Surveillance, Epidemiology, and End Results Cancer Registry. Cox proportional hazards models were used to estimate multivariate relative risks (RRs) and 95% confidence intervals (CIs) of breast cancer, adjusting for other breast cancer risk factors.

RESULTS

During 554 819 person-years of follow-up, 2548 incident cases of breast cancer were observed. Compared with low physical activity, high physical activity levels were inversely associated with risk of breast cancer (RR, 0.86; 95% CI, 0.78-0.96), and there were inverse associations for ER-positive (ER+)/PR-positive (RR, 0.87; 95% CI, 0.75-1.00), ER+/PR-negative (PR-) (RR, 0.67; 95% CI, 0.47-0.96), and ER-negative/PR- (RR, 0.80; 95% CI, 0.56-1.14) tumors. Further adjustment for body mass index attenuated the overall association with breast cancer (RR, 0.91; 95% CI, 0.82-1.01) and for ER+/PR-positive tumors (RR, 0.94; 95% CI, 0.81-1.08), while there was no change for ER+/PR- tumors (RR, 0.66; 95% CI, 0.46-0.94).

CONCLUSIONS

Higher recreational physical activity might reduce the risk of postmenopausal breast cancer overall. Risk reduction varies by ER/PR status of the tumor, being most marked for ER+/PR- tumors, which, in general, have been associated with a clinically more aggressive tumor phenotype. If confirmed in additional studies, these results would suggest that additional mechanisms, besides an effect on body mass, may account for observed protective effects of physical activity in reducing breast cancer.

Authors+Show Affiliations

Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.No 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

17159013

Citation

Bardia, Aditya, et al. "Recreational Physical Activity and Risk of Postmenopausal Breast Cancer Based On Hormone Receptor Status." Archives of Internal Medicine, vol. 166, no. 22, 2006, pp. 2478-83.
Bardia A, Hartmann LC, Vachon CM, et al. Recreational physical activity and risk of postmenopausal breast cancer based on hormone receptor status. Arch Intern Med. 2006;166(22):2478-83.
Bardia, A., Hartmann, L. C., Vachon, C. M., Vierkant, R. A., Wang, A. H., Olson, J. E., ... Cerhan, J. R. (2006). Recreational physical activity and risk of postmenopausal breast cancer based on hormone receptor status. Archives of Internal Medicine, 166(22), pp. 2478-83.
Bardia A, et al. Recreational Physical Activity and Risk of Postmenopausal Breast Cancer Based On Hormone Receptor Status. Arch Intern Med. 2006;166(22):2478-83. PubMed PMID: 17159013.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Recreational physical activity and risk of postmenopausal breast cancer based on hormone receptor status. AU - Bardia,Aditya, AU - Hartmann,Lynn C, AU - Vachon,Celine M, AU - Vierkant,Robert A, AU - Wang,Alice H, AU - Olson,Janet E, AU - Sellers,Thomas A, AU - Cerhan,James R, PY - 2006/12/13/pubmed PY - 2007/1/17/medline PY - 2006/12/13/entrez SP - 2478 EP - 83 JF - Archives of internal medicine JO - Arch. Intern. Med. VL - 166 IS - 22 N2 - BACKGROUND: Physical activity is a potentially modifiable breast cancer risk factor. There is considerable recent evidence to suggest that risk factors for breast cancer differ based on its subtype, particularly estrogen receptor (ER)/progesterone receptor (PR) status, but this has been less well studied for physical activity. The objective of this study was to examine the association of physical activity with breast cancer incidence based on ER/PR status of the tumor. METHODS: The Iowa Women's Health Study is a prospective cohort study of 41 836 postmenopausal women. Recreational physical activity was self-reported on the baseline questionnaire, and 3 levels (high, medium, and low) were defined. Breast cancer incidence and ER/PR status, through 18 years of follow-up, were ascertained by linkage with the Iowa Surveillance, Epidemiology, and End Results Cancer Registry. Cox proportional hazards models were used to estimate multivariate relative risks (RRs) and 95% confidence intervals (CIs) of breast cancer, adjusting for other breast cancer risk factors. RESULTS: During 554 819 person-years of follow-up, 2548 incident cases of breast cancer were observed. Compared with low physical activity, high physical activity levels were inversely associated with risk of breast cancer (RR, 0.86; 95% CI, 0.78-0.96), and there were inverse associations for ER-positive (ER+)/PR-positive (RR, 0.87; 95% CI, 0.75-1.00), ER+/PR-negative (PR-) (RR, 0.67; 95% CI, 0.47-0.96), and ER-negative/PR- (RR, 0.80; 95% CI, 0.56-1.14) tumors. Further adjustment for body mass index attenuated the overall association with breast cancer (RR, 0.91; 95% CI, 0.82-1.01) and for ER+/PR-positive tumors (RR, 0.94; 95% CI, 0.81-1.08), while there was no change for ER+/PR- tumors (RR, 0.66; 95% CI, 0.46-0.94). CONCLUSIONS: Higher recreational physical activity might reduce the risk of postmenopausal breast cancer overall. Risk reduction varies by ER/PR status of the tumor, being most marked for ER+/PR- tumors, which, in general, have been associated with a clinically more aggressive tumor phenotype. If confirmed in additional studies, these results would suggest that additional mechanisms, besides an effect on body mass, may account for observed protective effects of physical activity in reducing breast cancer. SN - 0003-9926 UR - https://www.unboundmedicine.com/medline/citation/17159013/Recreational_physical_activity_and_risk_of_postmenopausal_breast_cancer_based_on_hormone_receptor_status_ L2 - https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/10.1001/archinte.166.22.2478 DB - PRIME DP - Unbound Medicine ER -