Table 4.

HRs and 95% CIs of breast cancer for a doubling of hormone concentration by attained age during follow-up

HR (95% CI)*PtrendP
Total estradiol
    <65 y1.14 (0.55-2.37)0.720.59
    65-69 y1.40 (0.64-3.04)0.40
    >69 y1.93 (0.93-4.01)0.08
Free estradiol
    <65 y1.27 (0.73-2.21)0.400.48
    65-69 y2.00 (1.10-3.66)0.02
    >69 y1.75 (0.98-3.15)0.06
Estrone sulfate
    <65 y1.34 (0.84-2.14)0.220.20
    65-69 y1.16 (0.68-1.96)0.58
    >69 y2.10 (1.28-3.44)<0.01
Testosterone
    <65 y0.92 (0.66-1.29)0.650.01
    65-69 y0.83 (0.55-1.25)0.37
    >69 y1.70 (1.16-2.48)<0.01
DHEAS
    <65 y1.05 (0.76-1.45)0.75<0.01
    65-69 y0.79 (0.55-1.13)0.20
    >69 y1.74 (1.26-2.42)<0.01
Androstenedione
    <65 y1.03 (0.74-1.45)0.850.02
    65-69 y0.92 (0.61-1.39)0.70
    >69 y1.91 (1.26-2.88)<0.01
SHBG
    <65 y0.59 (0.35-0.98)0.040.07
    65-69 y0.25 (0.13-0.46)<0.01
    >69 y0.43 (0.24-0.76)<0.01

NOTE: HRs from the Cox model were obtained by splitting the data into the specified age bands and fitting an interaction of hormones with age band. All estimates were adjusted for country of birth, age at menarche, parity and age at first pregnancy, duration of lactation, oral contraceptive use, HRT use, alcohol consumption, energy from diet, smoking, BMI, level of education, and physical activity.

  • *Estimates from the model including the pseudocontinuous variable log2 transformed.

  • Test for linear trend using the pseudocontinuous variable log2 transformed.

  • Test for heterogeneity in HRs for hormone concentration (pseudocontinuous log2 transformed) in the three age groups.