Vaping can lead to liver disease, suggests new research.
Researchers found that high nicotine in electronic cigarettes causes non-alcohol fatty liver diseases in mice.
In a 12-week study, researchers split mice into two groups, one were exposed to e-cigarette aerosol and the other group of mice were exposed to saline aerosol.
The researchers collected liver samples and looked at genes in the liver affected by e-cigarettes using a technique called RNA sequence analysis, which allows scientists to observe large numbers of cells.
They found changes in 433 genes that were associated with fatty liver development and progression in the mice exposed to e-cigarettes.
Study lead author Professor Theodore Friedman, of Charles R. Drew University of Medicine & Science in Los Angeles, said: "The popularity of electronic cigarettes has been rapidly increasing in part because of advertisements that they are safer than conventional cigarettes.
"But because extra fat in the liver is likely to be detrimental to health, we conclude that e-cigarettes are not as safe as they have been promoted to consumers.
"Our experimental results will provide support to policymakers and federal and state regulatory bodies to take preventive measures to stop the increasing use of e-cigarettes among both children and adults."
The study also found that genes related to the 'body clock' were changed in mice exposed to e-cigarettes, which is known to accelerate the development of liver disease including fatty liver diseases.
The researchers say the study has important public health and regulatory implications, but acknowledged that the long-term effects of e-cigarettes on liver disease, diabetes, heart disease or stroke are relatively unknown.
Their findings were due to be presented at the Endocrine Society's 100th annual meeting in the United States.