The Effect of Breastfeeding Duration and Parity on the Risk of Epithelial Ovarian Cancer: A Systematic Review and Meta-analysis

• Main Authors: Ho Kyung Sung (Author), Seung Hyun Ma (Author), Ji-Yeob Choi (Author), Yunji Hwang (Author), Choonghyun Ahn (Author), Byoung-Gie Kim (Author), Yong-Man Kim (Author), Jae Weon Kim (Author), Sokbom Kang (Author), Jaehoon Kim (Author), Tae Jin Kim (Author), Keun-Young Yoo (Author), Daehee Kang (Author), Suekyung Park (Author)
• Format: Book
• Published: Korean Society for Preventive Medicine, 2016-11-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1975-8375; 2233-4521; 10.3961/jpmph.16.066
• Keywords: Ovarian neoplasms; Parity; Breast feeding; Reproduction; Risk factors; Meta-analysis; Medicine; R; Public aspects of medicine; RA1-1270
• Source: Journal of Preventive Medicine and Public Health, Vol 49, Iss 6, Pp 349-366 (2016)

Objectives We conducted a systematic review and meta-analysis to summarize current evidence regarding the association of parity and duration of breastfeeding with the risk of epithelial ovarian cancer (EOC). Methods A systematic search of relevant studies published by December 31, 2015 was performed in PubMed and EMBASE. A random-effect model was used to obtain the summary relative risks (RRs) and 95% confidence intervals (CIs). Results Thirty-two studies had parity categories of 1, 2, and ≥3. The summary RRs for EOC were 0.72 (95% CI, 0.65 to 0.79), 0.57 (95% CI, 0.49 to 0.65), and 0.46 (95% CI, 0.41 to 0.52), respectively. Small to moderate heterogeneity was observed for one birth (p<0.01; Q=59.46; I2=47.9%). Fifteen studies had breastfeeding categories of <6 months, 6-12 months, and >13 months. The summary RRs were 0.79 (95% CI, 0.72 to 0.87), 0.72 (95% CI, 0.64 to 0.81), and 0.67 (95% CI, 0.56 to 0.79), respectively. Only small heterogeneity was observed for <6 months of breastfeeding (p=0.17; Q=18.79, I2=25.5%). Compared to nulliparous women with no history of breastfeeding, the joint effects of two births and <6 months of breastfeeding resulted in a 0.5-fold reduced risk for EOC. Conclusions The first birth and breastfeeding for <6 months were associated with significant reductions in EOC risk.