Table 1 Mean percentage of breast density by descriptive characteristics (n = 396)

Race^*

   African-American

   Whites

Menopausal status/ HRT use^**,†

   Premenopausal

   Postmenopausal

Never used or past user of HRT

Current user of ERT

Current user of EPRT

Age at mammogram (years)

   ≤ 40

   41–45

   46–50

   51–55

   56–60

   >60

Body mass index (kg/m²)^**

   <22

   22–24.9

   25–29.9

   ≥ 30

Parity^**

   0

   1–2

   3+

Age at first birth (years)^**

   <25

   25–30

   ≥ 30

Age at menarche (years)^**

   <12

   12

   13

   >13

First-degree family history of breast cancer^**,‡

   No

   Yes