(AP) -- Law enforcement officers who worked near ground zero after the World Trade Center attacks seem to show early signs of heart problems at a higher rate than would be expected for their age, a new study suggests.
Nearly half of about 1,200 law enforcement workers who went to Mount Sinai Medical Center's program in New York to monitor medical effects from the Sept. 11, 2001, terrorist attack showed some impaired heart function on ultrasound tests. The study was released Saturday at an American College of Cardiology conference.
"This is the first study to suggest a potential link between exposure to ground zero and early preclinical heart abnormalities," said Dr. Lori Croft, who led the work. Inhaling dust particles that can cause lung and heart disease may be to blame, she said.
The finding has many caveats. Researchers did not verify workers' presence at the site, and they do not know how many may have had pre-existing heart problems. Nor is there any comparison to other New Yorkers, or to police in other urban areas exposed to pollution and similar job stress.
"This could be an occupational find, or I might even have this problem because I live in New York City," Croft said.
Sicker workers also are more likely to seek testing than others who feel fine, making the portion found to have heart problems seem bigger than it may really be. The study was funded by the Fraternal Order of Police, which has encouraged workers to get suspected health issues checked.
The exams were done from January 2008 through June 2009. The study was limited to workers 40 to 50 years old because heart problems become more common after 50, Croft said. Workers with high blood pressure or heart valve problems were not included.
Among the rest, 47 percent had some degree of diastolic dysfunction - meaning the main pumping chamber of the heart does not relax properly between beats, so the heart can't fill with blood as it should. Only 7 percent of people in their 40s in the general population have this problem, Croft said.
"People that are 40 years old shouldn't have diastolic dysfunction. It means something. I don't know what it means," she said.
Previous research tied exposure to dust at ground zero to lung problems, asthma and post-traumatic stress disorder.
Jeffrey Hon, World Trade Center health coordinator for the New York City Health Department, said a city-appointed panel regularly reviews published research on health effects attributed to the attack. A registry kept by the city and the federal government is tracking the health of 71,000 people exposed to dust from the disaster.
"We're interested in looking at all studies," but each has strengths and limitations, he said.
The study follows Thursday's announcement of a settlement that could pay up to $657.5 million to more than 10,000 ground zero rescue and recovery workers. To collect, workers would need to prove they had been at the site or other facilities that handled debris, and give medical records backing their illness claims.