Thanks to a recent study involving 9,796 fire department first responders working at the World Trade Center site after the Sept. 11, 2001 terrorist attacks, cardiovascular disease can now be added to a list of 9/11 illnesses associated with toxic dust exposure.

According to Yahoo News, the study’s results were also available online on the same day on the Journal of American Medical Association (JAMA) open network. The research was undertaken by medical professionals from Albert Einstein College of Medicine, Montefiore Health System, and the Fire Department of the City of New York (FDNY).

To date, the terrorist attack on the World Trade Center twin towers has been linked to high risk of developing numerous 9/11 illnesses over the long haul. Most notably, these diseases have included a wide variety of cancers, respiratory ailments, and post-traumatic stress disorder (PTSD). Previous attempts to link cardiovascular disease with the NYC terrorist attack have been difficult to prove because of inconsistent results and self-reporting.

The study’s data, as indicated by the Yahoo.com report, points to clear patterns based on the time in which the responders came to ground zero on the day of the event—morning or afternoon, the next day, or one to two days after the attack. It also controls for predisposing factors such as age, high blood pressure, high blood cholesterol, type 2 diabetes, and tobacco use.

According to a comparable article about the study published the same day on the New York Post website, NYFD firefighters spending more time at ground zero in top exposure times have a higher risk of developing heart disease.

Yahoo.com noted that the research split the large study group into four arrival periods—the first being the morning of the attacks when dust exposure was at its peak, the second being the afternoon of 9/11 when the toxic dust was still prevalent but had decreased significantly, the third being the next day, and the fourth being between days three and 14.

The data, as indicated by the New York Post, appears to reveal risk for heart disease ran along a continuum with firefighters who were exposed closer to peak times and through repetitious visits to the site over six months or more were more inclined to develop problems. Ground zero was under cleanup from Sept. 11, 2001 to May 30, 2002.

Percentages of increased risk for cardiovascular 9/11 illnesses linked to arrival period at the scene of the attack on the day of the event were the most striking, according to a CNN.com report. Those first responders arriving on the morning of 9/11 when the toxic dust was at its highest have shown a statistically significant 44 percent increase in risk of heart disease, while those arriving in the afternoon of the same day showed a 24 percent increase in risk of cardiovascular illness.

Right in between those two figures are those firefighters that were present during repetitious visits to the site over six months or more. Those professional firefighters had around a 30 percent increase in risk.