September 05, 2019
Vaping may impair the ability of immune cells in the lungs to fight infections like influenza, even from e-cigarette products that do not include nicotine or THC.
A study published Wednesday in the Journal of Clinical Investigation found that chronic exposure to the e-cigarette vapor clogs white blood cells with fat particles, reducing their ability to fight pathogens.
The study comes as the U.S. Centers for Disease Control and Prevention is investigating at least 215 cases of severe lung disease tied to vaping. Cases have been reported in 25 states. Two people have died.
Many of those cases – including one death – reportedly involved THC, the psychoactive compound found in marijuana. But health officials have not announced any conclusions from their investigations.
"At the time we were working on our study, there were one or two reports out there describing people who had vaped and had sterile pneumonias," Dr. Farrah Kheradmand, the study's senior author and a professor at Baylor University's College of Medicine, told NBC News. "The reports showed straining of cells within the lung that looked identical to what our mice had."
As part of the study, researchers exposed three groups of mice to traditional cigarette smoke, e-cigarette vapor containing nicotine and e-cigarette vapor without nicotine for four months. A fourth group of mice was exposed to natural air.
The two mice groups exposed to vapor had immune cells clogged with fat particles known as lipids. The other groups did not experience that change. When researchers then exposed the mice to influenza, those exposed to vapor developed enhanced lung inflammation and tissue damage.
Last week, the CDC issued a health advisory recommending that anyone concerned with the risks of severe lung disease refrain from using e-cigarettes until its investigation is complete.
More than 3.6 million U.S. youth, including 20 percent of high school students, used e-cigarettes last year, according to the CDC. The U.S. Food and Drug Administration has taken steps to reduce underage use.
Earlier this week, Michigan became the first state to ban the flavored e-cigarettes popular with youth.