Studies in the U.S. have documented a substantial short-term psychological response to the 9/11 attacks but their effect on physical health has received little attention. Extremely stressful events can increase people's risk of cardiovascular problems and in the weeks following 9/11 rates of heart problems increased significantly in New York City and the surrounding areas and comparable findings were reported in Florida suggesting that direct exposure to the attacks wasn't necessary to precipitate health problems. A U.S. study of people who had completed a health survey before 9/11, a web-based assessment of their stress levels 9-14 days after the attacks and follow-up surveys 1, 2 and 3 years later found that acute stress responses to the attacks were associated with a 53% increased incidence of cardiovascular problems over the following three years even allowing for other factors such as smoking, body mass index and diabetes. Individuals reporting high levels of acute stress immediately following the attacks reported an increased incidence of heart problems and high blood pressure. Among people reporting ongoing worry about terrorism after 9/11 high 9/11 related acute stress symptoms predicted an increased risk of heart problems 2-3 years after the attacks.
Holman, E. Alison ... [et al] - Terrorism, acute stress, and cardiovascular health : a 3-year national study following the September 11th attacks Archives of General Psychiatry January 2008, 65(1), 73-80