Table 5.

History of hot flushes and risk of breast cancer by histologic type

Hot flushesControls (n = 449)Ductal cases (n = 494)Lobular cases (n = 307)Ductal-lobular cases (n = 187)
n (%)n (%)ORc (95% CI)n (%)ORc (95% CI)n (%)ORc (95% CI)
Never had menopausal symptoms51 (11.4)96 (19.4)1.0 (ref)56 (18.2)1.0 (ref)25 (13.4)1.0 (ref)
Experienced menopausal symptoms, but never hot flushes55 (12.2)61 (12.3)0.5 (0.3–0.9)b45 (14.7)0.7 (0.4–1.2)27 (14.4)0.9 (0.4–2.0)
Ever experienced hot flushesa343 (76.4)337 (68.2)0.5 (0.3–0.7)b206 (67.1)0.5 (0.3–0.7)†135 (72.2)0.7 (0.4–1.2)
Ever had hot flushes without perspiration or awakening39 (100)51 (100)0.6 (0.3–1.1)36 (100)0.8 (0.4–1.5)31 (100)1.5 (0.7–3.2)
 Duration of hot flushes without perspiration or awakening (months)d
 <1217 (43.6)21 (41.2)0.5 (0.2–1.1)15 (41.7)0.6 (0.3–1.6)10 (32.3)1.0 (0.3–3.0)
 ≥1222 (56.4)30 (58.8)0.7 (0.3–1.3)21 (58.3)0.9 (0.4–2.0)21 (67.7)1.8 (0.7–4.2)
Ever had hot flushes with perspiration, but not awakening132 (100)147 (100)0.5 (0.3–0.8)c72 (100)0.4 (0.3–0.7)c56 (100)0.7 (0.3–1.3)
 Duration of hot flushes with perspiration but not awakening (months)d
 <1248 (36.4)57 (38.8)0.6 (0.3–1.0)c29 (40.3)0.4 (0.2–0.8)c20 (35.7)0.6 (0.3–1.3)
 12–3543 (32.6)48 (32.6)0.5 (0.3–0.9)c21 (29.2)0.4 (0.2–0.8)c18 (32.2)0.6 (0.3–1.4)
 ≥3641 (31.0)42 (28.6)0.5 (0.3–0.9)c22 (30.5)0.5 (0.3–1.0)c18 (32.1)0.8 (0.3–1.8)
Ever had hot flushes with awakening147 (100)114 (100)0.4 (0.2–0.6)c79 (100)0.3 (0.2–0.6)c40 (100)0.5 (0.3–1.1)
Duration of hot flushes with awakening (months)d
 <1234 (23.1)36 (31.6)0.5 (0.3–0.9)c25 (31.6)0.5 (0.2–1.0)c13 (32.5)0.8 (0.3–2.1)
 12–3556 (38.1)32 (28.1)0.3 (0.2–0.5)c22 (27.8)0.2 (0.1–0.5)c15 (37.5)0.5 (0.2–1.2)
 ≥3657 (38.8)46 (40.3)0.4 (0.2–0.6)c32 (40.6)0.3 (0.2–0.7)c12 (30.0)0.4 (0.2–1.0)
P for trend in hot flash intensityf0.0070.017<0.001
  • aTwenty-five controls, 25 IDC, 19 ILC, and 8 IDLC cases who experienced hot flushes had missing data on the intensity of hot flushes.

  • bP < 0.05.

  • cOR are adjusted for age, year, duration of HT use, and the type of menopause.

  • eAll P values for trend in duration of hot flushes were more than 0.05.

  • fP value for trend across the 3 categories of hot flush intensity.