Breastfeeding and the Risk of Ovarian Cancer: A Meta‐Analysis

Introduction The aim of this meta‐analysis was to assess the association between breastfeeding and risk of ovarian cancer. Methods Relevant observational studies were identified by a search of the MEDLINE and EMBASE databases through December 2012. Summary odds ratios (ORs) for ovarian cancer, comparing women who had breastfed with women who had not, were calculated using a random‐effects model. A dose–response meta‐analysis assessed the risk of ovarian cancer by breastfeeding duration. Results A total of 19 studies were included in the meta‐analysis. Compared with women who had not breastfed, women who had breastfed had a significantly decreased risk of ovarian cancer, with an OR of 0.66 (95% CI, 0.57‐0.76; P < .001). We observed an inverse linear relationship with breastfeeding duration: for every one‐month increase in breastfeeding, the OR was 0.98 (95% CI, 0.97‐0.99; P < .001). A nonlinear association was also apparent, with a sharp decrease in the OR when breastfeeding duration was 8 to 10 months. There was evidence of heterogeneity ( I 2 = 83.9%). No publication bias was found (Begg test, P = 0.89; Egger test, P = 0.89). Discussion Breastfeeding reduces the risk of ovarian cancer proportional to duration. Breastfeeding for 8 to 10 months may be most effective for reducing the risk of ovarian cancer. [Correction added to online publication: The article, “Breastfeeding and the Risk of Ovarian Cancer: A Meta‐Analysis,” by L‐P Feng, H‐L Chen, and M‐Y Shen ( J Midwifery Womens Health . 2014;59[4]:428–437. Published online on July 25, 2014.) contains unattributed text on page 436 of the Discussion section from the following article and should have included the appropriate citation: Jordan SJ, Siskind V, Green AC, Whiteman DC, Webb PM. Breastfeeding and the risk of epithelial ovarian cancer. Cancer Causes Control . 2009;21:109–116.]