The epigenetics of people who use exclusively use vape pens versus cigarettes has been examined for the first time. Key epigenetic modifications were identified that were shared between vapers and smokers that are a hallmark of lung cancer.
Vaping which has been generally marketed as a less dangerous alternative to smoking, has become increasingly popular in the last few years. Some health experts argue that the popularity of the habit has additionally attracted uptake of non-cigarette smokers. As the dangers of smoking are universally apparent the explosion of vaping or electronic cigarettes (e-cigs) has arguably guaranteed their acceptance as the lesser of two evils, without rigorous scrutiny of their long-term effects. Recently, reports of vaping-related deaths and severe lung injuries in the US have become more common, leading to the long-term effects of e-cigs undergoing investigation.
Researchers publishing in the journal Epigenetics examined the DNA methylation levels of blood cells of extensively matched groups of vapers, smokers, and controls to discover if any genes were differentially expressed. By focussing on LINE-1 repeat elements (Long Interspersed Nuclear Elements) the global methylation state of the whole genome could be quickly inferred. Both vapers and smokers showed a significant loss of methylation at these LINE-1 elements compared to controls.
LINE-1 repeat elements constitute 6,000 bp sequences scattered throughout our DNA, or 17% of the human genome. These elements are heavily methylated to keep them inactive, as active LINEs may interrupt protein expression due to their ability to ‘jump’ and copy themselves into other regions of DNA. High activity of LINEs and increased insertion rates are a characteristic of many cancers, including lung cancer.
The decrease in methylation levels of LINE-1 elements in vapers and smokers points to a shared effect on health – debasing the perception of vaping as a ‘healthier’ alternative to traditional tobacco smoking. Although this research does have limitations due to the small sample size of 45 participants, which the researchers do point out, the findings should be considered seriously with follow-up genome-wide studies in larger populations.
This research encourages us to take a step back and thoroughly investigate the epigenetic and genetic effects to conclusively identify the potential risks, or most optimistically benefits, of vaping versus smoking.