Table 1.

Case-case ORs of tumor characteristics by age among premenopausal cases in the AMBER Consortium

Tumor≥40 years (ref; N = 1,475)<40 years (N = 533)
characteristicN (%)N (%)OR (95% CI)a
Mean age (±SD)46.2 (±4.3)34.7 (±3.8)
 Stage
 Stage I450 (35.8)116 (24.9)1.0
 Stage II572 (45.5)264 (56.8)1.81 (1.34–2.45)
 Stage III/IV234 (18.6)85 (18.3)1.32 (0.90–1.94)
 Missing21968
Subtype
 Luminal A492 (51.4)157 (43.5)1.0
 Luminal B150 (15.7)49 (13.6)1.37 (0.86–2.17)
 HER2+/ER65 (6.8)29 (8.3)1.35 (0.77–2.37)
 Triple-negative250 (26.1)126 (34.9)1.56 (1.09–2.21)
 Missing518172
ER status
 Positive768 (62.1)227 (52.1)1.0
 Negative469 (37.9)209 (47.9)1.35 (1.03–1.77)
 Missing23897
PR status
 Positive699 (56.8)199 (46.2)1.0
 Negative531 (43.2)232 (53.8)1.57 (1.20–2.06)
 Missing245102
HER2 status
 Negative752 (77.5)286 (78.1)1.0
 Positive218 (22.5)80 (21.9)1.15 (0.81–1.65)
 Missing505167
Grade
 Low144 (12.7)33 (8.4)1.0
 Moderate373 (33.0)117 (29.8)2.00 (1.11–3.62)
 High613 (54.2)243 (61.8)2.17 (1.23–3.85)
 Missing345140
Node status
 Negative486 (53.8)175 (51.2)1.0
 Positive418 (46.2)167 (48.8)1.13 (0.87–1.47)
 Missing571191
Tumor size
 ≤2 cm477 (40.2)131 (30.6)1.0
 2–4.9 cm487 (41.0)206 (48.1)1.70 (1.28–2.26)
 ≥5 cm223 (18.8)91 (21.3)1.31 (0.83–2.07)
 Missing288105
  • Abbreviations: ER, estrogen receptor; PR, progesterone receptor.

  • aAdjusted for study site, index year, geographic region, and education status.