Table 2.

Adjusteda HRs and 95% CIs for breast cancer recurrence and mortality for levels of isoflavone intake at baseline (all women and stratified by tamoxifen use and hormone receptor status) for women enrolled in WHEL

NNo. of new breast cancer eventsHR (95% CI) for new invasive breast cancer eventb (n = 448)No. of deathsHR (95% CI) for overall mortality(n = 271)
All women (n = 2,736)
Total isoflavones, mg/d
 Level 1 (0–0.07)1,095190Reference: 1133Reference: 1
 Level 2 (0.07–1.01)1,0941670.89 (0.72–1.11)950.75 (0.57–0.99)
 Level 3 (1.01–16.33)410730.99 (0.75–1.32)370.79 (0.54–1.15)
 Level 4 (16.33–86.9)137180.78 (0.46–1.31)60.46 (0.2–1.05)
P for trend = 0.47 P for trend = 0.02
Women who used tamoxifen (n = 1,816)
Total isoflavones, mg/d
 Level 1 (0–0.07)705112Reference: 179Reference: 1
 Level 2 (0.07–1.01)7491060.91 (0.69–1.21)640.79 (0.56–1.12)
 Level 3 (1.01–16.33)274440.97 (0.67–1.41)230.81 (0.5–1.3)
 Level 4 (16.33–86.9)8880.59 (0.27–1.29)20.26 (0.06–1.08)
P for trend = 0.35 P for trend = 0.05
Nonusers of tamoxifen (n = 884)
Isoflavones, mg/d
 Level 1 (0–0.07)37677Reference: 153Reference: 1
 Level 2 (0.07–1.01)334580.82 (0.57–1.17)280.61 (0.38–0.99)
 Level 3 (1.01–16.33)128281.09 (0.69–1.71)130.79 (0.42–1.49)
 Level 4 (16.33–86.9)88100.96 (0.46–1.99)40.68 (0.24–1.99)
P for trend = 1.0 P for trend = 0.20
Interaction between tamoxifen and isoflavones P for interaction = 0.54 P for interaction = 0.45
Women with tumors that were ER+ or PR+ (n = 2,144)
 Level 1 (0–0.07)835137Reference: 193Reference: 1
 Level 2 (0.07–1.01)8651250.9 (0.7–1.16)700.76 (0.55–1.05)
 Level 3 (1.01–16.33)331581.06 (0.77–1.46)300.91 (0.59–1.39)
 Level 4 (16.33–86.9)113140.84 (0.47–1.51)30.31 (0.1–0.98)
P for trend = 0.83 P for trend = 0.07
Women with tumors that were ER/PR (n = 546)
 Level 1 (0–0.07)23850Reference: 138Reference: 1
 Level 2 (0.07–1.01)214390.78 (0.5–1.22)240.62 (0.36–1.07)
 Level 3 (1.01–16.33)74140.79 (0.42–1.49)70.46 (0.19–1.1)
 Level 4 (16.33–86.9]2030.62 (0.19–2.03)30.86 (0.25–2.9)
P for trend = 0.25 P for trend = 0.10
Interaction between receptor status and isoflavones P for interaction = 0.91 P for interaction = 0.31

aModels adjusted for stage, grade, ER/PR status, menopausal status, chemotherapy treatment, radiation, age, education, race, soy supplements intervention group, presence of hot flash symptoms, and their interaction; the unstratified model was also adjusted for tamoxifen use; the model subset to women not taking tamoxifen did not adjust for race because of small cell sizes.

bNew breast cancer event includes an invasive breast cancer recurrence or a new invasive primary breast cancer.