Table 1.

Participation in National Cancer Institute DES follow-up study

DES exposedUnexposed
No. identified for the original cohorts5,0672,372
Ineligible for National Cancer Institute study
    Missing date of birth2115
    Never located56154
    Deceased before 19781115
    Lost or refused before 1978154106
    Cancer before start of follow-up89
Total eligible for National Cancer Institute study4,8172,073
    Died during follow-up5918
    Responded to 1994 questionnaire3,932 (82%)1,735 (84%)
    Responded to 1997 questionnaire3,946 (82%)1,722 (83%)
    Responded to 2001 questionnaire*3,812 (80%)1,637 (80%)
  • * Proportion of eligible subjects still alive in 2001.