Estimating healthy volunteer effects in the PLCO
Principal Investigator
Name
Filip Pirsl
Degrees
Ph.D., Sc.M.
Institution
National Cancer Institute
Position Title
Postdoctoral Fellow
Email
About this CDAS Project
Study
PLCO
(Learn more about this study)
Project ID
PLCO-1767
Initial CDAS Request Approval
Dec 16, 2024
Title
Estimating healthy volunteer effects in the PLCO
Summary
The healthy volunteer effect is a type of selection bias in which study participants are healthier than the target population and may result in attenuated exposure-outcome estimates relative to target estimands. Healthy volunteer effects have been described in numerous randomized trials and cohort studies, including the PLCO (Pinsky et al, Am J Epidemiol 2007). Comparison of PLCO demographics, cancer incidence (except primary PLCO outcome cancers: prostate, lung, colorectal, ovarian), and survival to US population estimates demonstrated a substantially healthier PLCO study population compared to the general population. In this project, we will describe healthy volunteer effects using long-term PLCO follow-up and including primary PLCO outcome cancers. Findings obtained from PLCO data will complement and be compared to similar estimates obtained from other population studies of cancer to describe effects in trial and cohort populations.
Aims
The aim of this project is to quantify healthy volunteer effects in the PLCO by comparing cancer incidence and survival to general population estimates. Specifically, this project will estimate standardized incidence ratios (SIR) for any cancer and specific cancer types as well as all-cause, cancer-specific, and non-cancer standardized mortality ratios (SMR) among PLCO participants with no prior history of cancer compared to CDC Wonder data. SIR and SMR will also be estimated stratified by age (<60 and 60+), sex, and race-ethnicity to identify any heterogeneity in healthy volunteer effects by key demographic indicators.
Collaborators
Hormuzd Katki, Shahinaz Gadalla