Basic Science Tower, Stony Brook University, Stony Brook, NY 11794-8651 / 631-444-3219
Medical Scientist (M.D./Ph.D.) Training Program

Tricia M. Peters
B.A. Colgate University, 2003
M.Phil. University of Cambridge (Darwin College), 2006
Ph.D. University of Cambridge (Darwin College), 2009

4th Year Medical Student

Advisors: Michael Leitzmann, M.D., Dr. PH; Nick Wareham, MBBS, Ph.D.;
Ulf Ekelund, Ph.D.

Department: National Cancer Institute; MRC Epidemiology Unit

Graduate Program: Epidemiology

Title:  Physical activity and postmenopausal breast cancer risk in the NIH-AARP Diet and Health study

Preceptor: Dr. Michael Leitzmann, Division of Cancer Epidemiology & Genetics, NIH

Abstract (Ph.D.):

Tricia M. Peters,1,3 Arthur Schatzkin,1 Gretchen L. Gierach,2,5 Steven C. Moore,1 James V. Lacey, Jr.,2 Nicholas J. Wareham,3 Ulf Ekelund,3 Albert R. Hollenbeck,4 and Michael F. Leitzmann6

1Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics,   National Cancer Institute, NIH, Bethesda, MD
2Hormonal and Reproductive Epidemiology Branch, Division of Cancer Epidemiology
  and Genetics, National Cancer Institute, NIH, Bethesda, MD.
3MRC Epidemiology Unit, Institute of Metabolic Science, Cambridge, UK.
4AARP, Washington, DC.
5Cancer Prevention Fellowship Program, Office of Preventive Oncology, National
  Cancer Institute, NIH, DHHS, Bethesda, MD.
6Regensburg University Medical Center, Regensburg, Germany

BACKGROUND: Breast cancer is recognized as the most common cancer affecting U.S. women. Among the few modifiable risk factors for breast cancer, a high versus low level of physical activity has been consistently associated with 20-40% reduced risk of postmenopausal breast cancer. However, it is unclear whether this association varies across breast cancer tumor subtypes or is modified by reproductive and lifestyle factors.

METHODS: We examined the association of physical activity with postmenopausal breast cancer risk in 182,862 U.S. women in the NIH-AARP Diet and Health Study cohort. Physical activity was assessed by self-report at baseline (1995-1996), and 6,609 incident breast cancers were identified through December 31, 2003. Cox regression was used to estimate the relative risk (RR) and 95% confidence intervals (95%CI) of postmenopausal breast cancer overall and by tumor characteristics. Effect modification by select reproductive and lifestyle factors was also explored.

RESULTS: In multivariate models, physical activity was associated with reduced breast cancer risk, and the most active women experienced a 13% lower risk than inactive women (RR=0.87; 95%CI:0.81,0.95). This inverse relationship was not modified by tumor stage or histology, but was suggestively stronger for estrogen receptor (ER)-negative than for ER-positive breast tumors. The relationship was more pronounced among women who had never used menopausal hormone therapy and women with a family history of breast cancer, and also appeared stronger for overweight/obese women.

CONCLUSIONS: A high level of physical activity was associated with reduced postmenopausal breast cancer risk, particular to ER-negative tumors. These results, along with heterogeneity in the physical activity-breast cancer relationship for subgroups of menopausal hormone therapy use, indicate that physical activity likely operates via estrogen-independent and estrogenic mechanisms to influence breast cancer risk.

Publications:
(pre-MSTP publications indicated with an *)

*Peters TM, et al. (on behalf of the InterAct Consortium). Validity of a short questionnaire to assess physical activity in 10 European countries. European Journal of Epidemiology. 2012 Jan; 27(1): 15-25.

*Peters TM, S Brage, K Westgate, et al. The InterAct Consortium: Validity of the short European Prospective Investigation into Cancer and Nutrition (EPIC) Questionnaire to assess physical activity in 10 European countries. In submission.

*Peters TM, XO Shu, SC Moore, et al. (2010). Validity of a physical activity questionnaire in Shanghai. Medicine and Science in Sports and Exercise. 42(12):2222-30.

*Peters TM, SC Moore, YB Xiang, et al. (2010). Accelerometer-measured physical activity in Chinese adults. American Journal of Preventive Medicine, 38(6):583-91.

*Peters TM, A Schatzkin, GL Gierach, SC Moore, JV Lacey Jr, NJ Wareham, U Ekelund, AR Hollenbeck, MF Leitzmann. (2009). Physical activity and postmenopausal breast cancer risk in the NIH-AARP Diet and Health study. CEBP 18(1):289-96.

*Moore SC, TM Peters, J Ahn, et al. (2009). Age-specific physical activity and prostate cancer risk among white men and black men. Cancer. 115(21):5060-70.

*Peters TM, SC Moore, GL Gierach, et al. (2009). Intensity and timing of physical activity in relation to postmenopausal breast cancer risk: the prospective NIH-AARP Diet and Health Study. BMC Cancer, 9:349.

*Moore SC, TM Peters, J Ahn, Y Park, A Schatzkin, D Albanes, R Ballard-Barbash, A Hollenbeck, MF Leitzmann. (2008). Physical activity in relation to total, advanced, and fatal prostate cancer. CEBP. 17(9):2458-66.

*Leitzmann MF, SC Moore, TM Peters, JV Lacey Jr, A Schatzkin, C Schairer, LA Brinton, D Albanes. (2008). Prospective study of physical activity and risk of postmenopausal breast cancer. Cancer Res. 10(5):R92.

*Lipska B, T Peters, TM Hyde, N Halim, C Horowitz, S Mitkus, C Shannon-Weickert, M Matsumoto, A Sawa, R Straub, R Vakkalanka, MM Herman, DR Weinberger, JE Kleinman. (2006). Expression of DISC1 binding partners is reduced in schizophrenia and associated with DISC1 SNPs. Human Molecular Genetics. 15(8):1245-1258.

*Peters TM, U Ekelund, MF Leitzmann, D Easton, R Warren, R Luben, S Bingham, KT Khaw, NJ Wareham. (2007). Physical Activity and Mammographic Breast Density in the EPIC-Norfolk Cohort Study. American Journal of Epidemiology. 167(5):579-585.

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