Table 4.

RRs of breast cancer according to usage of fertility drugs

Fertility drugNo. cases/no. in subcohort
Adjusted RR* (95% CI)
GonadotrophinsClomiphenehCGGnRHProgesteroneGonadotrophinsClomiphenehCGGnRHProgesterone
Use of fertility drugs
    Never295/1,061229/82237/831313/1,128323/1,2131.001.001.001.001.00
    Ever36/165102/40594/39518/988/131.20 (0.82-1.78)1.08 (0.85-1.39)0.94 (0.73-1.21)1.28 (0.75-2.19)3.36 (1.60-7.07)
No. cycles
    1-425/12264/21653/22716/918/131.15 (0.73-1.81)1.26 (0.95-1.69)0.89 (0.66-1.22)1.20 (0.68-2.13)3.36 (1.60-7.07)
    5-911/3826/11830/1122/70/01.67 (0.89-3.12)0.89 (0.58-1.34)1.10 (0.74-1.62)2.32 (0.55-9.79)
    ≥100/512/7111/560/00/00.83 (0.46-1.50)0.81 (0.44-1.49)
Year since first use
    ≤421/4825/3119/4214/472/31.22 (0.70-2.12)1.14 (0.69-1.87)0.72 (0.42-1.24)1.22 (0.61-2.44)1.75 (0.31-9.93)
    5-913/8031/9325/914/454/61.96 (1.06-3.64)1.31 (0.86-2.00)1.11 (0.69-1.78)1.55 (0.56-4.31)6.28 (1.87-21.09)
    10-141/1817/10216/700/61/30.42 (0.06-3.03)0.75 (0.43-1.28)0.76 (0.44-1.31)3.48 (0.52-23.56)
    ≥151/1929/17934/1920/01/10.35 (0.04-2.72)1.14 (0.73-1.80)1.11 (0.72-1.72)2.84 (0.19-42-44)
  • 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.