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

## TL;DR

This study found that racial and ethnic disparities in cancer-related mortality exist among 9/11 disaster survivors, with socioeconomic factors playing a key role.

## Contribution

The study is the first to examine racial and ethnic disparities in mortality among disaster-exposed cancer patients, highlighting the role of socioeconomic status.

## Key findings

- Non-Hispanic Black enrollees had higher all-cause and non-cancer mortality risks compared to non-Hispanic Whites.
- Hispanic enrollees had higher cancer mortality risks, but these were mediated by socioeconomic status.
- Socioeconomic status explained 24% and 29% of the mortality disparities for non-Hispanic Blacks and Hispanics, respectively.

## Abstract

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.

This study among 9/11‐exposed individuals with post‐9/11 cancer found that, compared with non‐Hispanic White enrollees, non‐Hispanic Black enrollees had statistically significantly higher risk for non‐cancer mortality, and Hispanic enrollees had higher risk for cancer‐related mortality. The mortality disparity between Hispanic and non‐Hispanic White enrollees was mediated by socioeconomic status.