Firefighters who arrived first at World Trade Center immediately after 9/11 attack have 44% higher risk of heart disease
Exposure to dust immediately after the collapse of the World Trade Center (WTC) on September 11, 2011, has now been associated with a significantly increased long-term risk of heart disease. An analysis reveals that New York firefighters, who arrived first at the WTC site, when the airborne dust was thickest, have a 44% increased risk of heart diseases as compared to those who came later in the day.
The study included 9,796 male firefighters - with an average age of 40 on September 11, 2001 - of which most (7,210) were never smokers. “The increase in risk was significant, even taking into account known cardiovascular disease risk factors such as age, hypertension, elevated cholesterol, diabetes, and smoking,” says study leader Dr. David J. Prezant, a professor of medicine at Einstein, a pulmonary disease specialist at Montefiore, and chief medical officer of the Fire Department of the City of New York (FDNY).
The findings, say the research team, underscores the importance of monitoring the long-term health of anyone exposed to massive environmental disasters - such as 9/11 attacks - even many years after the event. The study, published in JAMA Network Open, was conducted by researchers at Albert Einstein College of Medicine, Montefiore Health System, and FDNY.
The collapse of the World Trade Center towers on September 11, 2001, produced an enormous dust cloud and created a hazardous environment for first responders, workers, and area residents. Thousands of FDNY firefighters were exposed on 9/11 and for up to 10 months after the incident.
Traditional heart disease risk factors include hypertension, high cholesterol, diabetes, smoking, older age, and body mass index (BMI). Environmental exposures to the small, airborne particulate matter have increasingly been recognized as also contributing to heart disease risk, including by a 2004 American Heart Association scientific statement. A 2010 update concluded that the body of evidence was “consistent with a causal relationship between PM2.5 exposure and cardiovascular morbidity (rate of disease in a population) and mortality (death).”
Previous studies have reported that exposure to WTC is linked with immediate and long-term risk of adverse health effects such as post-traumatic stress disorder (PTSD), respiratory problems, and several types of cancer. While some studies have tried to examine the link between WTC exposure and heart disease, the results were not consistent as they were based on self-reported health measures primarily.
For the current research, the firefighters were divided into four groups: those who first arrived at the WTC site during the morning of 9/11 (who were believed to receive the highest dust exposure), those who first arrived that afternoon, those who first came on September 12, and those who first arrived between days 3 and 14.
The research team used two measures of exposure to the WTC disaster - arrival time and work duration at the site to examine the primary outcome of long-term risk of cardiovascular disease, which includes heart attack, stroke, unstable angina, coronary artery surgery or angioplasty, or death from cardiovascular disease. Both acute exposure (arriving at the site on the morning of the 9/11 attacks) and repeated exposure during six or more months of work at the site, according to the researchers, appear to be associated with higher risk of cardiovascular disease compared with those firefighters who arrived later and worked for less time at the site.
“High-level acute exposure with arrival before noon on 9/11 and recurrent post-acute exposure with prolonged duration of work at the site was significantly associated with long-term risk of the primary cardiovascular disease (CVD) outcome and all CVD. This finding suggests that discrete exposure to dust and products of combustion could have initiated persistent pathologic processes related, in part, to chronic inflammation that increased CVD risk years later,” state the findings published in JAMA Network Open.
The researchers reviewed 16 years of medical records, physician examinations, and questionnaires to assess the participants for primary and secondary heart disease events. According to experts, primary cardiovascular disease events were defined as myocardial infarction, stroke, unstable angina, coronary artery surgery or angioplasty, or CVD death.
“Secondary events included transient ischemic attack, angina defined as either angina medication or cardiac catheterization without intervention, cardiomyopathy, and “other CVD”: aortic aneurysm, peripheral arterial vascular intervention, and carotid artery surgery,” says the study.
In more than 16 years of follow-up, there were 489 primary outcome events, and the highest was among the group that arrived first. Further, there were six cardiovascular disease deaths in all. As compared to the first group that came during and immediately after the collapse, and had a 44% higher risk of experiencing both primary and secondary cardiovascular disease events, those who worked at the WTC site for six months or more were 30% more likely to have experienced a primary or secondary event.
According to co-lead author Rachel Zeig-Owens, a research assistant professor of epidemiology & population health at Einstein and an epidemiologist at Montefiore and FDNY, the results reinforce the importance of long-term monitoring of the health of survivors of disasters. “By screening for and treating the other CVD risk factors such as elevated cholesterol, hypertension, obesity, and smoking, we are able to lower the overall risk of CVD in those most exposed to the World Trade Center disaster,” she says.