Table 2

Distribution of breast cancer cases and controls and relative risksa according to parenchymal pattern by percentage of the breast showing densitiesb

Percent density (%)Parenchymal patternTotal
N1P1P2DY
Cases/ControlsRR95% CICases/ControlsRR95% CICases/ControlsRR95% CICases/ControlsRR95% CICases/ControlsRR95% CI
067/1911.0c67/1911.0d
1–2429/761.20.7–2.1240/5511.41.0–2.04/220.80.3–2.5273/6491.41.0–1.9
25–4975/1851.51.0–2.2217/3782.51.7–3.533/971.81.1–3.0325/6602.11.5–2.9
50–74187/3782.71.8–3.865/1912.51.6–3.9252/5692.61.8–3.7
≥7574/1214.12.7–6.465/1484.42.8–6.9139/2694.22.8–6.3
Total96/2671.0e315/7361.31.0–1.8478/8772.51.9–3.3167/4582.41.7–3.31056/2338
  • a All RRs are adjusted for age and body weight (see “Materials and Methods”). RRs were estimated from three separate models: one for RRs in the right margin, one for RRs in the bottom margin, and one for RRs in the body of the table.

  • b The cells including less than or equal to one case or control were removed.

  • c Reference group for RRs in the body of the table (excluding the right and bottom margins).

  • d Reference group for RRs in the right margin.

  • e Reference group for RRs in the bottom margin.