MONDAY, Jan. 7, 2008 (HealthDay News) -- People with no history of heart problems who felt extremely stressed following the 9/11 terrorist attacks were prone to heart problems in the three years following the attacks, researchers report.
While extreme stress can trigger an immediate lethal heart attack in some people, it can also gradually increase the risk for heart disease over time. And stressful events may remind people of earlier stressful situations, leaving them vulnerable to health problems such as heart disease, the researchers noted.
"The 9/11 attacks represent a formidable form of stress for many people because it's an assault on their country," said lead researcher E. Alison Holman, an assistant professor of nursing science at the University of California, Irvine. "It's the first time in decades that the United States has experienced that form of collective trauma. Probably the last time was after Pearl Harbor."
Holman's team found an increased incidence of cardiovascular ailments during the three years following Sept. 11, 2001. "Those aliments include high blood pressure, heart problems and stroke," she said.
The acute stress reactions were primarily post-traumatic stress disorder (PTSD) and "disassociation," Holman said. But unlike findings in previous research, the new study found that the effect of these problems did not develop immediately after the attack, yet seemed to be enough to put people at risk for heart problems years later.
"People who experienced high levels of acute stress reaction following 9/11 had a much higher incidence of cardiovascular ailments over the three years following 9/11 than people who did not have the high acute stress reaction," Holman said.
For the study, Holman's team collected data on 2,729 adults from across the country, 2,592 of whom had completed an online health survey before the 9/11 attacks. After the attacks, the people took another online survey about their stress responses, such as anxiety, feelings of detachment from oneself or the world, or re-experiencing the event. They were later surveyed each year about their health for three years.
The researchers found that before the attacks, 21.5 percent of the people had been diagnosed with a heart problem. But three years after the attacks, 30.5 percent reported heart problems.
Those who had acute stress responses to the 9/11 attacks had a 53 percent increased incidence of heart problems over the ensuing three years. This association held true even after compensating for risk factors for heart disease, existing heart and mental health problems before 9/11, and degree of exposure to the attacks.
Also, people who had high levels of stress immediately after the attacks were about twice as likely to develop high blood pressure, and about three times as likely to develop heart problems during the following two years, the researchers found.
People who continued to worry about terrorism after 9/11 had an increased risk for heart problems two to three years after the attacks, Holman said.
The findings are published in the January issue of the Archives of General Psychiatry.
Holman said the findings may indicate the need to treat people who experience severe stress immediately after a similar attack, to prevent the development of both mental and physical problems.
"It's important that we think about not just mental health issues following a stressful event like this, but we have to consider ways that we can identify people who are at high risk for both physical and mental health disorders immediately after trauma," she said.
However, one expert thinks 9/11 was a unique event that produced a unique set of physical and mental problems, even for people not directly involved.
"This type of tragedy -- this type of assault on our country -- highlights the psychological national identity that this threat was a threat to all," said Samuel F. Sears, a professor of psychology and director of health psychology at East Carolina University.
"This is continued evidence of the powerful role of experiences on both physical and mental health interrelationships," Sears said. "But there were unique characteristics about this threat that have increased cardiovascular events."
Those characteristics include the number of people killed on 9/11, the unpredictability of the attacks, and the ongoing threat of terrorism, Sears said. "It's like a natural disaster that could occur every day without warning," he said.
For more information on post-traumatic stress disorder, visit the U.S. National Institute of Mental Health.