Table 2.

BMI and incidence of invasive breast cancer among postmenopausal women

STAR postmenopausalP-1 postmenopausalSTAR/P-1 postmenopausala
Form of Cox regression modelBMINNo. of eventsHR (95% CI)NNo. of eventsHR (95% CI)NNo. of eventsHR (95% CI)
Univariable assessment<25.05,8701591.002,204421.007,8831941.00
25.0–29.96,7031911.06 (0.86–1.30)2,188481.21 (0.80–1.84)8,6412281.08 (0.89–1.30)
≥30.06,9152071.14 (0.93–1.40)1,987371.07 (0.69–1.66)8,6332311.11 (0.92–1.34)
Ptrend0.220.740.29
Full multivariable assessmentb<25.05,8291591.002,194421.007,8331941.00
25.0–29.96,6581901.03 (0.83–1.27)2,182481.23 (0.81–1.86)8,5912271.06 (0.87–1.28)
≥30.06,8702061.13 (0.92–1.40)1,978361.07 (0.68–1.67)8,5812291.12 (0.92–1.36)
Ptrend0.240.730.25
Final multivariable assessmentc<25.05,8701591.002,204421.007,8831941.00
25.0–29.96,7031911.04 (0.85–1.29)2,188481.22 (0.81–1.85)8,6412281.07 (0.88–1.30)
≥30.06,9152071.16 (0.94–1.42)1,987371.09 (0.70–1.69)8,6332311.14 (0.94–1.38)
Ptrend0.160.680.17
  • aFor participants in both P-1 and STAR, only their P-1 data were included.

  • bAdjusted for treatment, Gail score, age, history of diabetes, history of oral contraceptive use, history of estrogen use, and years of cigarette smoking; STAR/P-1 combined also adjusted for trial. Those with unknown smoking status were excluded from analyses.

  • cAdjusted for treatment, Gail score, and age in STAR and STAR/P-1 combined; and treatment and Gail score in P-1.