Birth Weight as a Risk Factor for Breast Cancer: A Meta-Analysis of 18 Epidemiological Studies Academic Article uri icon


  • BACKGROUND: Birth weight has been identified as a birth-related factor associated with the risk of breast cancer. However, the evidence is inconsistent. METHODS: To investigate the association between birth weight and breast cancer, we conducted a meta-analysis of published studies between 1996 and 2008. Eighteen studies encompassing 16,424 breast cancer cases were included in the meta-analysis. Data were combined using a fixed-effect or random-effect model depending on the heterogeneity across studies. RESULTS: Women with their own birth weight >4000 g or 8.5 lb had a higher risk for developing breast cancer than those with birth weight <2500 g or 3000 g (OR = 1.20, 95% CI 1.08, 1.34). Findings were also consistent with a dose-response pattern effect. The summary effect estimate for breast cancer risk per 1 kg increase in birth weight was statistically significant (random effects OR = 1.07, 95% CI 1.02, 1.12). CONCLUSIONS: Although these results provided no evidence indicating whether birth weight is more strongly related to early-onset than to later-onset breast cancer, our findings suggest an association between birth weight and breast cancer. The underlying biological mechanism relating to this phenomenon needs additional study.

author list (cited authors)

  • Xu, X., Dailey, A. B., Peoples-Sheps, M., Talbott, E. O., Li, N., & Roth, J.

citation count

  • 50

publication date

  • August 2009