Fig 2. Hazard ratios (HRs) with 95% confidence intervals (CIs) for (A) age at menarche (per 1 year increase) on overall survival (OS) and (B) duration of endogenous estrogen exposure (per 1 year increase), (C) number of children ≥4 vs. 2, and (D) number of years since last birth <5 vs. ≥20 years on disease-free survival (DFS) of breast cancer by intrinsic subtypes.

^aI-squared describes the percentage of the variability in effect estimates that is due to heterogeneity rather than sampling error.