Analyzing Breath Shows How Smoking, Vaping and Marijuana Affect Airway Health
An interdisciplinary study conducted by the University of California, Davis, College of Engineering and UC Davis Health reveals that cigarette smoke has a greater impact on airway health than marijuana or vaping.
The study analyzed metabolites, or molecules produced by cellular chemical reactions, from the exhaled breath of participants to analyze how airways responded. The researchers found that tobacco smoke, in particular, increased inflammation and oxidative stress. Their paper was published in Respiratory Research.
The study — the first of its kind in humans — recruited 254 participants, with 132 using a tobacco or marijuana product, sometimes both. The researchers collected exhaled breath condensate, which is the fog people see when they breathe on a mirror.
From there, the team used mass spectrometry to analyze the oxylipin content in the collected condensate. Oxylipins are lipid-based signaling molecules often associated with inflammation and oxidative stress. The researchers found these metabolites were significantly upregulated in tobacco smokers, meaning they increased in activity. The oxylipin responses were less dramatic in participants who vaped tobacco products. For marijuana smokers, the oxylipin profiles were much closer (but not identical) to non-users.
It is the latest effort in a 20-year collaboration between UC Davis pulmonology researchers and the engineers who helped develop the devices used to isolate the breath condensate.
“We came up with a way to collect exhaled breath condensate in a way that provides enough volume to analyze it,” said Cristina Davis, co-senior author on the study, professor of mechanical and aerospace engineering and associate vice chancellor for research. “To collect it, we had people exhale through a long glass tube that's cooled with dry ice, and that condenses those particles for collection.”
Using this non-invasive approach, the team has been collecting so-called breath libraries for about five years to better understand asthma and other conditions.
“Our question in the current study,” said Davis, “is how the biology is altered when people make lifestyle choices like smoking or vaping.”