Table 6.

RRs of histologic subgroups of breast cancer according to usage of fertility drugs

Fertility drugNo. cases/no. in subcohort
Adjusted RR* (95% CI)
DuctalLobularOtherDuctalLobularOther
Gonadotrophins
    Never231/1,06122/1,06142/1,0611.001.001.00
    Ever29/1654/1653/1651.13 (0.71-1.81)1.96 (0.66-5.82)0.70 (0.22-2.22)
Clomiphene
    Never180/82118/82131/8211.001.001.00
    Ever80/4058/40514/4051.06 (0.79-1.43)0.91 (0.47-1.80)1.10 (0.62-1.95)
hCG
    Never187/83118/83132/8311.001.001.00
    Ever73/3958/39513/3950.92 (0.67-1.25)1.26 (0.66-2.41)1.08 (0.61-1.91)
GnRH
    Never243/1,12825/1,12845/1,1281.001.001.00
    Ever17/981/980/981.43 (0.75-2.70)1.44 (0.11-18.45)
Progesterone
    Never252/1,21326/1,21345/1,2131.001.001.00
    Ever8/130/130/134.09 (1.62-10.37)
  • NOTE: All analyses were stratified according to calendar year (in categories) and age at start of follow-up (in categories).

  • * RRs adjusted for childbirth (ever/never), and number of additional births (linear).

  • Follicle-stimulating hormone and human menopausal gonadotrophin.