Background: The association between parity and breastfeeding with breast cancer is still conflicting. Therefore, we did an analysis to summarize the recent studies of breast cancer with the subject of parity and breast-feeding.
Materials and methods: The related studies were extracted by a search on PubMed between May 1, 2010 and May 1, 2016. The random-effect model was used. Factors like sensitivity analysis, sub-group analysis, and publication bias were considered.
Results: Twenty-eight papers involving 12,041 breast cancer cases were included in our meta-analysis. The obtained results suggest that breastfeeding was inversely associated with the risk of breast cancer. The association of breastfeeding with in the case of ever breastfeeding compared with never categories were studied. The summary of Odds Ratio for this study was 0.84 (95% Confidence Interval [CI], 0.64-1.32). An inverse association was also found for the longest breastfeeding compared with the shortest categories of breastfeeding with the risk of breast cancer. There is no evidence also for the association of parity and breast cancer in our study.
Conclusion: The results of finding from analysis propose that the number of parities and the longer duration of breastfeeding were inversely associated with the risk of breast cancer.