Runners’ feet pounding, crowds cheering, doctors bending over the hurt or exhausted in roadside tents — these are the common images of a marathon.
But a new study by Harvard researchers shifts the spotlight to the surrounding community and identifies a little-noticed risk. It found that during marathons, road closures can delay ambulances. And elderly people living near the route are more likely to die within a month if they suffer a heart attack or cardiac arrest on race day, compared with other days.
The researchers analyzed Medicare and ambulance data from the areas surrounding 11 major marathons, including the Boston Marathon, from 2002 through 2012. In the 11 cities combined, they estimated that hosting marathons led to three or four additional deaths each year.
The study, scheduled to appear Thursday in the New England Journal of Medicine, is believed to be the first to investigate how marathons affect the health of the neighbors, rather than the runners, said the lead author, Dr. Anupam B. Jena. Its publication four days before the Boston Marathon is coincidental, he said.
“City planners and emergency medical personnel should be aware of the unintended consequences that these kinds of events have,” said Jena, an associate professor of health policy at Harvard Medical School. “Most of the preparations are around making sure participants at events have a good experience and are safe. . . . We probably never thought of what happens to people who actually need to get to the hospital.”
The study, paid for by the National Institutes of Health, did not provide separate data on individual cities, making comparisons impossible. Jena said some cities might do a better job than others.
People involved with planning for Monday’s Boston Marathon expressed confidence in the thoroughness of their efforts, asserting that the needs of the surrounding communities are taken into account.
Unlike other marathons that circle within a single city, the Boston Marathon stretches across several municipalities and occurs on a state holiday when traffic is light. Rescue workers were praised for their rapid response four years ago during the Marathon bombings.
Tom Grilk, chief executive of the Boston Athletic Association , the race’s sponsor, said in a statement that race organizers work “with public safety officials in all of the cities and towns along the course to ensure that the community at large — as well as our participants, volunteers, and spectators — is best served.”
Boston Emergency Medical Services adds ambulances on Marathon day, positioning them on both sides of the race course and around the city, Chief James Hooley said.
Ron Quaranto, chief operating officer of Cataldo Ambulance Service, which serves Newton and Wellesley, among other area communities, said that in 28 years of serving the Marathon, “I honestly don’t recall any delay in getting patients to the hospital due to the Marathon.”
Jena, the lead researcher, got interested in the topic when a traffic jam prevented him from watching his wife run a shorter race in Boston, not the Marathon. He was planning to park near Massachusetts General Hospital but could not get off Storrow Drive. That led him to wonder: During big public events, what happens to people who need to get to the hospital for emergency care?
He decided to study marathons because they cause more disruption than other events, such as Fourth of July celebrations or Red Sox games.
The researchers excluded runners and visitors from the analysis, focusing on people age 65 and older who live in ZIP codes surrounding marathon routes. The study tabulated deaths from two conditions: heart attacks, when a coronary artery is blocked or narrowed; and cardiac arrest, when the heart stops beating.
Among those who suffered a heart attack or cardiac arrest on the day of a marathon, 28.2 percent died within a month. But in the weeks before and after the marathon, only 24.9 percent died.
That difference of 3.3 percentage points is “quite large,” Jena said, comparable to the increase in deaths that would occur if people were denied needed heart medication.
The researchers also found that ambulances took an average of 4.4 minutes longer to get to the hospital when marathons were underway. The typical ambulance ride is 12 or 13 minutes, Jena said, and adding four minutes means a significant delay for people whose hearts have stopped. “For people who have cardiac arrest, minutes do matter,” he said.
About one-quarter of people in the study drove or were driven to the hospital, probably facing even longer delays. The death rate, Jena speculates, could be significantly reduced if everyone called 911 rather than driving if they need help on days when there are big public events.
The study did not prove that ambulance delays caused the additional deaths, but it discounted several other possible explanations.
The Harvard research did not collect enough data to rule out that the differences between marathon days and other days happened by chance, said James Langabeer II , professor of emergency medicine at the McGovern Medical School at the University of Texas Health Science Center, who was not involved with the study. It could be, he said, that the patients captured in the study happened to be different in some way.
Still, Langabeer, whose research focuses on timely care for heart patients, praised the study as an important contribution. “It brings a really important policy question to mind,” he said. “This is a good initial finding. But it requires further study.”
Dr. Brendan G. Carr , director of the US Department of Health and Human Services’ Emergency Care Coordination Center, said he was skeptical a four-minute delay could produce such a large increase in deaths.
But he said the study points to the challenges of being ready for all kinds of unforeseeable events, not just what’s expected.
“This is a mass gathering event after 2001. They weren’t poised for cardiac arrest — they were poised for trauma,” he said.
Marathons in Chicago, Honolulu, Houston, Los Angeles, Minneapolis, New York, Orlando, Philadelphia, Seattle, and Washington, D.C., as well as Boston, were included in the study.
In Newton, the city is split in half by the Marathon, but Quaranto of Cataldo Ambulance said that doesn’t change the ambulance routes. Marathon or not, patients on the north side go to Boston hospitals, and patients on the south side go to Newton-Wellesley Hospital. More than 20 ambulances — quadruple the normal contingent — are positioned around Newton and Wellesley on Marathon day, he said.
Newton-Wellesley Hospital is the only hospital directly on the Marathon route, its usual entrance blocked. Ambulances merely approach from a different road, said Charlotte Roy, emergency management coordinator.
“We have not had any issues with patients getting here,” she said.
Felice J. Freyer can be reached at email@example.com.