Table 3.

Raw incidence and relative risk of breast cancer by breast density category

DensityNo. of womenNo. of person-yearsNo. of cancer casesRaw incidence per 100,000 person-yearsAge-adjusted relative risk (95% CI)
All women
    Entirely fat4,40914,278453151.00
    Scattered33,397105,2226356032.19 (1.62–2.97)
    Heterogeneous19,01556,9534866782.97 (2.17–4.06)
    Extremely5,02315,8891257874.02 (2.84–5.68)
Premenopausal
    Entirely fat7842,50241601.00
    Scattered10,54431,7991203772.47 (0.92–6.69)
    Heterogeneous9,65127,7181485343.70 (1.37–9.98)
    Extremely3,25910,120656424.61 (1.68–12.64)
Postmenopausal
    Entirely fat3,62511,776413481.00
    Scattered22,85373,4235157012.18 (1.58–2.99)
    Heterogeneous9,36429,2352388142.79 (2.00–3.88)
    Extremely1,7645,769601,0403.88 (2.60–5.78)