New research from the Tobacco and Alcohol Research Group (TARG) at the University of Bristol's School of Psychological Sciences has been described as " very interesting " by harm reduction expert Dr Sarah Jackson. The team used a method called Mendelian randomisation to find out the actual facts about the level of risk posed by regular nicotine use - and the answer is very positive.
If Dr Sarah Jackson says the results of a research project are " very interesting ", then they really are. Dr Jackson is a principal investigator at the Alcohol and Tobacco Research Group at University College London, where she specialises in evaluating the effectiveness of smoking cessation methods, including assessing the practical effectiveness of all the major smoking cessation aids. This includes analysing the impact of e-cigarettes, a topic she regularly discusses with peers at conferences. She is also a member of the Action on Smoking and Health Advisory Committee, the London Transformation Programme Board, and editor of the research journal Addiction .
Bristol Tobacco and Alcohol Research Group This month, the team published " Evaluating the health effects of nicotine exposure by analyzing the effects of nicotine and non-nicotine components of tobacco smoke: a multivariable Mendelian randomization study." The work of Marcus Munafò , a well-respected scholar in the field of e-cigarette and tobacco harm reduction research projects.
They say the effects of smoking are well known, but the effects of regular nicotine use (not in combination with other combusted tobacco products) are far less clear. With millions of people now vaping every day and using the devices for years, they say it is " increasingly important to understand and separate the effects of nicotine use from those of tobacco smoke exposure ."
But they noted that it was " difficult to separate the effects of regular nicotine use from those of smoking ".
Professor Michael Russell is regarded as the father of the concept of tobacco harm reduction – so important that he was posthumously awarded an award named after him . In 1976 he wrote: “ People smoke for the nicotine but die from the tar ” and went on to advocate that the relationship between tar and nicotine could play a fundamental role in making cigarettes safer – particularly in developing low-tar cigarettes.
With the advent of e-cigarette devices in the early 2000s, he said, “ there is no reason not to encourage people to switch from tobacco products to less harmful nicotine delivery systems .”
That’s what the Bristol research team was thinking: Can we prove that nicotine doesn’t cause harm to our health?
Dr Jasmine Khouja , corresponding author of the study, explained their work: " There is a lot of research on how nicotine affects health. Most of these effects are short-lived, such as increased heart rate and blood pressure, which quickly return to normal.
Clinical trials using nicotine patches have also shown that short-term use is safe, but we know less about the health effects of long-term, regular nicotine use.
“Most of what we know comes from animal studies and studies of smokers. This is problematic because we don’t know if humans will respond in the same way as animals, and in studies of smokers we can’t easily separate the effects of nicotine from the effects of other ingredients in cigarettes .”
People who use patches, sprays or gum tend to use them only while they are trying to quit and stop quickly when they think they have escaped the clutches of tobacco.
For e-cigarette users, it’s a completely different ball game.
E-cigarettes work because they mimic many of the actions of smoking and allow adults to use their devices until their brains register that nicotine levels in their blood have reached the appropriate level (called self-titration). People can adjust how often they use their devices by changing the nicotine content in their e-liquid or the amount of vapor inhaled into their lungs, i.e., e-liquids with higher nicotine concentrations or e-cigarettes inhaled directly into the lungs can reduce the number of inhalations.
Because of the similarities between smoking and vaping, the convenience of substitution means that ex-smokers continue to use e-cigarette devices long after they stop using patches, sprays or gum.
"We used genetics to try to separate the health effects of nicotine from the effects of other substances in cigarette smoke," said Dr. Khouja. " We found that nicotine does not cause the adverse health conditions seen in smokers: poor lung function, chronic obstructive pulmonary disease, lung cancer and coronary heart disease. However, it does increase heart rate ."
To help people understand the Mendelian randomization process the team used, she referred interested readers to a 2-minute introductory guide on YouTube .
“ Mendelian randomization studies the association between a gene and an exposure (e.g., nicotine use) and an outcome (e.g., cancer) to understand if a causal relationship exists and to account for confounding factors. Confounding occurs when factors other than the studied exposure (e.g., nicotine exposure) influence the outcome. Confounding factors can make it difficult to determine true cause-effect relationships, ” continued Dr. Khouja.
"Our genes are randomly inherited from our parents and do not change even if we are exposed to confounding factors. Researchers use genetics as a proxy for exposure in MR, arguing that any differences in health outcomes are related to the specific factor they are studying. Using an extension of MR, multivariate MR, we can look at two exposures at the same time that have a common genetic cause and further account for confounding factors. This allows us to understand if they both have an effect or if only one of them is truly causing the outcome ."
What did they find in the end?
The study authors concluded: " We found that nicotine does not appear to be an independent cause of poor lung function, lung cancer, chronic obstructive pulmonary disease, or coronary heart disease, but does increase heart rate. These results support previous evidence that nicotine itself does not directly cause adverse health outcomes ."
This is good news for those who are concerned about their relatives using safer nicotine products such as e-cigarettes.