BRCA2 and breast cancer: Earlier menarche increased BC risk by 3.49-fold in BRCA2 mutation carriers (95%CI=2.03–6.00) and 3.30-fold in non-carriers with FH (95%CI=1.73–6.34), but was insignificantly associated with BRCA1 carriers and non-carriers for early-onset BC (P-heterogeneity=0.047).