Table 4.

Multivariate RR (95% CI) of breast cancer according to quartiles of estrogen metabolites

Quartile 1Quartile 2Quartile 3Quartile 4Ptrend
2-OH estrone, pg/mL<9898-<125125-<164≥164
    Cases/controls73/16584/17195/16888/171
    RR (95% CI)1.00 (reference)1.13 (0.75-1.69)1.30 (0.88-1.93)1.19 (0.80-1.79)0.40
ER+/PR+*
    Cases/controls40/16543/17140/16841/171
    RR (95% CI)1.00 (reference)1.07 (0.65-1.77)1.04 (0.62-1.74)1.00 (0.60-1.67)0.95
ER-/PR-*
    Cases/controls5/1657/17113/16816/171
    RR (95% CI)1.00 (reference)1.62 (0.47-5.54)3.03 (1.00-9.15)3.65 (1.23-10.81)0.01
16α-OH estrone, pg/mL<292292-<349349-<413≥413
    Cases/controls78/168102/16676/17384/170
    RR (95% CI)1.00 (reference)1.38 (0.95-2.02)1.01 (0.68-1.50)1.04 (0.71-1.53)0.81
ER+/PR+*
    Cases/controls40/16845/16637/17342/170
    RR (95% CI)1.00 (reference)1.27 (0.77-2.09)0.89 (0.53-1.50)1.05 (0.63-1.73)0.85
ER-/PR-*
    Cases/controls7/16818/1667/1739/170
    RR (95% CI)1.00 (reference)3.05 (1.16-8.03)0.88 (0.28-2.73)1.39 (0.47-4.06)0.78
2-OH:16α-OH estrone ratio<0.280.28-<0.370.37-<0.48≥0.48
    Cases/controls74/16989/16887/17090/168
    RR (95% CI)1.00 (reference)1.33 (0.89-1.99)1.24 (0.83-1.85)1.30 (0.87-1.95)0.35
ER+/PR+*
    Cases/controls41/16944/16843/17036/168
    RR (95% CI)1.00 (reference)1.16 (0.70-1.90)1.12 (0.68-1.85)0.88 (0.52-1.48)0.51
ER-/PR-*
    Cases/controls5/1695/16815/17016/168
     RR (95% CI)1.00 (reference)0.95 (0.25-3.57)2.89 (0.97-8.66)3.70 (1.24-11.09)0.004
  • NOTE: Multivariate models controlled for BMI at age 18 y (<21, 21-22.9, 23-24.9, ≥25 kg/m2), family history of breast cancer (yes, no), age at menarche (<12, 12, 13, ≥14 y), age at first birth and parity (nulliparous; 1-4 children, first birth <25 y; 1-4 children, first birth 25-29 y; 1-4 children, first birth ≥30 y; ≥5 children, first birth <25 y; ≥5 children, first birth ≥25 y), age at menopause (<46, 46-50, 51-55, ≥56 y), and duration of past PMH use (continuous); unconditional multivariate models (for ER/PR analyses) additionally controlled for matching factors [age (<55, 55-59, 60-64, ≥65 y), date of blood draw [6-mo groups], time of blood draw [1:00-8:00 a.m., 9:00 a.m.-12:00 p.m., 1:00 p.m.-12:00 a.m.], and fasting status (<10 versus ≥10 h)].

  • * Pheterogeneity values between ER+/PR+ and ER-/PR- were 0.02 for 2-OH estrone, 0.81 for 16α-OH estrone, and 0.005 for 2:16α OH estrone ratio.