Table 1 Summary characteristics of the lifepool participants by age groups
Characteristic | Age at reference screen (years) | ||
|---|---|---|---|
50–69 | 50–59 | 60–69 | |
Number of subjects (N) | 40,158 | 20,216 | 19,942 |
Dates | |||
 Reference screen (range) | 1 Jul 2010 to 6 Oct 2014 | 1 Jul 2010 to 6 Oct 2014 | 1 Jul 2010 to 6 Oct 2014 |
 Questionnaire completion (range) | 1 Jul 2010 to 1 Oct 2014 | 1 Jul 2010 to 23 Sep 2014 | 31 Jul 2010 to 1 Oct 2014 |
Observation time, years (median, range) | 4.3 (0.3–6.5) | 4.3 (0.3–6.5) | 4.3 (0.3–6.5) |
Age | |||
 Reference screen, years (median, range) | 59 (50–69) | 55 (50–59) | 64 (60–69) |
 Diagnosis, years (median, range) | 63 (51–73) | 58 (51–64) | 67 (61–73) |
 Reference screening round (median, range) | 5 (1–18) | 4 (1–18) | 7 (1–18) |
Diagnoses (invasive breast cancer) | |||
 Number (%) | 564 (1.4%) | 244 (1.2%) | 320 (1.6%) |
Follow-up period | |||
 Time from reference screen to diagnosis, days (median, range) | 813 (28–1938) | 818 (28–1714) | 807 (73–1938) |
 Women screened during the follow-up period (n, %) | 38,060 (95%) | 19,141 (95%) | 18,919 (95%) |
 Of women screened during the follow-up period, number of screens per 2 years of follow-up (median, range) | 0.8 (0.3–2.0) | 0.8 (0.3–2.0) | 0.8 (0.3–1.9) |