Electronic cigarette users' urine contains more heavy metals, as well as signs of exposure to carcinogens and other irritating chemicals than non-vapers pee, suggesting that the habit may pose serious health risks. At the same time, vapers who completely changed cigarettes still had lower levels of these substances in their urine than smokers, according to new research.
The study, published today in the journal JAMA Network Open, did not measure exposure risks directly – only the materials that the participants issued. But the findings may help in the current debate over whether electronic cigarettes are safer than cigarettes. After all, this is an important selling point for the vape industry, which markets electronic cigarettes as a less risky alternative. The problem is that they are not yet regulated, so we are not sure which chemicals contain or what the long-term effects of these products might be on health.
It is important to find out: about 6.7% of adults reported using electronic cigarettes in the last 30 days in a recent study and 3.6 million high school students in the US are vaping, according to the CDC. That's where today's study comes in. Researchers led by Maciej Goniewicz, a tobacco researcher at Roswell Park Comprehensive Cancer Center, analyzed questionnaires and urine samples sent by more than 5,100 people between 2013 and 2014 to try to detect patterns of chemical exposures in your pee.
It's a massive study, and that's why it's important, says Gideon St. Helen, a tobacco researcher at the University of California, San Francisco who was not involved in the research. "You do not have many major studies like this that looked at the use of electronic cigarettes, use of tobacco and double-use cigarettes, and have biomarkers data for all these people," he says. "It's a very thorough job," agrees Robert Strongin, an organic chemist at Portland State University, who was not involved either. But he fears people will see the results and find that electronic cigarettes are safe. In fact, Strongin comes to the opposite conclusion. "It confirms that they are not as safe as people say. We just do not know as insecure they still are.
Today's article comes from the long-term, massive Tobacco and Health Population Assessment (PATH) study that examines the use of cigarettes and electronic cigarettes in the United States. Most users of electronic cigarettes in the study, the researchers found, were former smokers who had given up a few years before enrolling. People who used both, known as dual users, smoked more or less the same amount of cigarettes as smokers, but they steamed less than the vapors.
CDC scientists have scanned urine samples from 50 biomarkers known to appear in tobacco users, including compounds produced when the body breaks down nicotine. Researchers searched for heavy metals and markers of carcinogenic substances that could increase the risk of cancer. They also tested the signs of exposure to chemicals linked to heart attacks and irritated airways. The researchers compared the levels of these toxic substances in pee to cigarette smokers, e-cigarette smokers, people who use both, and people who do not use either.
Unsurprisingly, non-smokers and non-smokers showed the lowest levels of these toxic chemicals in their pee. People who used e-cigarettes had about 19% more lead, 23% more cadmium with heavy metals, 20% more pyrene (a biomarker of carcinogens linked to heart attacks) and 66% more acrylonitrile in urine. Safety information for persons working with acrylonitrile says: "Toxic if inhaled; May cause respiratory irritation; May cause cancer; Suspected of impairing fertility or fetus. "People who took vapors every day had higher levels of these substances than people who smoked from time to time.
Compared to cigarette smokers, the vapers did a little better, but not at all. Vapers had similar levels of heavy metals – except cadmium – as smokers. Of course many of the vapers were ex-smokers and as heavy metals stayed in the body for so long these metals could just be remnants of their smoking days. Smoking cigarette pee also showed similar exposures to three volatile organic compounds: toluene, benzene and carbon disulfide. Chemists take serious precautions to avoid inhaling these things in the laboratory. Safety information for people working with carbon disulfide, for example, says "Danger! This substance has caused reproductive and fetal adverse effects in animals …. Harmful if swallowed, inhaled or absorbed through skin. Bad smell. May cause effects on the nervous system. "
When people used e-cigarettes instead of smoking, they were exposed to lower levels of all other chemicals, including nicotine. This is surprising until you remember that study participants sent pee samples between 2013 and 2014. That's before higher dose nicotine salts products like Juul take off. "These great studies take time," St. Helen says. "Real life moves much faster than these studies could actually keep up."
Here's the really amazing thing: users of electronic cigarettes have been exposed to lower levels of these substances only if they adhered exclusively to e-cigarettes. People who used it both E-cigarettes and cigarettes did not reduce their risk. In fact, these dual users showed higher nicotine levels and many of the toxicants, including two heavy metals and some of the carcinogens. This is worrisome because more than half of users of electronic cigarettes are dual users, according to a report from the CDC in 2016. "It's amazing that they have seen significantly higher levels of almost all the biomarkers they measured," says St Helen.
There are some limitations to the study. First, it considers only the toxics that are known to be from tobacco, and it makes sense that electronic cigarettes expose users to less of these things. The ingredients are different, but there may be potentially risky chemicals unique to the net nicotine prescription of electronic cigarettes that public health researchers do not know how to look for. A recent study reports that irritant chemicals can form when the ingredients in vape juice mix in the bottle, for example. "You're not looking at the other side of this.What are the toxins in electronic cigarettes that are not in the cigarette?" "You're starting from two different places," Strongin says.
Of course, looking for toxic substances unique to electronic cigarettes may be easier said than done because there are no great indicators for them, says St. Helen. For example, small amounts of formaldehyde have been detected in electronic cigarette and vapor cartridges, but there is no easy way to test exposure to formaldehyde, he says. "That's a problem, and that's why they focus heavily on the toxics of fuel cigarettes."
Although we know that users of electronic cigarettes are being exposed to some of these chemicals, we do not necessarily know if those levels are high enough to cause lifelong worry. "That's the biggest question that, with this study, unfortunately we do not have the answer now," says Goniewicz. The risk depends on the dose: inhaling the water is fatal if you inhale enough. And for some of these chemicals, this risk may accumulate over time for people who start attacking at an early age and continue vaping for the rest of their lives. That is why, from now on, Goniewicz and his team want to look for signs of health problems such as inflammation markers, not just the chemicals that can contribute to them.
Still, the starting point is that vaping is probably less risky than smoking. ("It would be almost impossible – if you tried – to make a legal product that was less safe than a cigarette, "says Strongin. But vaping is only less risky than ordinary cigarettes if people trade completely to electronic cigarettes, the study says. Using both can actually increase the health risks. And vaping is certainly certainly riskier than inhaling absolutely nothing. "If you do not smoke, do not use electronic cigarettes because you may be exposed to toxic substances," says Goniewicz. "If you are a smoker and consider using electronic cigarettes as a method of dropping out or reducing your health risk, you have to change completely."