title: Breastfeeding and ovarian cancer risk: a meta-analysis of epidemiologic studies.
abstract: BACKGROUND
  Epidemiologic studies have yielded inconsistent findings between breastfeeding and epithelial ovarian cancer (EOC) risk.
  
  
  OBJECTIVE
  We performed a meta-analysis to summarize available evidence of the association between breastfeeding and breastfeeding duration and EOC risk from published cohort and case-control studies.
  
  
  METHODS
  Relevant published studies were identified by a search of MEDLINE through December 2012. Two authors (T-TG and Q-JW) independently performed the eligibility evaluation and data abstraction. Study-specific RRs from individual studies were pooled by using a random-effects model, and heterogeneity and publication-bias analyses were conducted.
  
  
  RESULTS
  Five prospective and 30 case-control studies were included in this analysis. The pooled RR for ever compared with never breastfeeding was 0.76 (95% CI: 0.69, 0.83), with moderate heterogeneity (Q = 69.4, P < 0.001, I(2) = 55.3%). Risk of EOC decreased by 8% for every 5-mo increase in the duration of breastfeeding (RR: 0.92; 95% CI: 0.90, 0.95). The risk reduction was similar for borderline and invasive EOC and was consistent within case-control and cohort studies.
  
  
  CONCLUSIONS
  Results of this meta-analysis support the hypothesis that ever breastfeeding and a longer duration of breastfeeding are associated with lower risks of EOC. Additional research is warranted to focus on the association with cancer grade and histologic subtypes of EOC.
authors: Department of Obstetrics and Gynecology, Shengjing Hospital, China Medical University, Shenyang, China and the State Key Laboratory of Oncogene and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
authors: Nan-Nan
authors: NN
authors: Luan
authors: Qi-Jun
authors: QJ
authors: Wu
authors: Ting-Ting
authors: TT
authors: Gong
authors: Emily
authors: E
authors: Vogtmann
authors: Yong-Lai
authors: YL
authors: Wang
authors: Bei
authors: B
authors: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001942:Breast Feeding / Q000706:statistics & numerical data; D000077216:Carcinoma, Ovarian Epithelial; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016239:MEDLINE; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000453:epidemiology* / Q000517:prevention & control; D010051:Ovarian Neoplasms / Q000453:epidemiology* / Q000517:prevention & control; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors
references: J Clin Epidemiol. 1990;43(6):559-68
references: 2348208
references: BMJ. 1997 Sep 13;315(7109):629-34
references: 9310563
references: BMJ. 2009 Jul 21;339:b2535
references: 19622551
references: Gynecol Oncol. 2004 Jan;92(1):320-6
references: 14751177
references: Ann Epidemiol. 2001 Nov;11(8):568-74
references: 11709277
references: Lancet Oncol. 2007 Jan;8(1):26-34
references: 17196508
references: J Womens Health (Larchmt). 2011 Mar;20(3):341-7
references: 21434834
references: J Natl Cancer Inst. 1983 Oct;71(4):711-6
references: 6578366
references: Control Clin Trials. 1986 Sep;7(3):177-88
references: 3802833
references: Epidemiology. 1997 Mar;8(2):188-91
references: 9229212
references: Stat Med. 2002 Jun 15;21(11):1539-58
references: 12111919
references: Am J Epidemiol. 2005 Feb 15;161(4):321-9
references: 15692075
references: Int J Oncol. 2012 Jan;40(1):21-30
references: 21904774
references: Cancer Res. 1988 Oct 15;48(20):5849-52
references: 3167840
references: Br J Cancer. 2011 Oct 25;105(9):1436-42
references: 21915124
references: Br J Cancer. 1989 Oct;60(4):592-8
references: 2679848
references: Int Breastfeed J. 2008 Dec 16;3:29
references: 19087336
references: Int J Epidemiol. 1992 Feb;21(1):23-9
references: 1544753
references: Cancer Causes Control. 2012 Jun;23(6):919-27
references: 22527170
references: JAMA. 1999 Sep 15;282(11):1054-60
references: 10493204
references: Am J Obstet Gynecol. 1989 Jul;161(1):10-6
references: 2750791
references: Am J Epidemiol. 1994 Aug 1;140(3):290-6
references: 8030632
references: Cancer Res. 1999 Aug 1;59(15):3658-62
references: 10446978
references: Gynecol Oncol. 2000 Oct;79(1):50-4
references: 11006030
references: J Natl Cancer Inst. 1983 Oct;71(4):717-21
references: 6578367
references: Biometrics. 1994 Dec;50(4):1088-101
references: 7786990
references: Gynecol Oncol. 2004 Oct;95(1):215-25
references: 15385135
references: Am J Epidemiol. 1983 Feb;117(2):128-39
references: 6681935
references: Lancet. 1971 Jul 17;2(7716):163
references: 4104488
references: Cancer Causes Control. 2010 Feb;21(2):201-7
references: 19902367
references: CA Cancer J Clin. 2012 Jan-Feb;62(1):10-29
references: 22237781
references: Int J Epidemiol. 1993 Apr;22(2):192-7
references: 8505173
references: Gynecol Oncol. 2001 Dec;83(3):575-85
references: 11733975
references: Cancer Epidemiol Biomarkers Prev. 2009 Feb;18(2):601-10
references: 19190154
references: CA Cancer J Clin. 2011 Mar-Apr;61(2):69-90
references: 21296855
references: Am J Epidemiol. 1992 Nov 15;136(10):1212-20
references: 1476143
references: Am J Epidemiol. 2002 Aug 15;156(4):363-73
references: 12181107
references: Am J Epidemiol. 2001 May 1;153(9):860-4
references: 11323316
references: Breast Cancer Res Treat. 2006 Jan;95(2):105-9
references: 16261399
references: Jpn J Cancer Res. 1999 Mar;90(3):255-61
references: 10359038
references: Am J Epidemiol. 2012 Jan 1;175(1):66-73
references: 22135359
references: Int J Cancer. 2013 Jun 15;132(12):2894-900
references: 23175139
references: Acta Paediatr. 2006 Nov;95(11):1370-4
references: 17062462
references: Am J Epidemiol. 1992 Jun 1;135(11):1301-9
references: 1626547
references: JAMA. 2000 Apr 19;283(15):2008-12
references: 10789670
references: Reprod Fertil Dev. 2001;13(7-8):583-90
references: 11999309
references: Breastfeed Med. 2009 Oct;4 Suppl 1:S17-30
references: 19827919
references: Stat Med. 2008 Mar 30;27(7):954-70
references: 17676579
references: Am J Epidemiol. 2004 Dec 1;160(11):1070-8
references: 15561986
references: Cancer Causes Control. 2010 Jan;21(1):109-16
references: 19779839
references: Am J Epidemiol. 2008 May 1;167(9):1059-69
references: 18303003
references: Cancer Causes Control. 2007 Jun;18(5):517-23
references: 17450440
references: Epidemiology. 1996 Jan;7(1):38-45
references: 8664399
references: Jpn J Cancer Res. 1998 Mar;89(3):246-53
references: 9600117
references: Am J Epidemiol. 2000 Aug 1;152(3):233-41
references: 10933270
references: Gynecol Oncol. 2005 Aug;98(2):304-8
references: 15975644
references: Am J Epidemiol. 1988 Oct;128(4):771-7
references: 3421242
references: Am J Epidemiol. 2003 Oct 1;158(7):629-38
references: 14507598
references: Gynecol Oncol. 2003 May;89(2):318-24
references: 12713998
references: Ann Oncol. 2013 Apr;24(4):1079-87
references: 23211939
references: Eur J Cancer Prev. 2004 Dec;13(6):499-502
references: 15548943
references: Cancer Causes Control. 2006 Aug;17(6):821-9
references: 16783610