In 1992, about 184,000 participants from CPS-II enrolled in the CPS-II Nutrition cohort, allowing us to collect detailed information on diet and other risk factors for cancer. In 1997, we started sending sex-specific surveys every 2 years. While CPS-II participants are only being followed for cancer mortality, we're following nutrition participants for cancer incidence as well as cancer mortality until 2022.
The majority of participants answered the long survey every 2 years. We developed shorter surveys for the participants who struggled to complete it, and we also offered to conduct brief surveys over the phone.