In March 2026 we affirmed, after an extensive assessment of the animal and human laboratory-mechanistic evidence, that e-cigarettes are likely to cause oral and lung cancer. The immediate response has been ‘how dangerous are they?’ and ‘surely, they must be safer than smoking?’. There is an overwhelming need to augment our qualitative statement with quantitative data. Using tobacco epidemiology as an analogous example, it took almost 100 years to prove that smoking caused lung cancer (1860-1964) and another 50 years, to 2010, to determine the full extent of the hazard. While our assessment of carcinogenesis was reached 20 years after e-cigarettes were introduced, saving a lot of time.
On the grounds that we should not have to wait all this time to decide on what to do, this presentation focuses on what we know about the evolution of tobacco hazards, and what this could mean for e-cigarette use, and provide new data on risks of starting cigarette smoking at a young age and the benefits of quitting as late as after a cancer diagnosis.
The final section offers practical recommendations for clinical health systems to record smoking information effectively and outlines low-cost, timely epidemiological study options using death notifications to generate early-onset local evidence for prevention, rather than relying on cohort studies that can take decades to mature.