E-cigarette additives increase inflammation and impair lung function, study finds

October 11, 2018, American Physiological Society
Credit: CC0 Public Domain

Flavoring and additive ingredients in e-cigarettes may increase inflammation and impair lung function, according to new research. The study, published ahead of print in the American Journal of Physiology—Lung Cellular and Molecular Physiology, also found that short-term exposure to e-cigarettes was enough to cause lung inflammation similar or worse than that seen in traditional cigarette use. The research was chosen as an APSselect article for October.

E-cigarettes, popular battery-powered devices that simulate the act of smoking a traditional cigarette, dispense a derived from liquid chemicals in a refillable cartridge. The refills typically contain , nicotine and often flavorings. Propylene glycol—a colorless, odorless food additive—is found in numerous processed food and beverages; it is also used as a solvent in a number pharmaceuticals. E-cigarette devices and refills are not well regulated, and the long-term health effects of e-cigarette use are not widely known.

Researchers studied several groups of mice that received whole-body exposure to varying chemical combinations four times each day. Each exposure session was separated by 30-minute smoke-free intervals.

  • One group was exposed to cigarette smoke ("cigarette");
  • One group was exposed to e-cigarette vapor containing propylene glycol and vegetable glycerol, an odorless liquid derived from plant oils ("propylene");
  • One group was exposed to e-cigarette vapor containing propylene glycol and nicotine ("propylene + nicotine") and
  • One group was exposed to e-cigarette vapor containing propylene glycol, nicotine and tobacco flavoring ("flavoring").

The cigarette and e-cigarette groups were compared with a control group that was exposed to medical-grade air. Some of the animals in each group were exposed to short-term cigarette smoke or e-cigarette vapor (three days), while others were exposed for a longer term (four weeks).

The research team found an increase in markers of inflammation, mucus production and altered lung function in the propylene, propylene + nicotine and flavoring groups after three days. However, the group showed fewer negative effects with long-term exposure, suggesting the additive alone elicits only a temporary irritation that eventually subsides with continued use. In addition, two inflammation-producing proteins became elevated only in the flavoring group, suggesting that some of the many flavoring components on the market may not be safe for even short-term use.

The condition of the e-cigarette groups in comparison with the cigarette group surprised the researchers. The level of oxidative stress—stress at a cellular level—in the flavoring group was equal to or higher than that of the cigarette group. However, respiratory mechanics were adversely affected only in mice exposed to cigarette smoke and not to after prolonged treatment. "The observed detrimental effects in the lung upon [] vapor exposure in animal models highlight the need for further investigation of safety and toxicity of these rapidly expanding devices worldwide," the researchers wrote.

Explore further: E-cigarette vapor slows heart rate in mice

More information: Constantinos Glynos et al, Comparison of the effects of e-cigarette vapor with cigarette smoke on lung function and inflammation in mice, American Journal of Physiology-Lung Cellular and Molecular Physiology (2018). DOI: 10.1152/ajplung.00389.2017

Related Stories

E-cigarette vapor slows heart rate in mice

November 13, 2017
Electronic nicotine delivery systems (ENDS) such as e-cigarettes, affect heart rhythm and cardiovascular function in mice, according to preliminary research presented at the American Heart Association's Scientific Sessions ...

Smoking electronic cigarettes kills large number of mouth cells

November 16, 2016
A large number of mouth cells exposed to e-cigarette vapor in the laboratory die within a few days, according to a study conducted by Université Laval researchers and published in the latest issue of Journal of Cellular ...

E-cigarette vapor disables key immune cells in the lung and boosts inflammation

August 14, 2018
E-cigarette vapour boosts the production of inflammatory chemicals and disables key protective cells in the lung that keep the air spaces clear of potentially harmful particles, reveals a small experimental study, published ...

Some e-cigarette ingredients are surprisingly more toxic than others

March 27, 2018
A new study by UNC School of Medicine researchers shows that e-liquids are far from harmless and contain ingredients that can vary wildly from one type of e-cigarette to another.

E-cigarette flavors are toxic to white blood cells, warn scientists

January 30, 2018
Sugar and spice are not so nice, at least when it comes to vaping or inhalation. Exposure to e-cigarette flavoring chemicals and liquids can cause significant inflammation to monocytes, a type of white blood cell—and many ...

E-cigarette vapor found to damage lung cells even when nicotine-free

May 26, 2015
Electronic cigarette (e-cig) use has now surpassed traditional cigarette use among middle and high school students, according to the Centers for Disease Control and Prevention. This leaves many parents, public health officials ...

Recommended for you

A co-worker's rudeness can affect your sleep—and your partner's, study finds

December 14, 2018
Rudeness. Sarcastic comments. Demeaning language. Interrupting or talking over someone in a meeting. Workplace incivilities such as these are becoming increasingly common, and a new study from Portland State University and ...

A holiday gift to primary care doctors: Proof of their time crunch

December 14, 2018
The average primary care doctor needs to work six more hours a day than they already do, in order to make sure their patients get all the preventive and early-detection care they want and deserve, a new study finds.

Teens get more sleep with later school start time, researchers find

December 12, 2018
When Seattle Public Schools announced that it would reorganize school start times across the district for the fall of 2016, the massive undertaking took more than a year to deploy. Elementary schools started earlier, while ...

Large restaurant portions a global problem, study finds

December 12, 2018
A new multi-country study finds that large, high-calorie portion sizes in fast food and full service restaurants is not a problem unique to the United States. An international team of researchers found that 94 percent of ...

Receiving genetic information can change risk

December 11, 2018
Millions of people in the United States alone have submitted their DNA for analysis and received information that not only predicts their risk for disease but, it turns out, in some cases might also have influenced that risk, ...

Yes please to yoghurt and cheese: The new improved Mediterranean diet

December 11, 2018
Thousands of Australians can take heart as new research from the University of South Australia shows a dairy-enhanced Mediterranean diet will significantly increase health outcomes for those at risk of cardiovascular disease ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.