Press "Enter" to skip to content

Work at Ground Zero Linked to Long-Term CVD Risk

Firefighters who worked at the World Trade Center (WTC) site following 9/11 had a statistically significant increase in long-term risk for cardiovascular disease (CVD), researchers said.

Both early arrival at the WTC site after the towers fell and repeated exposure during 6 months or more working at the site appeared to be linked to elevated CVD risk, compared with later arrival and working less total time at the site after the researchers adjusted for multiple heart disease risk factors.

Hillel Cohen, DrPH, of Albert Einstein College of Medicine in the Bronx, New York, and colleagues followed nearly 9,800 New York City firefighters who worked at the WTC site since 9/11, with close to 500 CV events reported as of Dec. 31, 2017.

The study, published online in JAMA Network Open, showed that compared with firefighters who arrived at the WTC after the morning of 9/11, those who arrived during the morning (earliest responders) had a 44% increase in age-adjusted risk for CVD events in multivariable analysis (hazard ratio 1.44; 95% CI 1.09-1.90).

Working at the site for 6 months or more following 9/11 was associated with a 30% increased risk for long-term CVD events, compared with working at the site for a shorter time in fully-adjusted modeling (HR 1.30; 95% CI 1.05-1.60).

“The findings appear to reinforce the importance of long-term monitoring of the health of survivors of disasters,” the researchers wrote.

A total of 343 Fire Department of New York (FDNY) firefighters were killed on 9/11, and it was recently reported that an additional 200 firefighters who worked to clear the site in the aftermath of the terrorist attacks have now died of illnesses related to their exposures.

Respiratory disorders, including bronchiolar and interstitial lung diseases, have been widely reported among workers at the WTC site, along with a host of other diseases.

Studies show a strong association between prolonged exposure to air pollution and increased CV risk, but previous studies examining WTC exposure as a risk factor for long-term CVD have shown mixed results, Cohen and colleagues noted.

They used multivariable Cox regression analysis to estimate CV risk related to arrival time at the WTC site and total duration of work time over 16 years of follow-up.

The study cohort included 9,796 firefighters whose mean age on Sept. 11, 2001 was 40.3 years. A total of 7,210 (73.6%) had never smoked cigarettes.

“Both high-level acute exposure with arrival before noon on 9/11 and recurrent post-acute exposure with prolonged duration of work at the site were significantly associated with long-term risk of the primary CVD outcome and all CVD,” the researchers wrote.

Study limitations, the team said, included lack of information on exposure to specific concentrations of particulate matter less than 2.5 μm (PM2.5) and other components of dust at Ground Zero, as well as lack of access to the work records and hospital records.

Study strengths included the 16-year follow-up, and the fact that the few (less than 0.5%) participants who exhibited evidence of CVD at baseline were not included in the study.

“The CVD outcomes were based on physician-documented diagnoses in the FDNY medical record rather than patient self-report that others have used,” the researchers wrote. “These diagnoses, along with physicians’ notes, were clinically reviewed for classification as primary outcome events or all-CVD events.”

The research was funded by the National Institute for Occupational Safety and Health (NIOSH).

Cohen and co-authors received funding from NIOSH’s World Trade Center Health Program.