Table 4.

Breast cancer risk and radiation exposure: baseline depends on city, in-city status, age ATB, attained age, and reproductive status ATB

Dose category (Gy)Overall: all reproductive status categories combined
SubjectsPerson-yearsCasesRR (95% CI)*
<0.00514,830443,9662611 (Reference)
0.005-0.4913,075397,3452661.21 (0.99-1.48)
0.50-0.991,24336,102542.62 (1.93-3.57)
1.00-1.9967018,968403.64 (2.57-5.16)
≥2.0029576,934204.83 (3.03-7.70)
ERR per Gy (e = 30, a = 70)1.44 (0.79-2.29)
Age at exposure (% Δ/10-y increase)−0.05 (−33 to 34%)
Attained age (power)−0.81 (−2.5 to 0.87)
EAR per Gy (e = 30, a = 70)12.13 (7.65-17.20)
Age at exposure (% Δ/10-y increase)−0.44 (−57% to 26%)
Attained age (power)2.8 (1.7-3.9)
  • *95% CI calculated from the profile likelihood for hazard ratios and ERR and EAR per Gy terms and from Wald's method for age at exposure and attained age terms.