In the past 20 years, the number of people who smoke cigarettes in the UK has steadily fallen year on year. According to data from theNHS around 28 per cent of UK adults were smokers in 1998; as of 2017, that figure had dropped to just 14.9pc. To some degree, the drop can be attributed to various legislative moves, designed to persuade smokers to kick their habit. These include the Tobacco Advertising and Promotion Act 2002, which banned the direct and indirect advertising of cigarettes, and the Health Act 2006, which prohibited smoking in public places. While the number of people smoking cigarettes has clearly decreased, that isn’t to say that people have turned their backs on smoking altogether. Since the early 2000s, more and more people have taken up vaping instead. It's a trend reflected by a new study from the University of Michigan, which shows that in the US, the percentage of 17-18-year-olds vaping rose from 11pc to 21pc between 2017 and 2018. Researchers said that more teens of all ages are vaping nicotine. Looking at the wider market, cccording to market research group Euromonitor, around seven million people around the world were using e-cigarettes in 2011, compared to 41m today. In the UK, government statistics suggest that around 6pc of the country’s adult population use e-cigarettes. Adults aged 25-34, and 35-49 are the most likely to vape, with 8pc and 7pc doing so respectively. The effects include addiction, priming for use of other addictive substances... and mood disordersVivek Murthy, former US surgeon general For e-cig users, vaping is seen as a less dangerous alternative to traditional cigarettes: NHS data shows that 48pc of users are vaping as a precursor to giving up smoking, while 30pc say they do so because they believe there are less health risks associated with the practice compared to smoking. That belief is confirmed – to an extent – by research into the effects of vaping. However, a growing body of scientific work is throwing light onto the health consequences of e-cigs – and the research suggests that it is far from a guilt-free habit. You may not need a lighter to drag on an e-cig, but it seems the old adage holds true: there can be no smoke without fire. What is vaping? Vaping is the practice of smoking electronic cigarettes (known as e-cigarettes). The products work by heating a liquid solution (often referred to as an e-liquid) to form a vapour which the user inhales. Ordinarily, that solution is made up of nicotine, flavourings, and a liquid called propylene glycol and/or glycerine, which acts as a solvent but also helps to thicken the vapour produced by the device. The idea is that an e-cigarette contains the addictive element of a cigarette (nicotine) without containing tar or producing carbon monoxide, which are heavily linked to lung disease and cancer. The thinking goes that e-cigarettes allow smokers to get their nicotine fix in a manner that is healthier than cigarettes, and hopefully help them to quit entirely. Is vaping safe? Public Health England and the NHS both recommend using e-cigarettes to help give up smoking. Advice from both bodies mentions that e-cigarettes lack many of the ‘harmful effects’ associated with smoking. It is certainly true that e-cigarettes do not contain tar and do not burn to produce carbon monoxide. This mitigates the risk of contracting cancer or other lung-related conditions such as emphysema. However, the trouble with vaping is that since the technology is reasonably new, the long term effects of using e-cigarettes is unknown. As it stands, most of the fatalities and medical emergencies associated with e-cigarettes come from the risk of them overheating or exploding and causing burns and other injuries. This is often caused by malfunctioning lithium-ion batteries within poor quality e-cigarette products. Is vaping safe... for children? One of the major areas of concern is around children and young people vaping. While the consensus is that vaping is a positive decision for those who want to give up smoking traditional cigarettes, there is a growing trend for young people to take up vaping as a lifestyle choice. This year a study from the University of Michigan found that across the US, more teens than ever are vaping. 6.1pc of 13-14-year-olds, 16pc of 15-16-year-olds, and 21pc of 17-18-year-olds said they'd used an electronic cigarette in the last 30 days, according to the survey. It's also noteworthy that these are just the young people who admitted to vaping nicotine; marijuana vaping is also on the rise. Richard Miech, the survey's lead author, commented:"Vaping is reversing hard-fought declines in the number of adolescents who use nicotine." The Monitoring the Future study surveys 45,000 American students every year and this marks the biggest single-year increase in its history, even surpassing even a huge surge in marijuana smoking in the 1970s. A 2015 study from Liverpool John Moores University found that one in five teenagers aged between 14 and 17 had tried e-cigarettes. Of those, 40pc had either never smoked before or had tried it and didn’t like it. The worry is that e-cigarettes are acting as a gateway drug of sorts. Young people get addicted to the nicotine in e-cigarettes, and then go on to take up smoking as a result. Getting addicted at that earlier age can also lead young people to become more likely to take risks and abuse other substances. Thankfully, this isn’t a serious problem for the UK just yet. A 2017 survey from Public Health England found that only 3pc of young people aged between 11 and 16 vaped regularly. Of those, the vast majority were already smoking anyway. Of those who’d never smoked, between 0.1pc and 0.5pc had taken up vaping, said the survey’s authors. Ultimately, basically every study into the matter confirms that vaping is vastly less dangerous than smoking. However, as scientists and researchers begin to conduct more studies into the potentially harmful effects of vaping, a clearer pictures of risks and benefits of using e-cigarettes is becoming clearer. In the UK, people aged 25-34 or 35-49 are most likely to vape Credit: Jason Lee/Reuters Immune system damage and lung disease According to a 2018 study from scientists at the University Of Birmingham, vaping damages immune cells in the lungs, preventing them from being able to clear harmful bacteria. The study suggests that the vapour from an e-cigarette leaves the user’s lungs in a similar condition to a cigarette smoker’s. It also found that the vapour can trigger chronic obstructive pulmonary disease (COPD). This is an overarching term for diseases including severe bronchitis, asthma and emphysema. To find this, the scientists behind the study took samples of lung cells from eight non-smokers with no history of lung disease. These samples were exposed to varying levels of e-liquid and condensed vapour. The researchers found that the vapour boosts production of inflammatory chemicals in the lungs. Not only that, but it also disables lung cells which are designed to flush harmful particles out of the lungs. Raised risk of cancer and heart disease While vaping is often marketed as a safer alternative to smokingr, one recent study suggested that many of the same risks are present in both. Researchers from the New York Society Of Medicine conceded (as so many others have) that vaping is significantly less harmful than smoking, but shared research which suggests that some of the same diseases and illnesses could affect vapers as smokers. After exposing cell samples to the vapour from e-cigarettes for ten years, the scientists looked for DNA mutations in cells from animals and humans. They found that e-cigarette vapour damages DNA and prevents the genetic code from repairing itself. This is because the nicotine in e-liquids break down into nitrosamines which are carcinogenic (cancer causing) chemicals. In short, this means that there is a possibility that vaping could contribute to lung and bladder cancer. The study also mentions vapers have a higher risk factor for heart disease. Researchers concluded: “Based on these results we propose that e-cigarette smoke is carcinogenic and that e-cigarette smokers have a higher risk than non-smokers to develop lung and bladder cancer and heart disease.” Addictive to children While e-cigarettes do not contain many of the harmful chemicals found in cigarettes, the e-liquids inside them do contain nicotine. As mentioned above, this can help smokers to cut out cigarettes without giving them cravings for nicotine, which is a powerfully addictive substance. Still, an addictive substance isn’t necessarily a problem if there’s nothing harmful in the thing you’re getting addicted to, right? The former US surgeon general, Vivek Murthy would disagree. In 2016, the top doctor issued a strongly worded report on the matter in which he warned that exposing developing brains to nicotine can lead to potentially harmful consequences. He wrote: “The effects include addiction, priming for use of other addictive substances, reduced impulse control, deficits in attention and cognition, and mood disorders.” In addition, Murthy expressed concerns that young people taking up vaping as a fashion statement would lead to increased cigarette usage later in life. As a result of these harmful effects, Murthy argued, no one under the age of 25 should take up vaping and the practice should be discouraged by parents, teachers, and carers. This pronouncement came on the back off a UK based study in North West England which also found that young people who vaped were more susceptible to other forms of substance use and risk-taking behaviours. Still much we don’t know In 2016, Researchers from Imperial College London shared a report which suggested that it could be ten or twenty years before the full effects of of e-cigarettes become apparent. The report did openly state that the likelihood of vaping being worse for people than smoking was deeply unlikely, but warned that those who took up the practice were “taking a bet”. They were particularly concerned about the rise in people who had never smoked before but had taken up vaping. The worry of popcorn lung This particular study was less concerned by the e-cigarettes themselves, or even the nicotine in the liquid, but the flavourings used to give vapes a unique taste. Specifically, the chemical Diacetyl, which is often used in food as a butter substitute, was the centre of the controversy. The chemical was used in around 75pc of all flavoured e-liquids but is thought to cause inflammation, scarring and constriction of the tiny airways in the lung known as bronchioles, reducing air flow when inhaled, though it is thought to be safe to eat. Several factories which used the chemical to make microwave popcorn were investigated by the United States National Institute for Occupational Safety and Health, which found that workers developed bronchiolitis obliterans after inhaling Diacetyl for a long time. Researchers then looked into other places the chemical was used and found that the vast majority of e-liquid producers put it into their solutions. Diacetyl was subsequently banned for use in e-liquids by the UK government in 2017. It remains in use in other countries around the world though. 20 microchanges that could make a major difference to your health in 2018 Still better than cigarettes In 2015, PHE, King’s College London and Queen Mary London shared a joint report which argued that vaping is around 95pc less dangerous than smoking. Their research admitted that there were potential dangers around vaping, particularly with regards to the chemicals used to flavour the e-liquid. However, the group argued that in comparison to the risks around smoking, e-cigarettes caused “a fraction of the harm”. The report estimated that if every smoker in Britain switched to vaping, around 75,000 lives would be saved every single year. In addition, the report suggested that e-cigarettes, once regulated, should be offered by the NHS to anyone looking to give up smoking. Toxic to bystanders As mentioned above, one of the reasons why vaping became so popular in the first place was due to the Health Act 2006 which banned smoking in enclosed public spaces such as pubs, restaurants, and trains. In contrast, vaping offered a quick, easy way to get a nicotine hit without the need to get up and go outside. However, according to a report from the World Health Organisation in 2014, second-hand vaping might have harmful effects just like second-hand smoking. It encourages governments to ban vaping indoors just like smoking. So far, no federal governments have taken this advice, but individual organisations and various local and state governments have banned the practice in certain areas. The report says: “The fact that (e-cigarettes) exhaled aerosol contains on average lower levels of toxicants than the emissions from combusted tobacco does not mean that these levels are acceptable to involuntarily exposed bystanders.” "In fact, exhaled aerosol is likely to increase, above background levels, the risk of disease to bystanders, especially in the case of some (e-cigarettes) that produce toxicant levels in the range of that produced by some cigarettes."