While definitive long-term human studies are still ongoing due to the relatively recent widespread use of electronic cigarettes, current evidence indicates that e-cigarette aerosol contains substances that are carcinogenic and can contribute to cancer risk. They are not considered risk-free, although they generally expose users to fewer and lower levels of many of the toxicants found in combustible cigarette smoke.
Carcinogenic Compounds in E-cigarette Aerosol
The aerosol (commonly misperceived as “vapor”) produced by e-cigarettes can contain several harmful and potentially carcinogenic substances, including:
- Formaldehyde and Acetaldehyde: These are known human carcinogens. They can be formed when the e-liquid solvents (propylene glycol and glycerin) are heated, especially at high temperatures or with certain device characteristics.
- Acrolein: A potent respiratory irritant and carcinogen, also formed from the heating of glycerin.
- Volatile Organic Compounds (VOCs): Other VOCs, such as benzene (a known carcinogen), have been detected in some e-cigarette aerosols.
- Heavy Metals: Traces of metals like nickel, lead, chromium, and cadmium have been found in e-cigarette aerosol. These can leach from the heating coil and other components of the device and are classified as carcinogens.
- Nitrosamines: Tobacco-specific nitrosamines (TSNAs), which are potent carcinogens, have been detected in some e-liquids and aerosol, though typically at much lower levels than in traditional cigarettes.
- Flavoring Chemicals: Some flavoring chemicals, while safe for ingestion, may produce toxic or carcinogenic compounds when aerosolized and inhaled. For example, diacetyl, linked to lung disease, has been found in some e-liquids.
Understanding the Cancer Risk
The primary concern is that chronic exposure to these carcinogens through inhalation can lead to DNA damage, inflammation, and other cellular changes that increase the risk of developing cancer, particularly in the lungs, but potentially also in other organs like the bladder and oral cavity.
While many public health bodies suggest that e-cigarettes are likely less harmful than smoking traditional cigarettes, this does not equate to them being harmless. For individuals who do not smoke, initiating e-cigarette use introduces exposure to carcinogens and other toxicants, thereby increasing their potential cancer risk compared to non-use.
In summary: E-cigarettes can expose users to carcinogenic substances, and while the overall cancer risk may be lower than that from smoking combustible tobacco, a risk does exist and is an area of active research. The long-term consequences are not yet fully understood.
