Re-posted from Harvard Health Publications
Written by: John Ross, MD, FISDA
Americans are confused about electronic cigarettes. A recent poll showed that the public was about evenly split between those who thought that electronic cigarettes, or e-cigarettes, were less harmful than conventional cigarettes, and those who believed that e-cigarettes were as bad as or worse than regular cigarettes.
Unfortunately, there is no long-term safety data about e-cigarettes. What information we do have suggests that e-cigarettes have a complex mix of potential harms and benefits.
E-cigarettes: Less deadly than regular cigarettes
First, the good news: e-cigarettes are almost certainly less lethal than conventional cigarettes. Cigarette smoking is a uniquely dangerous addiction. In fact, cigarettes might be the only consumer product that kills when used as directed. Cigarettes are the number one cause of preventable death in the United States, killing 480,000 people every year. That’s more deaths than HIV, heroin, methamphetamine, cocaine, alcohol, motor vehicle accidents, and firearms combined. Smoking increases the risk of stroke, heart attack, COPD, asthma, diabetes, and most cancers. The free radicals in cigarette smoke physically age the human body. On average, smoking reduces your life span by at least 10 years. Tobacco could not possibly be approved for sale in the United States today if it was a new product coming on the market.
A burning cigarette gives off noxious gases, such as carbon monoxide and hydrogen cyanide. Cigarette smoke also contains an ultrafine suspension of gummy residue, known as tar. Most of the carcinogens in cigarette smoke are found in the tar. The major benefit of e-cigarettes, compared to regular cigarettes, is that they do not produce the tar or the toxic gases found in cigarette smoke. An e-cigarette contains a cartridge of fluid, popularly known as e-liquid. E-liquid is made up of nicotine and flavorings dissolved in propylene glycol and glycerol. The e-liquid is superheated by a battery-powered vaporizer, converting it into a mist which is inhaled, or “vaped.”
Studies about e-cigarettes and smoking behavior show conflicting results. E-cigarettes were mildly helpful in kicking the habit in one clinical trial. In other studies, e-cigarette use did not increase quit rates, or was even associated with a higher risk of continuing to smoke. A recent review concluded that real-world use of e-cigarettes is associated with lower quit rates.
The downside of e-cigarettes
Now the bad news. Nicotine in e-cigarettes may have several negative health effects. Chronic nicotine exposure may lead to insulin resistance and type 2 diabetes, although this risk may be offset by the well-known appetite suppressant effects of nicotine. Inhaled nicotine increases heart rate and blood pressure. Nicotine is highly addictive in its own right, and it may lead to changes in the brain that increase the risk of addiction to other drugs, especially in young people. Nicotine may also impair prefrontal brain development in adolescents, leading to attention deficit disorder and poor impulse control. These potential harms of nicotine are particularly worrisome in view of soaring rates of e-cigarette use in U.S. teenagers.
The nicotine in e-liquid may also be a household hazard. Many e-liquids have candy and fruit flavoring and packaging that makes them attractive to children. Cases of nicotine poisoning from e-liquid have skyrocketed, with accidental ingestions of e-liquid by kids rising by 1,500% in the past three years.
Flavored e-cigarettes may pose another health threat. They often contain a chemical compound called diacetyl, which is associated with a rare lung disease called bronchiolitis obliterans that causes permanent damage to the bronchioles (the tiniest airways in the lungs).
Propylene glycol and glycerol, the major components of e-liquids, are not thought to be dangerous on their own. However, they may decompose when heated by the vaporizer, and be transformed into toxic compounds such as formaldehyde. This is more common with newer vaporizers that use high wattages.
What you need to know
- For people who are currently addicted to cigarettes, e-cigarettes provide a less dangerous nicotine source, without exposure to tar or most of the poisonous gases in cigarette smoke. However, it is unclear whether e-cigarettes actually help significant numbers of people to quit smoking.
- People who do not already smoke should avoid e-cigarettes. E-liquids contain nicotine, which increases the risk of high blood pressure and diabetes, as well as flavoring agents that may cause a chronic lung disease called bronchiolitis obliterans. High-wattage vaporizers may also generate significant amounts of formaldehyde and other toxins.
- E-cigarette use is soaring in young people. This is of particular concern, as exposure of the developing brain to nicotine may impair brain development and predispose teenagers to addiction to other drugs.