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Studies on the Abortion-Breast Cancer Link

Research Synthesis: Induced Abortion and Breast Cancer

The numerical risks associated with induced abortion (and its related circumstances, which vary by study) are listed for each study below. The quality of the studies assessing the relationship between induced abortion and breast cancer varies. Many studies concerning breast cancer risk have shown induced abortion to be a risk for breast cancer, in both western and non-western societies. Of the 72 epidemiological studies we have assessed that differentiate induced from spontaneous abortions (or whose data have been re-analyzed to do so), 21 studies show some positive and significant relationship between induced abortion and breast cancer. Seven studies show a positive and marginally significant relationship between the two. Two ecological epidemiological studies have also shown an association between the two.

No. Year Reference OR or RR (95% CI)1) Statistically Significant Positive or Negative Correlation Country or Population
1 1957 M. Segi, I. Fukushima, S. Fujisaku, M. Kurihara, S. Saito, K. Asano, and M. Kamoi, “An Epidemiological Study on Cancer in Japan,” Japanese Journal of Cancer Research (GANN) 48 (Suppl.) (1957): 1-63. 2.63 (1.85-3.75)* Yes Positive Japan
2 1968 H. Watanabe and T. Hirayama, “Epidemiology and Clinical Aspects of Breast Cancer,” Nippon Rinsho 26 (1968): 1843-1849 (in Japanese). 1.51 (0.91-2.53)* No Positive Japan
3 1978 V.V. Dvoirin and A.B. Medvedev, “Role of Women’s Reproductive Status in the Development of Breast Cancer,” in Methods and Progress in Breast Cancer Epidemiology Research, by Tallin (Moscow: Oncology Science Center of the USSR Academy of Sciences, 1978), 53-63 (in Russian). 1.71 (0.80-3.64)* No Positive USSR/ Estonia
4 1979 B. Burany, “Gestational characteristics in women with breast cancer,” Jugosil Ginekol Opstet 19 (1979):237-247 (in Serbo-Croatian). 0.50 (0.33-0.74)* Yes Negative Yugoslavia
5 1981 M.C. Pike, B.E. Henderson, J.T. Casagrande, I. Rosario, and G.E. Gray, “Oral Contraceptive Use and Early Abortion as Risk Factors for Breast Cancer in Young Women,” British Journal of Cancer 43, no. 1 (1981): 72-76. 2.37 (0.85-6.93)* No Positive United States
6 1982 F. Nishiyama, “The Epidemiology of Breast Cancer in Tokushima Prefecture,” Shikoku Ichi 38 (1982): 333-343 (in Japanese). 2.52 (1.99-3.20)* Yes Positive Japan
7 1983 L.A. Brinton, R. Hoover, and J.F. Fraumeni, Jr., “Reproductive factors in the aetiology of breast cancer,” British Journal of Cancer 47, no. 6 (1983): 757-762. 1.34 (.3-5.6) if before first live birth; .89 (.4-2.00) if after first live birth; 5.5 (.8-36.8) if nulliparous No Positive/ Negative/ Positive United States
8 1984 Monique G. Lê, Annie Bacheloti, F. Doyon, A. Kramar, and Catherine Hill, “Oral Contraceptive Use and Breast or Cervical Cancer: Preliminary Results of a French Case-Control Study,” in Hormones and Sexual Factors in Human Cancer Aetiology, eds. J.P Wolff and J.S. Scott (Amsterdam: Elsevier, 1984), 139-147. 1.32 (0.97-1.77)* No Positive France
9 1985 T. Hirohata, T. Shigematsu, A.M. Nomura, Y. Nomura, A. Horie, and I. Hirohata, “Occurrence of breast cancer in relation to diet and reproductive history: a case-control study in Fukuoka, Japan,” National Cancer Institute Monograph 69 (1985): 187-190. 1.52 (0.93-2.48) No Positive Japan
10 1987 C. La Vecchia, A. Decarli, F. Parazzini, A. Gentile, E. Negri, G. Cecchetti, and S. Franceschi, “General epidemiology of breast cancer in northern Italy,” International Journal of Epidemiology16, no. 3 (1987): 347-355. 1.19 (0.82-1.71) if 1 IA; .78 (.52-1.13) if ≥2 IA No Positive/ Negative Italy
11 1988 M. Ewertz and S.W. Duffy, “Risk of breast cancer in relation to reproductive factors in Denmark,” British Journal of Cancer 58, no. 1 (1988): 99-104. 3.85 (1.08-13.6) with IA in nulliparous women Yes Positive Denmark
12 1988 E. Luporsi, “Breast cancer and alcohol,” (PhD thesis, University of Paris-Sud, 1988), data in N. Andrieu, S.W. Duffy, T.E. Rohan, M.G. Lê, E. Luporsi, M. Gerber, R. Renaud, D.G. Zaridze, Y. Lifanova, and N.E. Day, “Familial Risk, Abortion and Their Interactive Effect on the Risk of Breast Cancer—A Combined Analysis of Six Case-Control Studies,” British Journal of Cancer 72, no. 3 (1995): 744-751. 1.8 (1.0-3.5) if 1 IA; 1.9 (.5-6.9) if ≥2 IA Marginal/ No Positive France
13 1988 D.G. Zaridze data (unpublished) in N. Andrieu, S.W. Duffy, T.E. Rohan, M.G. Lê, E. Luporsi, M. Gerber, R. Renaud, D.G. Zaridze, Y. Lifanova, and N.E. Day, “Familial Risk, Abortion and Their Interactive Effect on the Risk of Breast Cancer—A Combined Analysis of Six Case-Control Studies,” British Journal of Cancer 72, no. 3 (1995): 744-751. 1.0 (.7-1.4) if 1 IA; .7 (.6-1.0) if ≥2 IA No/ Marginal Null/ Negative Russia
14 1984 M.G. Lê, A. Bachelot, F. Doyon, A. Kramar, and C. Hill, “Oral Contraceptive Use and Breast Cancer or Cervical Cancer: Preliminary Results of a French Case-Control Study,” in Hormones and Sexual Factors in Human Cancer Aetiology, eds. J-P Wolff and J.D. Scott (Amsterdam: Elsevier Science, 1984), data in N. Andrieu, S.W. Duffy, T.E. Rohan, M.G. Lê, E. Luporsi, M. Gerber, R. Renaud, D.G. Zaridze, Y. Lifanova, and N.E. Day, “Familial Risk, Abortion and Their Interactive Effect on the Risk of Breast Cancer—A Combined Analysis of Six Case-Control Studies,” British Journal of Cancer 72, no. 3 (1995): 744-751. 1.2 (.7-2.1) if 1 IA; 1.9 (1.0-3.6) if ≥2 IA No/ Marginal Positive France
15 1988 T. Rohan, A.J. McMichael, and P.A. Baghurst, “A population-based case-control study of diet and breast cancer in Australia,” American Journal of Epidemiology 128 (1988): 478-489, data in N. Andrieu, S.W. Duffy, T.E. Rohan, M.G. Lê, E. Luporsi, M. Gerber, R. Renaud, D.G. Zaridze, Y. Lifanova, and N.E. Day, “Familial Risk, Abortion and Their Interactive Effect on the Risk of Breast Cancer—A Combined Analysis of Six Case-Control Studies,” British Journal of Cancer 72, no. 3 (1995): 744-751. 2.7 (1.1-6.7) if 1 IA; 2.2 (.4-12.0) if ≥2 IA Yes/ No Positive Australia
16 1988 Lynn Rosenberg, Julie R. Palmer, David W. Kaufman, Brian L. Strom, David Schottenfeld, and Samuel Shapiro, “Breast Cancer in Relation to the Occurrence and Time of Induced and Spontaneous Abortion,” American Journal of Epidemiology 127 (1988): 981-989. 1.2 (.9-1.6) if parous; 1.3 (.8-2.2) if nulliparous No Positive United States
17 1989 B.M. Lindefors Harris, G. Eklund, O. Meirik, L.E. Rutqvist, and K. Wiklund, “Risk of cancer of the breast after legal abortion during first trimester: a Swedish register study,” British Medical Journal 299, no. 6713 (1989): 1430-1432. 0.77 (0.58-0.99) Yes Negative Sweden/ Norway
18 1989 Holly L. Howe, Ruby T. Senie, Helen Bzduch, and Peter Herzfeld, “Early Abortion and Breast Cancer Risk Among Women Under Age 40,” International Journal of Epidemiology 18 (1989): 300-304. 1.9 (1.2-3.0) Yes Positive United States
19 1989 Larissa I. Remennick, “Reproductive Patterns and Cancer Incidence in Women: A Population-Based Correlation Study in the USSR,” International Journal of Epidemiology 18, no. 3 (September 1989): 498-510. data not in the form of OR Yes Positive USSR
20 1990 H.O. Adami, R. Bergström, E. Lund, and O. Meirik, “Absence of association between reproductive variables and the risk of breast cancer in young women in Sweden and Norway,” British Journal of Cancer 62, no 1 (1990): 122-126. 0.8 (0.5-1.1) if 1 IA; 1.3 (0.6-3.0) if ≥ 2 IA No Negative/ Positive Sweden/ Norway
21 1991 Fabio Parazzini, Eva Negri, and Carlo La Vecchia, “Spontaneous and induced abortions and risk of breast cancer,” International Journal of Cancer 48, issue 6 (1991): 816-820. 1.0 (0.8-1.3) if 1 IA; .9 (.7-1.2) if > 2 IA No Null/ Negative Italy
22 1992 Fabio Parazzini, Carlo La Vecchia, Eva Negri, Silvia Franceschi, and Luca Bocciolone, “Menstrual and reproductive factors and breast cancer in women with family history of the disease,” International Journal of Cancer 51, issue 5 (1992): 677-681. 1.0 (.4-2.2) No Null Italy
23 1993 A.E. Laing, F.M. Demenais, R. Williams, G. Kissling, V.W. Chen, and G.E. Bonney, “Breast Cancer Risk Factors in African-American Women: The Howard University Tumor Registry Experience,” Journal of the National Medical Association 85 (1993): 931-939. 4.7 (2.6-8.4) if IA and diagnosed BC ≥ 50 yrs old; if BC 41-49 yrs old, 2.8 (1.0-8.1); if BC ≤40 yrs old, 1.5 (0.7-3.5) Yes/ Marginal/ No Positive United States
24 1993 Carlo La Vecchia, Eva Negri, Silvia Franceschi, Fabio Parazzini, “Long-term impact of reproductive factors on cancer risk,” International Journal of Cancer 53, issue 2 (1993): 215-219. 1.0 if 1 IA, ns; .8 if ≥ 2 IA, p < .05 No/ Yes Null/ Negative Italy
25 1993 Miriam Moseson, Karen L. Koenig, Roy E. Shore, and Bernard S. Pasternack, “The influence of medical conditions associated with hormones on the risk of breast cancer,” International Journal of Epidemiology 22, issue 6 (1993): 1000-1009. 1.0 (0.7-1.4) No Negative United States
26 1994 N. Andrieu, F. Clavel, B. Gairard, L. Piana, A. Bremond, J. Lansac, R. Flamant, and R. Renaud, “Familial risk of breast cancer and abortion,” Cancer Detection and Prevention 18, no. 1 (1994): 51-55. 1.2 (0.8-1.8) if 1 IA; .9 (.5-1.7) if ≥ 2 IA No Positive/ Negative France
27 1994 Janet R. Daling, Kathleen E. Malone, Lynda F. Voigt, Emily White, and Noel S. Weiss, “Risk of Breast Cancer among Young Women: Relationship to Induced Abortions,” Journal of the National Cancer Institute 86 (1994): 1584-1592. 1.5 (1.2-1.9) Yes Positive United States
28 1994 A.E. Laing, G.E. Bonney, L. Adams-Campbell, et al., “Reproductive and Lifestyle Risk Factors for Breast Cancer in African-American Women,” Genetic Epidemiology 11 (1994): A300. 2.44 (1.0-6.0)* Yes Positive United States
29 1995 N. Andrieu, S.W. Duffy, T.E. Rohan, M.G. Lê, E. Luporsi, M. Gerber, R. Renaud, D.G. Zaridze, Y. Lifanova, and N.E. Day, “Familial Risk, Abortion and Their Interactive Effect on the Risk of Breast Cancer—A Combined Analysis of Six Case-Control Studies,” British Journal of Cancer 72, no. 3 (1995): 744-751 1.5 (1.1-1.9) if 1 IA Yes Positive Multinational
30 1995 Louise A. Brinton, Janet R. Daling Jr., Jonathan M. Liff, Janet B. Schoenberg, Kathleen E. Malone, Janet L. Stanford, Ralph J. Coates, Marilie D. Gammon, Louise Hanson, and Robert N. Hoover, “Oral contraceptives and breast cancer risk among younger women,” Journal of the National Cancer Institute 87 (1995): 827-835. 0.98 (0.8-1.2) 1 IA; 1.02 (0.8-1.4) if ≥ 2 IA No Negative/ Positive United States
31 1995 L. Bu, L.F. Voigt, Z. Yu, K.E. Malone, and J.R. Daling, “Risk of breast cancer associated with induced abortion in a population at low risk of breast cancer,” American Journal of Epidemiology 141 (1995): S85 (abstract 337). 2.9 (1.9-4.4) if 1 IA; 3.6 (2.2-6.0) if ≤ 2 IA; 4.5 (1.9-10.7) if BC ≤ 35 yrs old Yes Positive China
32 1995 Loren Lipworth, Klea Katsouyanni, Anders Ekbom, Karin B. Michels, and Dimitrios Trichopoulos, “Abortion and the Risk of Breast Cancer: A Case-Control Study in Greece,” International Journal of Cancer 61 (1995): 181-184. 1.51 (1.24-1.84); 2.06 (1.45-2.9) if IA before FFTP among parous women Yes Positive Greece
33 1996 Janet R. Daling, Louise A. Brinton, Lynda F. Voigt, Noel S. Weiss, Ralph J. Crates, Kathleen E. Malone, Janet B. Schoenberg, and Marilie Gammon, “Risk of Breast Cancer among White Women Following Induced Abortion,” American Journal of Epidemiology 144 (1996): 373-380. 1.3 (1.0-1.6) if 1 IA Marginal Positive United States
34 1996 Polly A. Newcomb, Barry E. Storer, Matthew P. Longnecker, Robert Mittendorf, E. Robert Greenberg, and Walter C. Willett, “Pregnancy Termination in Relation to Risk of Breast Cancer,” Journal of the American Medical Association 275 (1996): 283-287. 1.23 (1.0-1.51) Marginal Positive United States
35 1996 Matti A. Rookus and Flora E. van Leeuwen, “Induced Abortion and Risk for Breast Cancer: Reporting (Recall) Bias in a Dutch Case-Control Study,” Journal of the National Cancer Institute 88 (1996): 1759-1764. 1.9 (1.1-3.2); if before first birth, 2.6 (1.0-6.8) Yes/ Marginal Positive Netherlands
36 1996 R. Talamini, S. Franceschi, C. La Vecchia, E. Negri, L. Borsa, M. Montella, F. Falcini, E. Conti, and C. Rossi, “The Role of Reproductive and Menstrual Factors in Cancer of the Breast Before and After Menopause,” European Journal of Cancer 32A, no. 2 (1996): 303-310. 1.2 (1.0-1.5) if 1 IA Marginal Positive Italy
37 1996 A. Tavani, C. La Vecchia, S. Franceschi, E. Negri, B. D’avanao, A. Decarli, “Abortion and breast cancer risk,” International Journal of Cancer 65 (1996): 401-405. 1.2 (1.0-1.5) Marginal Positive Italy
38 1996 A.H. Wu, R.G. Ziegler, M.C. Pike, A.M. Nomura, D.W. West, L.N. Kolonel, P.L. Horn-Ross, J.F. Rosenthal, and R.N. Hoover, “Menstrual and reproductive factors and risk of breast cancer in Asian-Americans,” British Journal of Cancer 73, no. 5 (1996): 680-686. 1.92 (0.7-5.3) if nulliparous and had only IAs No Positive United States
39 1997 Mads Melbye, Jan Wohlfahrt, Jørgen H. Olsen, Morten Frisch, Tine Westergaard, Karin Helweg-Larsen, and Per Kragh Andersen, “Induced Abortion and the Risk of Breast Cancer,” New England Journal of Medicine 336, no. 2 (1997): 81-85. 1.00 (.94-1.06) No Null Denmark
40 1997 Julie R. Palmer, Lynn Rosenberg, R. Sowmya Rao, Ann Zauber, Brian L. Strom, M. Ellen Warshauer, Paul D. Stolley, and Samuel Shapiro, “Induced and Spontaneous Abortion in Relation to Risk of Breast Cancer (United States),” Cancer Causes and Control 8 (1997): 841-849. 1.3 (.9-1.9) if nulliparous; 1.1 (.9-1.5) if parous; 1.4 (1.0-1.8) if (parous) IA after one birth. No/ Marginal Positive United States
41 1999 F. Fioretti, A. Tavani, C. Bosetti, C. La Vecchia, E. Negri, F. Barbone, R. Talamini, and S. Franceschi, “Risk factors for breast cancer in nulliparous women,” British Journal of Cancer 78, no. 11/12 (1999): 1923-1928. 0.97 (0.64-1.47); if abortion ≥ 30 yrs old, 1.75 (1.03-2.97) No/ Yes Negative/ Positive Italy
42 1999 Pamela M. Marcus, Donna Day Baird, Robert C. Millikan, Patricia G. Moorman, Bahjat Qaqish, and Beth Newman, “Adolescent reproductive events and subsequent breast cancer risk,” American Journal of Public Health 89, no. 8 (1999): 1244-1247. 1.2 (.6-2.7) if first IA < age 20; 1.1 (.7-1.7) if first IA ≥ age 20 No Positive United States
43 2000 DeAnn Lazovich, Julie A. Thompson, Pamela J. Mink, Thomas A. Sellers, and Kristin Anderson, “Induced abortion and breast cancer risk,” Epidemiology 11, no. 1 (2000): 76-80. 1.1 (0.8-1.6); if IA nulliparous, 1.7 (0.6-5.4) No Negative United States
44 2000 P.A. Newcomb and M.T. Mandelson, “A record-based evaluation of induced abortion and breast cancer risk,” Cancer Causes and Control 11, no. 9 (2000): 777-781. 0.9 (0.5-1.6) No Negative United States
45 2000 M.T. Tang, N.S. Weiss, K.E. Malone, “Induced abortion in relation to breast cancer among parous women: A birth certificate registry study,” Epidemiology 11, no. 2 (2000): 177-180. 0.9 (0.7-1.2) if parous No Negative United States
46 2001 M.J. Goldacre, L.M. Kurina, V. Seagroatt, and D. Yeates, “Abortion and Breast Cancer: A Case-Control Record Linkage Study,” Journal of Epidemiology and Community Health 55, no. 5 (2001): 336-337. 0.83 (0.74-0.93) (observed v. expected BC cases) Yes Negative Britain
47 2001 C. Robertson, M. Van Den Donk, M. Primic-Zakelj, T. MacFarlane, and P. Boyle, “The association between induced and spontaneous abortion and risk of breast cancer in Slovenian women aged 25-54,” Breast 10 (2001): 291-298. 2.71 (0.72-10.26) if IA nulliparous; 1.29 (.77-2.17) if uniparous No Positive Slovenia
48 2001 M. Sanderson, X.O. Shu, F. Jin, Q. Dai, W. Wen, Y. Hua, Y.T. Gao, and W. Zheng, “Abortion history and breast cancer risk: Results from the Shanghai Breast Cancer Study,” International Journal of Cancer 96, no. 6 (2001): 899-905. 1.0 (0.8-1.2) if premenopausal BC; .9 (.7-1.2) if postmenopausal BC No Positive China
49 2002 Z. Ye, D.L. Gao, Q. Qin, R.M. Ray, and D.B. Thomas, “Breast cancer in relation to induced abortions in a cohort of Chinese women,” British Journal of Cancer 87, no. 9 (2002): 976. 1.06 (0.84-1.33) No Positive China
50 2003 H. Becher, S. Schmidt, and J. Chang-Claude, “Reproductive factors and familial predisposition for breast cancer by age 50 years. A case-control-family study for assessing main effects and possible gene-environment interaction,” International Journal of Epidemiology 32 (2003): 38-50. 1.35 (1.03-1.78) Yes Positive Germany
51 2003 Gunnar Erlandsson, Scott M. Montgomery, Sven Cnattingius, and Anders Ekbom, “Abortions and breast cancer: record-based case-control study,” International Journal of Cancer 103, no. 5 (2003): 676-679. 0.8 (0.64-1.0) Marginal Negative Sweden
52 2003 M. Mahue-Giangreco, G. Ursin, J. Sullivan-Halley, and L. Bernstein, “Induced abortion, miscarriage, and breast cancer risk of young women,” Cancer Epidemiology, Biomarkers & Prevention 12 (2003): 209-214. 1.05 (0.75-1.48) if parous, 40 or younger; .69 (.46-1.04) if nulliparous, 40 or younger No Positive/ Negative United States
53 2003 Xavier Paoletti, Françoise Clavel-Chapelon, and the E3N group, “Induced and spontaneous abortion and breast cancer risk: results from the E3N cohort study, International Journal of Cancer 106, no. 2 (2003): 270-276. 0.91 (0.82-0.99) Yes Negative France
54 2004 Kathleen Meeske, Michael Press, Alpa Patel, and Leslie Bernstein, “Impact of reproductive factors and lactation on breast carcinomas in situ,” International Journal of Cancer 110 (2004): 103-109. 1.04 (0.56-1.94) if nulliparous; .94 (.6-1.47) if parous, 1 IA No Positive/ Negative United States
55 2004 Julie R. Palmer, Lauren A. Wise, Lucile L. Adams-Campbell, and Lynn Rosenberg, “A prospective study of induced abortion and breast cancer in African-American women,” Cancer Causes & Control 15, no. 2 (2004): 105-111. 1.1 (0.8-1.4) if parous; 0.9 (0.5-1.4) if nulliparous No Positive/ Negative United States
56 2005 David H. Brewster, Diane L. Stockton, Richard Dobbie, Diana Bull, and Valerie Beral, “Risk of Breast Cancer after Miscarriage or Induced Abortion: A Scottish Record Linkage Case-Control Study,” Journal of Epidemiology and Community Health 59, no. 4 (2005): 283-287. 0.8 (0.72-0.89) Yes Negative Scotland
57 2006 G.K. Reeves, et al., “Breast cancer risk in relation to abortion: Results from the EPIC study,” International Journal of Cancer 119, no. 7 (2006): 1741-1745. 0.95 (0.87-1.03) No Negative Europe
58 2006 K.A. Rosenblatt, D.L. Gao, R.M. Ray, M.R. Rowland, Z.C. Nelson, K.J. Wernli, W. Li, and D.B. Thomas, “Induced abortions and the risk of all cancers combined and site-specific cancers in Shanghai,” Cancer Causes and Control 17, no. 10 (2006): 1275-1280. 1.01 (.92-1.12) No Positive China
59 2006 Najmeh Tehranian, M. Amelbaraez, R. Salke, and S. Faghihzadeh, “The effect of abortion on the risk of breast cancer” (Iranian study presented at a conference at McMaster University, 2006). http://hdl.handle.net/10755/163877 7.94 (2.05-26.21) with IA < 12 wks Yes Positive Iran
60 2007 Karin B. Michels, Fei Xue, Graham A. Colditz, and Walter C. Willett, “Induced and Spontaneous Abortion and Incidence of Breast Cancer among Young Women,” Archives of Internal Medicine 167, no.8 (2007): 814-820. 1.01 (0.88-1.17) No Positive United States
61 2007 Kourosh Holakouie Naieni, Ali Ardalan, Mahmood Mahmoodi, Abbas Motevalian, Yoosef Yahyapoor, and Bahareh Yazdizadeh, “Risk Factors of Breast Cancer in North of Iran: A Case-Control in Mazandaran Province,” Asian Pacific Journal of Cancer Prevention 8, no. 3 (2007): 395-398. Available at http://www.apocp.org/cancer_download/Volume8_No3/395-398%20c_Naieni%204.pdf. 1.62 (1.13-2.31) Yes Positive Iran
62 2008 Katherine DeLellis Henderson, Jane Sullivan-Halley, Peggy Reynolds, Pamela L. Horn-Ross, Christina A. Clarke, Ellen T. Chang, Susan Neuhausen, Giske Ursind, and Leslie Bernstein, “Incomplete Pregnancy Is Not Associated with Breast Cancer Risk: the California Teachers Study,” Contraception 77 (2008): 391-396. .95 (.76-1.18) if nulliparous; 1.05 (0.92-1.2) if parous No Negative/ Positive United States
63 2008 Jie Lin and Jian-feng Yu, “A case control study on risk factors of breast cancer among women in Cixi,” Zhejiang Journal of Preventive Medicine 20, no. 6 (June 2008): 3-5. 2.38 (1.09-5.2) Yes Positive China
64 2009 Jessica M. Dolle, Janet R. Daling, Emily White, Louise A. Brinton, David R. Doody, Peggy L. Porter, and Kathleen E. Malone, “Risk Factors for Triple-Negative Breast Cancer in Women Under the Age of 45 Years,” Cancer Epidemiology, Biomarkers and Prevention 18, no. 4 (2009): 1157-1166. 1.4 (1.1-1.8) Yes Positive United States
65 2009 Vahit Ozmen, Beyza Ozcinar, Hasan Karanlik, Neslihan Cabioglu, Mustafa Tukenmez, Rian Disci, Tolga Ozmen, Abdullah Igci, Mahmut Muslumanoglu, Mustafa Kecer, and Atilla Soran, “Breast Cancer Risk Factors in Turkish Women– a University Hospital Based Nested Case Control Study,” World Journal of Surgical Oncology 7, no. 37 (2009). 1.66 (1.39-1.98) Yes Positive Turkey
66 2009 Peng Xing, Jiguang Li and Feng Jin, “A Case-Control Study of Reproductive Factors Associated with Subtypes of Breast Cancer in Northeast China,” Medical Oncology 27, no. 3 (2009): 926-931. 1.26 (1.05-1.52) for luminal A breast cancer Yes Positive China
67 2011 L. Khachatryan, R. Scharpf, and S. Kagan, “Influence of diabetes mellitus type 2 and prolonged estrogen exposure on risk of breast cancer among women in Armenia,” Health Care for Women International 32, no. 11 (2011): 953-971.2.86 (1.02-8.04) Yes Positive Armenia
68 2012 A.R. Jiang, C.M. Gao, J.H. Ding, S.P. Li, Y.T. Liu, H.X. Cao, J.Z. Wu, J.H. Tang, Y. Qian, and K. Tajima, “Abortions and Breast Cancer Risk in Premenopausal and Postmenopausal Women in Jiangsu Province of China,” Asian Pacific Journal of Cancer Prevention 13 (2012): 33-35. 1.52 (1.21-1.92) Yes Positive China
69 2012 Julie Lecarpentier, et al., “Variation in breast cancer risk associated with factors related to pregnancies according to truncating mutation location, in the French National BRCA1 and BRCA2 mutations carrier cohort (GENEPSO),” Breast Cancer Research 14, issue 4 (2012): R99. (hazard ratio) 1.15 (.83-1.6) if 1 IA; 1.77 (1.19-2.63) if IA before FFTP No/ Yes Positive France
70 2013 Christina Marie Braüner, Kim Overvad, Anne Tjønneland, and Jørn Attermann, “Induced abortion and breast cancer among parous women: A Danish cohort study” [published online ahead of print April 13, 2013], Acta Obstetricia et Gynecologica Scandinavica 92, issue 6 (2013): 700-705. .95 (.83-1.09) No Negative Denmark
71 2013 S. Jabeen, M. Haque, J. Islam, M.Z. Hossain, A. Begum, and M.A. Kashem, “Breast Cancer and Some Epidemiological Factors: A Hospital Based Study,” Journal of Dhaka Medical College 22, no. 1 (2013): 61-66. 20.62 No Positive Bangladesh
72 2013 Ramchandra Kamath, Kamaleshwar S. Mahajan, Lena Ashok, T.S. Sanal, “A study on risk factors of bresat cancer among patients attending the tertiary care hospital, in Udupi district,” Indian Journal of Community Medicine 38, no. 2 (2013): 95-99. 6.38 (.99-40.81) No Positive India
1) BC- Breast cancer
IA- Induced abortion
FFTP- First full-term pregnancy
Luminal A cancer- Estrogen positive and HER2 negative
Nulliparous- Has never given birth
Parous- Has given birth
*Odds ratio obtained from 1996 Brind