The research is the first to look at the net costs to society of terrorism-induced smoking in the United States after 9/11 and the 1995 Oklahoma City bombing.
Though there is a general consensus that stress is a "very large motivator for individuals to use substances," the stress effects of large-scale events on substance use has not been widely studied.
"This study provides the first unbiased estimate of the effect of stress on smoking, and the finding that there was such a big increase in smoking nationwide, seemingly due to one event, is extraordinary, and surprising,” said study author Dr. Michael Pesko, an instructor in Weill Cornell Medical College's Department of Public Health.
While the Oklahoma City bombing didn’t affect cigarette-smoking rates in the U.S., Pesko suggests that 9/11 caused a significant 2.3 percent increase nationwide.
Data from the Behavioral Risk Factor Surveillance System survey, gathered by health departments in each state and compiled into an annual report by the Centers for Disease Control, includes questions about seat-belt use, smoking and drinking habits, and doctor visits.
Pesko compared 1,657,985 responses to the survey, and extrapolated that from the fourth quarter of 2001 through 2003, when the study ended, between 950,000 and 1.3 million adult former smokers resumed smoking cigarettes, representing a 2.3 percent increase in adult smokers across the country.
"I was really surprised to find that former smokers across the nation resumed their old habit," Pesko said. "I was expecting to see impacts just in the New York City area -- or, at most, the tri-state area."
The study estimated the public cost of 9/11-induced smoking to be between $530 million and $830 million -- potentially higher if the smoking continued beyond 2003.
Pesko said the study "sheds light on a hidden cost of terrorism."
Pesko suggests updated potential public health response to future stress-inducing events, including programs that offer free nicotine replacement therapy soon after. "Another strategy would be to alert health professionals to do more substance abuse screening during regular medical appointments following terrorist attacks, or any such event that is likely to stress the nation," he said.