Table 4.

Risk of breast cancer according to quintile of BMI (based on the distribution of BMI in controls)

Quintile of BMI
≤21.79(21.79-23.30)(23.30-25.02)(25.02-27.64)>27.64No.P*
All subjects
    Cases2452182082122311,114
    Controls2322172202242211,114
    OR (95% CI), not adjusted for density10.93 (0.7-1.2)0.89 (0.7-1.2)0.91 (0.7-1.2)1.04 (0.8-1.4)0.86
    OR (95% CI), adjusted for density11.07 (0.8-1.4)1.12 (0.8-1.5)1.21 (0.9-1.6)1.60 (1.2-2.2)0.002
Premenopausal
    Cases8654494251282
    Controls6459464652267
    OR (95% CI), not adjusted for density10.69 (0.4-1.1)0.79 (0.5-1.3)0.68 (0.4-1.2)0.76 (0.5-1.3)0.37
    OR (95% CI), adjusted for density10.88 (0.5-1.5)1.13 (0.6-2.0)1.06 (0.6-1.9)1.47 (0.8-2.7)0.18
Postmenopausal
    Cases159164159170180832
    Controls168158174178169847
    OR (95% CI), not adjusted for density11.05 (0.8-1.4)0.95 (0.7-1.3)1.02 (0.8-1.4)1.17 (0.9-1.6)0.43
    OR (95% CI), adjusted for density11.16 (0.8-1.6)1.13 (0.8-1.6)1.28 (0.9-1.8)1.67 (1.2-2.3)0.004
  • NOTE: Unmatched logistic regression, adjusted for age, age at menarche, age at first birth, parity, number of live births, menopausal status, age at menopause, hormone replacement therapy (ever/never), breast cancer in first-degree relatives (0, 1, 2+), study (NBSS, OBSP, and SMPBC), and observation time (≤2, 2-4, and >4 years), not adjusted for percentage of mammographic density. Menopausal status was omitted from the analysis for the separate menopausal groups, and age at menopause from the analysis of the premenopausal group.

  • * P value for testing the linear trend.

  • Adjusted only above factors.

  • Adjusted with above factors and percent mammographic density.