Risk Reduction of Breast Cancer by Childbirth,Breastfeeding, and Their Interaction in Korean Women: Heterogeneous Effects Across Menopausal Status, Hormone Receptor Status, and Pathological Subtypes

摘要: Objectives The purpose of this study was to examine the associations childbirth, breastfeeding, and their interaction with breast cancer (BC) risk reduction, evaluate heterogeneity in BC reduction effects these factors by menopause, hormone receptor (HR) status, pathological subtype. Methods patients aged 40+ from Korean Breast Cancer Registry 2004-2012 controls Health Examinee cohort participants were included after 1:1 matching (12 889 pairs) age enrollment year. according breast-feeding, calculated logistic regression models using odds ratios (ORs) 95% confidence intervals (CIs). Results decreased childbirth (3+ childbirths relative 1 childbirth: OR, 0.66; CI, 0.56 0.78 0.80; 0.68 0.95 postmenopausal premenopausal women, respectively); degree number children heterogeneous menopausal status (p-heterogeneity=0.04), HR (p-heterogeneity<0.001), subtype (p-heterogeneity<0.001); whereas breastfeeding for 1-12 months showed a association only women (p-heterogeneity<0.05). combination 2 more ≥13 had much stronger 49% (OR, 0.51; 0.45 0.58). Conclusions This suggests that longer reduces strongly, who experience both or breastfeed can reduce about 50%.