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. Author manuscript; available in PMC: 2021 Apr 1.
Published in final edited form as: Cancer Epidemiol Biomarkers Prev. 2020 Jul 29;29(10):2048–2056. doi: 10.1158/1055-9965.EPI-20-0358

Table 1.

Characteristics of the 1,071,653 women with 21,253 breast cancers in the study cohort by race/ethnicity and menopausal status.a

White Black Asian Hispanic
N (%) N (%) N (%) N (%)
Premenopausal
 Breast Cancer Status
  No Breast Cancer 371,515 (98.6) 33,712 (99.1) 50,835 (98.9) 55,902 (99.1)
  Breast Cancer 5,462 (1.4) 314 (0.9) 576 (1.1) 535 (0.9)
 Age Group, Years
  35–39 40,833 (10.8) 3,336 (9.8) 3,599 (7.0) 6,959 (12.3)
  40–44 148,762 (39.5) 13,114 (38.5) 20,284 (39.5) 26,699 (47.3)
  45–49 110,847 (29.4) 10,011 (29.4) 17,222 (33.5) 14,743 (26.1)
  50–54 76,536 (20.3) 7,565 (22.2) 10,306 (20.0) 8,036 (14.2)
 Body Mass Index (kg/m2)
  Underweight (<18.5) 6,437 (1.7) 208 (0.6) 2,044 (4.0) 527 (0.9)
  Normal (18.5–24.9) 183,137 (48.6) 5,642 (16.6) 34,326 (66.8) 20,351 (36.1)
  Overweight (25.0–29.9) 97,807 (25.9) 9,680 (28.4) 11,307 (22.0) 18,606 (33.0)
  Obese I (30.0–34.9) 49,443 (13.1) 8,368 (24.6) 2,776 (5.4) 10,372 (18.4)
  Obese II/III (≥35.0) 40,154 (10.7) 10,128 (29.8) 958 (1.9) 6,582 (11.7)
 BI-RADS Breast Density
  Almost Entirely Fat 19,185 (5.1) 2,220 (6.5) 782 (1.5) 3,886 (6.9)
  Scattered Fibroglandular 126,541 (33.6) 12,749 (37.5) 8,866 (17.2) 20,634 (36.6)
  Heterogeneously Dense 176,850 (46.9) 15,711 (46.2) 27,616 (53.7) 25,648 (45.4)
  Extremely Dense 54,402 (14.4) 3,346 (9.8) 14,148 (27.5) 6,268 (11.1)
 Observations per Woman
  1 150,927 (40.0) 14,260 (41.9) 23,196 (45.1) 29,964 (53.1)
  2 79,456 (21.1) 7,519 (22.1) 11,713 (22.8) 12,370 (21.9)
  3 48,726 (12.9) 4,563 (13.4) 6,712 (13.1) 6,285 (11.1)
  4 31,161 (8.3) 2,829 (8.3) 3,862 (7.5) 3,333 (5.9)
  5 or more 66,708 (17.7) 4,856 (14.3) 5,930 (11.5) 4,485 (7.9)
Postmenopausal
 Total Women
  No Breast Cancer 492,441 (97.6) 48,479 (98.5) 65,048 (98.7) 59,640 (98.5)
  Breast Cancer 11,854 (2.4) 756 (1.5) 866 (1.3) 881 (1.5)
 Age Group, Years
  5–44 6,432 (1.3) 402 (0.8) 362 (0.5) 1,029 (1.7)
  45–54 79,894 (15.8) 6,020 (12.2) 9,881 (15.0) 8,663 (14.3)
  55–64 231,259 (45.9) 23,747 (48.2) 35,474 (53.8) 30,435 (50.3)
  65–74 126,740 (25.1) 13,766 (28.0) 15,159 (23.0) 14,846 (24.5)
  75–84 59,971 (11.9) 5,300 (10.8) 5,039 (7.6) 5,548 (9.2)
 Body Mass Index (kg/m2)
  Underweight (<18.5) 8,612 (1.7) 404 (0.8) 2,589 (3.9) 634 (1.0)
  Normal (18.5–24.9) 201,912 (40.0) 8,125 (16.5) 40,343 (61.2) 18,966 (31.3)
  Overweight (25.0–29.9) 154,865 (30.7) 15,194 (30.9) 17,732 (26.9) 22,181 (36.6)
  Obese I (30.0–34.9) 81,520 (16.2) 12,757 (25.9) 3,929 (6.0) 12,123 (20.0)
  Obese II/III (≥35.0) 57,386 (11.4) 12,755 (25.9) 1,321 (2.0) 6,618 (10.9)
 BI-RADS Breast Density
  Almost Entirely Fat 65,350 (13.0) 6,417 (13.0) 4,628 (7.0) 10,418 (17.2)
  Scattered Fibroglandular 246,077 (48.8) 26,992 (54.8) 25,202 (38.2) 31,400 (51.9)
  Heterogeneously Dense 167,016 (33.1) 14,349 (29.1) 29,448 (44.7) 16,471 (27.2)
  Extremely Dense 25,852 (5.1) 1,478 (3.0) 6,637 (10.1) 2,232 (3.7)
 Observations per Woman
  1 151,927 (30.1) 14,988 (30.4) 24,382 (37.0) 23,798 (39.3)
  2 97,612 (19.4) 10,160 (20.6) 15,371 (23.3) 13,348 (22.1)
  3 65,227 (12.9) 7,035 (14.3) 8,948 (13.6) 8,178 (13.5)
  4 45,859 (9.1) 4,553 (9.2) 5,668 (8.6) 5,588 (9.2)
  5 or more 143,670 (28.5) 12,499 (25.4) 11,547 (17.5) 9,609 (15.9)
a

Frequencies differ from the text due to inverse weighting by the number of observations per woman, rounding, and transitioning of 127,165 women from pre- to postmenopausal status during the study who contributed observations to both cohorts.

Abbreviations: kg, kilograms; m, meters; BI-RADS, Breast Imaging Reporting and Data System.