Table 1 Mean age at third examination or diagnosis, time of follow-up and distribution of breast cancer risk factors for women with or without screen-detected or interval cancer among participants of BreastScreen Norway, 2007–2020
From: Mammographic density by time and breast: a retrospective cohort study from BreastScreen Norway
Variable | Women with screen-detected breast cancer | Women with interval breast cancer | Women with screen-detected and interval breast cancer | Women without breast cancer | Total |
|---|---|---|---|---|---|
Study sample 1 | n = 970 | n = 308 | n = 1278 | n = 76,904 | n = 78,182 |
Age (years, mean, SD, range) | 62.2 (4.4, 53–71) | 61.8 (4.8, 53–70) | 62.1 (4.5, 53–71) | 62.3 (5.0, 52–71) | 62.3 (5.0, 52–71) |
Time of follow-up (days, mean, SD) | 1503.4 (53.5) | 1943.8 (180.0) | 1609.5 (213.3) | 2217.4 (59.4) | 2207.4 (100.8) |
History of benign breast disease (n, %) | 32 (3.3%) | 8 (2.6%) | 40 (3.1%) | 1759 (2.3%) | 1799 (2.3%) |
Volpara Density Grade 5th edition | Â | Â | Â | Â | Â |
1 (n, %) | 120 (12.4%) | 14 (4.5%) | 134 (10.5%) | 15,831 (20.6%) | 15,965 (20.4%) |
2 (n, %) | 534 (55.1%) | 136 (44.2%) | 670 (52.4%) | 39,937 (51.9%) | 40,607 (51.9%) |
3 (n, %) | 273 (28.1%) | 128 (41.6%) | 401 (31.4%) | 17,602 (22.9%) | 18,003 (23.0%) |
4 (n, %) | 43 (4.4%) | 30 (9.7%) | 73 (5.7%) | 3534 (4.6%) | 3607 (4.6%) |
Study sample 2 | n = 541 | n = 173 | n = 714 | n = 42,180 | 42,894 |
Age (years, mean, SD, range) | 62.1 (4.3, 53–71) | 61.3 (4.7, 53–70) | 61.9 (4.4, 53–71) | 62.4 (4.7, 52–71) | 62.4 (4.7, 52–71) |
Time of follow-up (days, mean, SD) | 1500.6 (49.2) | 1922.8 (192.2) | 1602.9 (208.6) | 2216.8 (58.1) | 2206.6 (101.1) |
History of benign breast disease (n, %) | 16 (3.0%) | 5 (2.9%) | 21 (2.9%) | 979 (2.3%) | 1000 (2.3%) |
Volpara Density Grade 5th edition | Â | Â | Â | Â | Â |
1 (n, %) | 60 (11.1%) | 7 (4.2%) | 67 (9.4%) | 8661 (20.5%) | 8728 (20.3%) |
2 (n, %) | 301 (55.6%) | 70 (40.5%) | 371 (52.0%) | 21,920 (52.0%) | 22,291 (52.0%) |
3 (n, %) | 156 (28.8%) | 78 (45.1%) | 234 (32.8%) | 9726 (23.1%) | 9960 (23.2%) |
4 (n, %) | 24 (4.4%) | 18 (10.4%) | 42 (5.9%) | 1873 (4.4%) | 1915 (4.5%) |
Body mass index (kg/m2, mean, SD) | 26.4 (5.2) | 25.5 (4.2) | 26.2 (5.0) | 25.7 (4.3) | 25.7 (4.4) |
First- or second-degree family history of breast cancer, yes, n, %) | 60 (11.1%) | 24 (13.9%) | 84 (11.8%) | 4116 (9.8%) | 4200 (9.8%) |
Ever used hormone therapy in screening period (n, %) | 244 (45.1%) | 83 (48.0%) | 327 (45.8%) | 15,477 (36.7%) | 15,804 (36.8%) |
Ever used alcohol (n, %) | 418 (77.3%) | 136 (78.6%) | 554 (77.6%) | 33,248 (78.8%) | 33,802 (78.8%) |
Ever smoked (n, %) | 304 (56.2%) | 91 (52.6%) | 395 (55.3%) | 23,443 (55.6%) | 23,838 (55.6%) |