Table 4.

RR of breast cancer and 95% CI by tertiles of soy intake during childhood, adolescence, and adulthood among Asian American women born in the East and in the West

Soy intake*Born in the East
Born in the West
Cases/controlsRR (95% CI)Cases/controlsRR (95% CI)
Childhood
    Low17/151.024/351.0
    Medium6/140.21 (0.04-1.12)24/370.50 (0.20-1.30)
    High11/160.46 (0.08-2.68)15/360.32 (0.12-0.86)
    Ptrend0.410.03
    Pinteraction0.41
Adolescence
    Low133/1971.082/1181.0
    Medium72/1340.88 (0.59-1.32)114/1681.13 (0.73-1.75)
    High109/2210.80 (0.52-1.22)66/1020.94 (0.57-1.54)
    Ptrend0.330.60
    Pinteraction0.90
Adulthood
    Low126/1741.079/1221.0
    Medium105/1860.77 (0.53-1.12)117/1531.22 (0.82-1.82)
    High90/2000.66 (0.42-1.01)74/1250.87 (0.55-1.37)
    Ptrend0.070.37
    Pinteraction0.33
  • NOTE: The fully adjusted model is presented. RR are adjusted for study design variables [age at diagnosis (20-39, 40-44, 45-49, ≥50 y), ethnicity (Chinese, Japanese, Filipino), and study center (Hawaii, Los Angeles, San Francisco-Oakland)] and parity/age at first live birth (nulliparous/never pregnant, 1-2 live births/age at first birth ≤20 y, ≥3 live births/age at first live birth ≤20 y, 1-2 live births/age at first live birth ≥21 y, ≥3 live births/age at first live birth ≥21 y, missing), menopausal status at diagnosis (premenopausal, postmenopausal, missing/other), age at menarche (<13 y, ≥13 y, missing/other), family history of breast cancer (yes, no), and personal history of benign breast disease (yes, no, missing).

  • * Soy intake was stratified as tertiles based on the frequency distribution of intake in each period among all controls, both those born in the East and West. The low tertile were used as the reference category.

  • P values for trend were calculated by assigning to each tertile the median soy intake for all subjects in the tertile.