Delayed effect of aspirin use and colorectal cancer (CRC) risk: timeline of analyses according to duration of use in the Nurses’ Health Study (NHS) and Health Professionals Follow-up Study (HPFS). While examining the delayed effects of duration of aspirin use in CRC chemoprevention: In the NHS, the first “remote period” was 1980-1982, and the first “subsequent 10-year period” was 1982-1992. The second “remote period” was 1980-1984, and the second “subsequent 10-year period” was 1984-1994. The last remote period was 1980-2002, then the last subsequent 10-year period was 2002-2012. Similarly, in the HPFS, the first remote period was 1986-1988, and the first subsequent 10-year period was 1988-1998. The last remote period was 1986-2002, and the last subsequent 10-year period was 2002-2012. The follow-up period was from the end of the first subsequent 10-year period (ie, 1992 in the NHS; 1998 in HPFS) to 2014.