Mortality in a cohort of WTC-exposed law-enforcement officers compared to non-WTC law-enforcement officers

TL;DR

Law enforcement officers involved in the WTC rescue had lower mortality rates compared to both non-WTC officers and the general population, possibly due to better healthcare access.

Contribution

The study identifies healthcare access as a potential factor for lower mortality in WTC-exposed workers beyond the healthy worker effect.

Findings

WTC-exposed law enforcement officers had significantly lower all-cause mortality rates compared to the general population.

Adjusted mortality relative risk for WTC officers compared to Buffalo officers was 0.30 (95% CI 0.23–0.40).

Cause-specific mortality rates were significantly lower in the WTC cohort compared to both the general population and Buffalo officers.

Abstract

World Trade Center (WTC) rescue/recovery workers were exposed to materials hazardous to health. Previous studies found lower than expected mortality among WTC rescue/recovery workers when compared to general populations, possibly due to healthy worker effects, better healthcare access and/or incomparability of the groups. We compared mortality rates in WTC-exposed law enforcement officers (LEOs) with rates in LEOs employed by the Buffalo, NY, Police Department. We also compared both cohorts to the general population.

Follow-up began at the later of one year after enrollment date or 1/1/2005 and ended at the earlier of death date or 12/31/2018. Analyses were restricted to ages 40–79 years (N = 11,476 WTC LEOs, N = 1668 non-WTC LEOs). We estimated standardized mortality ratios (SMRs) in each cohort using stratum-specific US mortality rates. Relative rates (RRs) and 95% CIs were estimated for the WTC vs. the Buffalo cohort using Poisson regression models adjusted for sex, race, age-group, and calendar-period.

185 deaths were observed in the WTC cohort and 186 in the Buffalo cohort. All-cause and cause-specific SMRs were significantly lower in the WTC cohort. Similarly, the adjusted all-cause mortality RR for the WTC vs. Buffalo cohorts was 0.30 (95% CI = 0.23–0.40). The cause-specific mortality RRs were all significantly < 1.

We found lower overall and cause-specific mortality rates in WTC LEOs compared with both the general population and Buffalo LEOs. These results suggest that factors other than healthy worker effects, such as access to healthcare via the WTC Health Program, contribute to lower mortality rates in WTC rescue/recovery workers.