Racial and ethnic disparities in mortality among World Trade Center Health Registry enrollees with post-9/11 cancer

There are well-documented racial and ethnic disparities in mortality after cancer in the general population, but less is known about whether disparities also exist in disaster-exposed populations.

We conducted a longitudinal cohort study of 4341 enrollees in the World Trade Center Health Registry (WTCHR) with a first-ever primary invasive cancer diagnosis after 9/11/2001 and followed through 2020. We examined associations of race and ethnicity with all-cause mortality risk and cause-specific mortality risk using multivariable Cox proportional hazards regression models and Fine and Gray's proportional sub-distribution hazards models, respectively. Models were adjusted for baseline characteristics and tumor characteristics. We also examined models further adjusted for socioeconomic status (SES), and we used inverse odds weighting to formally test for mediation by SES.

Compared to non-Hispanic White enrollees with cancer, non-Hispanic Blacks had higher risks for all-cause mortality (adjusted hazard ratio (aHR) = 1.20, 95% CI = 1.02-1.41) and non-cancer mortality (aHR = 1.48, 95% CI = 1.09-2.01) in the full model. In the model without SES, Hispanic enrollees with cancer had higher risks for all-cause mortality (aHR = 1.32, 95% CI = 1.09-1.60) and cancer mortality (aHR = 1.31, 95% CI = 1.05-1.64) compared to non-Hispanic Whites; these associations became not statistically significant in the full model. In the inverse odds weighting analysis, SES explained 24% and 29% of the disparity in all-cause mortality risk observed in non-Hispanic Blacks and Hispanics, respectively, compared to non-Hispanic Whites.

This study found that there are racial and ethnic disparities in mortality after cancer in the WTCHR. Additional studies are needed to further explore the factors mediating these disparities.