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Meta-Analysis
. 2013 Oct;98(4):1020-31.
doi: 10.3945/ajcn.113.062794. Epub 2013 Aug 21.

Breastfeeding and ovarian cancer risk: a meta-analysis of epidemiologic studies

Nan-Nan Luan  1 , Qi-Jun Wu, Ting-Ting Gong, Emily Vogtmann, Yong-Lai Wang, Bei Lin
Affiliations
Meta-Analysis

Breastfeeding and ovarian cancer risk: a meta-analysis of epidemiologic studies

Nan-Nan Luan et al. Am J Clin Nutr. 2013 Oct.

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.

Design: 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.

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Figures

FIGURE 1.
FIGURE 1.
Selection of studies for inclusion in the meta-analysis.
FIGURE 2.
FIGURE 2.
Forest plot (random-effects model) of ever breastfeeding and ovarian cancer risk. Squares indicate study-specific RRs (the size of the square reflects the study-specific statistical weight); horizontal lines indicate 95% CIs; the diamond indicates the summary RR estimate with its 95% CI.
FIGURE 3.
FIGURE 3.
Forest plot (random-effects model) of the total duration of breastfeeding (dose-response analyses on the basis of increases of 5 mo in duration) and ovarian cancer risk. Squares indicate study-specific RRs (the size of the square reflects the study-specific statistical weight); horizontal lines indicate 95% CIs; the diamond indicates the summary RR estimate with its 95% CI.
See this image and copyright information in PMC

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