Figure 1
Participant Flow in the BCDDP Follow-Up Study: (A) Inclusion criteria for the analytic cohort and (B) Timeline of follow-up for participants in the analytic cohort. 1From the original screening population, the BCDDP follow-up cohort included all 4,275 women diagnosed with breast cancer, all 25,114 women with biopsies indicating benign breast disease, all 9,628 women who were recommended for breast biopsy or surgery but did not undergo either procedure, and 25,165 participants (who neither underwent nor were recommended for breast biopsy) matched to women with breast cancer or positive biopsies for breast cancer on age, time of entry into the screening program, length of cohort participation, ethnicity, and location. 2 We excluded 5,691 subjects with a cancer (other than non-melanoma skin cancer) diagnosed prior to the 1987 questionnaire, 10 women who were lost to follow-up, 4,218 women with a missing or extreme body mass index (greater than 3 standard deviations above or below the mean), and 8,242 women with inadequate physical activity information.