Vaping Liquids Containing Propylene Glycol and Glycerin May Cause Lung Inflammation: Study

Certain chemicals in vaping liquids may cause lung inflammation and other side effects, according to the findings of new research.

The chemicals propylene glycol and glycerin are commonly found in liquids used in some e-cigarettes, commonly referred to as e-juice. However, in a small study published this week in the medical journal Cancer Prevention Research, researchers from Ohio State University suggested they may cause users to suffer lung inflammation from vaping.

The findings come amid a national outbreak of lung illnesses and deaths linked to vaping, which has sickened more than 1,300 people nationwide, including at least 30 deaths.

Researchers conducted a pilot study using repeated bronchoscopies over four weeks among 30 adults who never smoked or used e-cigarettes, and were between the ages of 21 to 30.

Participants were recruited between 2015 to 2017, and randomized into either a control group or a four-week intervention group who used e-cigarettes containing only 50% propylene glycol and 50% vegetable glycerine. They were instructed to vape at least twice daily, taking at least 20 puffs during one hour each time.

They were given refillable tank devices with LED screens that had a puff counter to measure daily vaping and puff count. Participants sent daily puff counts to study authors. Their urine was also measured for propylene glycol to assess use.

Researchers noted daily use of e-cigarettes over one month led to some inflammation in the lungs. Inflammatory cell counts and cytokines were determined during bronchoscopy, a procedure that looks inside the lung airways.

The findings indicate the increase in inflamed cells was linked to propylene glycol. Those with greater changes in the lungs had higher levels of propylene glycol in their urine samples, indicating they inhaled more.

Prior research has provided evidence that using e-cigarettes may increase the risk of heart disease and cancer because of the exposure to carcinogenic chemicals in the vape liquid. However, studies haven’t focused directly on human lung inflammation.

In this new study, there were no significant changes in mRNA or microRNA gene expression. Additionally, the absolute magnitude of inflammatory changes was small. There was an increase, but it was still within the normal range. Researchers note that the findings are not surprising, as inhaling chemicals into the lungs will most likely have some type of impact.

As a number of JUUL vaping lawsuits are proceeding through the court system, involving both respiratory injuries and addiction problems linked to the popular e-cigarette, researchers indicate that additional studies are needed to determine how much inflammation may occur over a prolonged period of time and if prolonged exposure to the ingredients in question have a different effect, since those ingredients are often carriers for nicotine and flavorings.