Second hand smoke can cause skin diseases

Second-hand smoke, or THS, consists of residual pollutants from tobacco smoke that remain on surfaces and in the dust after tobacco is smoked. It can remain on indoor surfaces indefinitely, causing potentially harmful effects on both smokers and non-smokers.

A team led by researchers from the University of California, Riverside, found that acute exposure to the skin to THS increases biomarkers associated with the onset of skin diseases such as contact dermatitis and psoriasis.

“We found that human skin exposure to THS triggers inflammatory skin disease mechanisms and increases urinary biomarkers of oxidative damage, which can lead to other diseases such as cancer, heart diseaseand atherosclerosis,” said Shane Sakamaki-Ching, a former UC Riverside graduate student who received his PhD in cell, molecular and developmental biology in March 2022. “It is alarming that the acute effects of THS on the skin mimic the harmful effects of cigarettes to smoke.”

A study published in eBioMedicineit is the first to be conducted on people who have been dermally exposed to THS.

The clinical trial, which took place at the University of California, San Francisco, involved 10 healthy non-smokers between the ages of 22 and 45. For three hours, each participant wore THS-impregnated clothing and walked or ran on a treadmill for at least 15 minutes each hour to induce sweating and increase THS absorption through the skin. Participants were unaware that the clothing had THS. Blood and urine samples were then collected from participants at regular intervals to determine protein changes and markers of THS-induced oxidative stress. Control exposure participants wore clean clothing.

“We found that acute exposure to THS caused an increase in urinary biomarkers of oxidative DNA damage, lipids, and proteins, and these biomarkers remained elevated after the exposure stopped,” said Sakamaki-Ching, now a research scientist at Kite Pharma in California, where he leads a team of stem cells. “Cigarette smokers show the same increase in these biomarkers. Our findings may help clinicians in the diagnosis of THS-exposed patients and develop regulatory policies related to the remediation of THS-contaminated facilities.”

Prue Talbott, a professor of cell biology in whose lab Sakamaki-Ching worked, explained that the skin is the largest organ that comes into contact with THS and therefore may be most affected.

“There is a general lack of knowledge about the human health response to THS exposure,” said Talbot, the paper’s corresponding author. “If you buy a used car that was previously owned by a smoker, you are putting yourself at some health risk. If you go to a casino where smoking is allowed, you are exposing your skin to THS. The same goes for staying in a hotel room that was previously occupied a smoker.”

The exposure of the 10 participants to THS was relatively brief and did not cause any visible skin changes. However, molecular biomarkers in the blood, which are associated with the early stage of activation of contact dermatitis, psoriasis and other skin diseases were increased.

“This underscores the idea that exposure to THS in the skin may lead to the molecular initiation of inflammation-driven skin diseases,” Sakamaki-Ching said.

Next, the researchers plan to evaluate residues left by e-cigarettes that may come into contact with human skin. They also plan to evaluate a larger population exposed to longer periods of cutaneous THS.

Sakamaki-Ching and Talbott were joined in the study by June Li of UCR, Suzanne Schick of UC San Francisco, and Gabriela Gregoran of UC Davis.