A study recently published in the American Journal of Physiology warns that some additives and flavors in electronic cigarettes may be as harmful as — or even worse than — normal tobacco cigarettes. Researchers found the ingredients impaired lung function and increased lung inflammation, but the effects didn’t last long.
During the study, researchers exposed four groups of mice to four different conditions, including regular cigarette smoke, e-cig vapor with both propylene glycol and vegetable glycerol (the two main ingredients used in e-liquids), as well as vapor with propylene glycol and nicotine, and vapor with propylene glycol, nicotine, and a tobacco flavoring.
Mice from these groups were studied and the effects were compared to a control group, which was exposed to medical-grade air. The researchers found that after three days, mice exposed to all three e-cigarette vapor varieties showed increases in mucus and inflammation, as well as impaired lung function.
The team noted that the propylene exposure group had fewer unwanted effects from long-term exposure, though, indicating that it may only cause problems early on. As well, the study found that inflammation-related proteins increased only in the group exposed to flavoring, which means some flavor compounds may be harmful to lungs even with short-term exposure.
Of note, the team found that oxidative stress in mice exposed to the flavoring was equal to or even higher than that of the mice exposed to cigarette smoke. Prolonged exposure, though, only impaired the lung function of mice exposed to smoke and not vapor.