Table 4.

Independent effects of breast density and BMI on breast cancer risk

Age-adjusted multivariate relative risk (95% CI)
Premenopausal women (n = 24,006)Postmenopausal women (all) (n = 36,867)Postmenopausal women not using hormones (n = 19,437)Postmenopausal women using hormones (n = 13,233)
BMI (kg/m2)
    <22.01.001.001.001.00
    22.0–24.90.71 (0.53–0.94)1.17 (0.94–1.45)1.06 (0.77–1.47)1.25 (0.91–1.73)
    25.0–27.40.77 (0.55–1.09)1.25 (0.99–1.57)1.33 (0.96–1.86)1.04 (0.72–1.51)
    27.5–29.90.79 (0.53–1.20)1.43 (1.12–1.83)1.43 (1.00–2.04)1.35 (0.91–1.99)
    ≥300.85 (0.61–1.20)1.54 (1.23–1.93)1.67 (1.22–2.31)1.30 (0.90–1.88)
Density
    Entirely fat1.001.001.001.00
    Scattered2.49 (0.91–6.68)2.26 (1.64–3.12)2.06 (1.40–3.03)2.35 (1.15–4.79)
    Heterogeneous3.64 (1.33–9.96)3.08 (2.20–4.32)2.41 (1.57–3.68)3.80 (1.80–7.62)
    Extremely4.35 (1.55–12.20)4.47 (2.96–6.74)3.55 (1.99–6.36)4.20 (1.90–9.30)