Dr. Steven Lipshultz, the lead researcher, said his team was unable to find any studies of cinnamon inhalation in humans. Instead, rats breathed in cinnamon powder just one time, then were followed as they aged.
"(The) cinnamon would coat the airways and the lungs and it would lead to inflammation," Lipshultz said. "The inflammation led to scarring in the lungs, something called pulmonary fibrosis." The lung disease causes shortness of breath and chronic coughing, and can lead to hypoxia and heart failure.
Lipshultz, a professor of pediatrics at the University of Miami, says the dare is particularly dangerous for those suffering from bronchopulmonary diseases, including asthma.
Nationwide, the study found, at least 30 cases stemming from the challenge required medical attention in 2012, including ventilator support for some teens who suffered collapsed lungs.
The American Association of Poison Control Centers reported 222 cinnamon-related exposures in 2012, up from 51 in 2011, reports USA Today. So far this year, 20 exposures were reported from between Jan. 1 and Mar. 31.
Lipshultz told the Chicago Tribune the number of cases that have been reported nationwide is far less than the number of people actually the challenge.
"Those numbers relate to people intentionally calling. ... You know as well as I do that if you have a teenager or college student who becomes ill, how common is it for somebody to call a poison control center? Not that common," he said.