A recent study led by researchers at UCL (University College London) and University of Innsbruck has found that e-cigarette users with a limited smoking history experience similar DNA changes to specific cheek cells as smokers. The study, published in Cancer Research, analyzed the epigenetic effects of tobacco and e-cigarettes on DNA methylation in over 3,500 samples, investigating the impact on cells that are directly exposed to tobacco (e.g. in the mouth) and those that are not directly exposed (e.g. in blood or cervical cells).
The research focused on the epigenome. The study found that epithelial cells in the mouth showed substantial epigenomic changes in smokers, which are further elevated in lung cancers or pre-cancers. Importantly, the researchers observed similar epigenomic changes in the cells of e-cigarette users who had only ever smoked less than 100 tobacco cigarettes in their lives.
While the scientific consensus is that e-cigarettes are safer than smoking tobacco, this study highlights the potential long-term risks and links to cancer. The researchers hope that their work may help form part of a wider discussion into e-cigarette usage, especially in people who have never previously smoked tobacco.
The study also found that some smoking-related epigenetic changes remain more stable than others after giving up smoking, including smoking-related epigenetic changes in cervical samples. This has not previously been studied and highlights the need for long-term studies of e-cigarettes.
The researchers involved in the latest study now hope to further investigate how epigenetic changes related to smoking in cheek swabs could be used for identifying individuals at highest risk of developing cancer and assess the long-term health risks of e-cigarettes.