Citation
Sheridan, Paige; Chen, Chen; Thompson, Caroline A.; & Benmarhnia, Tarik (2023). Immortal Time Bias with Time-Varying Exposures in Environmental Epidemiology: A Case Study in Lung Cancer Survival. American Journal of Epidemiology, 192(10), 1754-1762. PMCID: PMC10558188Abstract
Immortal time bias is a well-recognized bias in clinical epidemiology but is rarely discussed in environmental epidemiology. Under the target trial framework, this bias is formally conceptualized as a misalignment between start of study follow-up (time zero) and treatment assignment. This misalignment can occur when attained duration of follow-up is encoded into treatment assignment using minimums, maximums, or averages. The bias can be exacerbated in the presence of time trends commonly found in environmental exposures. Using lung cancer cases from the California Cancer Registry (2000-2010) linked with PM2.5 estimates, we replicated previous studies that average PM2.5 exposure over follow-up in a time-to-event model. We compared this approach to one that ensures alignment between time zero and treatment assignment, a discrete-time approach. In the former approach, the estimated overall hazard ratio for a 5URL
http://dx.doi.org/10.1093/aje/kwad135Reference Type
Journal ArticleYear Published
2023Journal Title
American Journal of EpidemiologyAuthor(s)
Sheridan, PaigeChen, Chen
Thompson, Caroline A.
Benmarhnia, Tarik