A new bladder cancer study reveals that vapers may be at elevated risk compared to non-smokers and never vapers. Specifically, vaping and bladder cancer may be linked, although smokers too are already known to be at risk.
Scientists conducting a recent meta-analysis of multiple research studies identified six substances strongly linked to bladder cancer in the urine of e-cigarette vapers. To conduct the meta-analysis, the team compiled results from 22 studies that analyzed urine from vapers of e-cigarettes and users of other tobacco products, including traditional cigarettes.
The idea was to uncover any evidence of cancer-linked compounds or their biomarkers and compare smoking and other tobacco consumption methods with vaping. The researchers found six compounds or biomarkers with a strong link to bladder cancer in the urine of vapers.
Smoking vs Vaping and Bladder Cancer
Various health authorities have cautioned the public about health risks of vaping, including possible risk of EVALI. However, there is no definitive safety profile for e-cigarettes like there is for traditional cigarettes. This is in part because there are so many different varieties.
“Smoking is the No.1 modifiable behavioral risk factor for bladder cancer,” study author and UNC School of Medicine said associate professor of urology Marc Bjurlin said in press materials. “There is now evolving literature showing that people who vape may have similar carcinogens in their urine as combustible cigarette users.”
However, researchers are trying to determine what qualities e-cigarettes and traditional cigarettes might share—especially since long-term effects won’t become clear for many years. To better understand these kinds of long-term risks, including cancer, the team investigated possible exposure to carcinogens specific to bladder cancer. This is important since the body may process these kinds of substances and then excrete them in urine.
The researchers identified 40 parent compounds the body can process to produce 63 different toxic chemicals. The chemicals themselves remain in the body as carcinogenic metabolites. The team compared their results with carcinogens in known databases and found six with a strong link to bladder cancer.
In some studies, the researchers found evidence that vapers had “significantly” higher levels of several carcinogens linked to bladder cancer in their urine compared to never vapers.
“This finding shows us that people who vape will be exposed to a variety of different carcinogens,” Bjurlin said in the materials. “People who have decades of exposure to these carcinogens from vaping may be at risk for developing malignancies, especially bladder cancer.”
There were some limitations to this meta-analysis. First, due to the nature of the different studies, the researchers did not always know the precise levels of all of the cancer-causing substances in the urine of users.
Some studies also included dual users, people who both smoked and vaped. Other studies included former smokers who had switched to vaping—probably a decent-sized group since many former smokers use vaping as a smoking cessation strategy.
“That made it difficult to assess whether the carcinogen found in the urine was actually from the e-cigarette use or from the cigarette use,” Bjurlin said in the materials.
The researchers next want to discover whether there is an exposure threshold for carcinogens that lead bladder cancer.