91色情片

AS THE old joke goes, when I read about the dangers of smoking, I gave up reading. If you are a vaper, you might feel like you want to stop reading now. Don鈥檛: you need to know this.

I am a vaper. Like many others, I used to听smoke and switched to vaping for health reasons. I plan to quit completely, but I haven鈥檛 managed it yet. I am sure vaping is better for me than smoking, but I am also sure it is worse than not vaping. I cough in the morning and feel massively addicted to the nicotine. I don鈥檛 even really know what I am inhaling. I worry that it will be hard to quit, that I am causing long-term damage to my body and that by vaping, I am susceptible to slipping back down听the slope to cigarettes. I also have the same worries for the teenagers I see coming out of school and immediately enveloping themselves in sweet-smelling clouds.

As vaping has increased throughout the听Western world, these fears have been repeated often. Part of last month鈥檚 in the UK focused on new legislation aiming to create a smoke-free generation in听part by cracking down on youth vaping. Worldwide, there have been calls for tougher regulation and more investigation into vaping鈥檚 health effects as increasing numbers of children admit to taking up the habit.

But there hasn鈥檛 been a huge amount to say听on whether fears over health effects are well-founded听鈥� until recently. Now, vaping has听finally been around for long enough for听answers to start emerging from the fog.

Modern e-cigarettes first went on sale in China in 2004. They entered the UK, US and other Western markets soon afterwards and have grown in popularity ever since. 听鈥� 7.5 per cent of the population. . Vaping among teens and young adults has rocketed, peaking at 27.5听per cent in high school students in 2019 in听the US, according to the US Food and Drug Administration National Youth Tobacco Survey. In the UK, the proportion of . This is all despite it being an offence to sell e-cigarettes to people under 18 in the UK and听under 21 in the US.

Vapes vary in design, but they all have the same听basic features: a tank for the 鈥渆-liquid鈥�, a听heating element to vaporise the liquid and a听mouthpiece to inhale the resulting aerosol. Despite the name, vapes don鈥檛 produce vapour, but rather a suspension of particles and droplets in a gas. For that reason, many health bodies prefer to call them electronic nicotine delivery systems, or ENDS. E-liquids typically contain nicotine and flavourings, as well as a听solvent to dissolve them and convey them into听the lungs. The most common solvents are听propylene glycol and glycerin.

What does vaping do in your body?

The short-term health impacts of vaping听鈥� and some potential long-term consequences听鈥� are now quite well-known. What has become clear is that they aren鈥檛 all sweetness and light. Let鈥檚 start with the e-liquid. All three of its standard ingredients can do immediate harm. Nicotine is addictive and overstimulates the sympathetic nervous system, causing the , according to the American Heart Association (AHA), which published a听scientific statement on ENDS in July. As yet, there is no听evidence of this leading directly to heart attacks or other cardiovascular problems, but chronic overstimulation of the heart is known to be a risk factor for cardiac failure.

The solvents, meanwhile, can irritate and inflame the airways. Propylene glycol and glycerin are both generally recognised as safe听by the FDA, by which it means they are non-toxic. However, manufacturers of the chemicals recommend that inhalation be avoided. Short-term exposure can lead to coughing, a sore throat and decreased lung function. Perhaps that is where my morning cough has come from. In studies on the effects听of theatrical smoke, long-term exposure听to propylene glycol is associated with听wheeziness and chest tightening.

Which flavours are worst?

Some flavourings found in vapes also ring听alarm bells for the AHA. The buttery compounds diacetyl and acetylpropionyl are . Some of the other common flavours听鈥� menthol, coffee, strawberry, chocolate, cinnamon, sweet tobacco, caramel and vanilla听鈥� contain compounds that produce inflammatory responses in cultured cells. Sweeteners including sucrose and glucose, meanwhile, are converted by heat into compounds called reactive aldehydes, which听are believed to be a leading cause of听heart and lung disease in smokers.

Vapes also chuck out some unintentional byproducts, including heavy metals released from the heating element. Some elements contain a nickel-chromium alloy: rats exposed to nicotine-free aerosols produced using these elements developed , while stainless steel elements didn鈥檛 have the same effect. Studies of people exposed to nickel and chromium compounds through their occupation show an association with increased risk of lung cancer, and nickel is听one of the few carcinogens to be found in higher amounts in some vapes than in tobacco smoke. There is also evidence that the older an element or disposable vape, the more heavy metal pollution it spews out. The 101st-to-150th puffs on a disposable produce about 60 times as much as the first 50.

Vape aerosol also delivers some of the nasties found in tobacco smoke: carbon monoxide, tobacco-specific nitrosamines and听volatile organic compounds (VOCs), such as formaldehyde and acrolein. But where data exists, it consistently shows much lower levels of exposure from vaping than from smoking, according to a 2022 review by Public 91色情片 England (PHE). I blew some vape aerosol into听my indoor air quality monitor and was pleasantly reassured by the fact that it failed to听trigger the VOC alarm, which occurs when they reach a harmful concentration.

What does vaping do to your lungs?

When it comes to identifying the relationship between vaping in general and听cancer, there are some red flags. Some suggest that vaping may produce the kinds of DNA damage, inflammation and other biological alarm bells that are known to precede a tumour. One study exposed mice to 54 weeks of vaping aerosol and found that .

Vaping vs edibles: How does the way we use cannabis alter its effects?

Edibles, vapes and joints all contain the same psychoactive compounds, but the effects they have on the body vary

However, whether these effects in animal models correspond with a risk of disease in humans isn鈥檛 yet clear (see 鈥淒oes vaping wreck your lungs?鈥�). 鈥淭he precise long-term effects of vaping nicotine will not be fully known for decades,鈥� says Wayne Hall at the University of Queensland in Brisbane. In a recent statement, the AHA points out that it took decades to establish the link between smoking and lung cancer, but vaping has only been widely practised for 10 years.

Vaping vs smoking

Nonetheless, the review by PHE answers some other important questions. It found little听evidence of toxic substances in the bodies听of vapers, with significantly lower levels听than in smokers, and often the same or听only slightly higher levels than in people who don鈥檛 smoke or vape. It also looked at biomarkers associated with cancer, respiratory and cardiovascular conditions and found the same pattern. Nor was there evidence of a risk from second-hand vape.

PHE did flag up the buttery flavourings and cinnamaldehyde (which gives a cinnamon flavour) as potentially concerning, but absolved the solvents. Overall, the review concluded, even though vaping isn鈥檛 risk-free, it 鈥減oses a small fraction of the risks of smoking鈥� in the short and medium term. This is in keeping with its earlier review, from 2015, in which it concluded that e-cigarettes are around 95 per cent less harmful than smoking.

That chimes with my experience. I have smoked. I have vaped. I have mixed and matched, and I have abstained altogether. Quitting both is obviously preferable, and I will听get there one day, but smoking feels at least 20听times worse for my health. And it stinks.

Indeed, I have much to thank my vape for. I听have successfully used it to wean myself off smoking, as have many others. According to PHE, data from smoking cessation services in听England shows that vaping is now a key weapon in the smoke-free arsenal. People who听go cold turkey have a roughly 50 per cent success rate over a four-week period from their date of quitting. Switching to a vape increases that to just over 60 per cent. Vaping plus a prescription drug (nicotine replacement therapy, or the now-unavailable bupropion or听varenicline, which were withdrawn from the听market after reports of contamination with听toxins) was even more successful.

Longer-term studies also show the relative success of vaping as a smoking-cessation tool. According to a recent review by the Cochrane Collaboration, an independent medical evidence review body, up to 14 per cent of vapers stayed smoke-free after six months, compared with 6 per cent of people using nicotine replacement therapy and 4 per cent of those receiving behavioural therapy or nothing.

But does it also cut the other way? Since vaping became popular among young people, there have been that it acts as a听gateway drug, luring them into smoking, perhaps through getting them hooked on nicotine or habituated to handling and inhaling from a cigarette-like object.

Does vaping lead to smoking?

In 2017, a team led by , now at Duke University in Durham, North Carolina, published an influential study on this pressing question. The researchers analysed the existing data on whether teenagers and young听adults who try vaping are more likely to听subsequently take up smoking. The answer was a resounding yes. Around 23 per cent of those who dabbled in vapes later took up smoking, while only 7 per cent of non-vapers did. The study accounted for other known risk factors for starting smoking听鈥� having parents, siblings or friends who smoke, and scoring high for traits like sensation seeking and risk听taking听鈥� leading Soneji and his听team to conclude that there is a 鈥渃ausal correlation鈥� between vaping and smoking.

This appeared to be confirmation of the听gateway hypothesis. But in that controlled for more risk factors, including use of alcohol and marijuana, the听correlation melted away. 鈥淢ost of the association between vaping and subsequent smoking has disappeared,鈥� says Hall.

In any case, says Hall, if the gateway hypothesis is true, then as youth vaping rises, so should youth smoking. But the opposite has听happened: the rise of youth vaping has been accompanied by a decline in youth smoking in the US, UK and New Zealand. In the听US, in 2011, 16 per cent of 15 to 18-year-olds smoked, while only 2 per cent vaped. Today, those figures have effectively reversed. 鈥淎t most, [there is] a small gateway effect that is听outweighed by the much larger number moving from smoking to vaping,鈥� says Hall.

听

Still, though, the controversy goes on. 鈥淭here isn鈥檛 yet a consensus as to whether the听use or availability of e-cigarettes causes young people to smoke who wouldn鈥檛 have otherwise,鈥� says Jamie Hartmann-Boyce at the听University of Massachusetts Amherst. 鈥淭hough young people who vape are more likely to go on to smoke than their non-smoking peers, it鈥檚 not clear if this is because听vaping causes them to smoke or if听something about people who vape听also makes them more likely to smoke.鈥�

But teen gateway or not, vaping as an adult instead of smoking appears to be doing some good in terms of cutting smoking rates. In the US, the adult smoking rate since the introduction of vapes has fallen from 21 per cent to 11 per cent. In the UK, about 13 per cent of adults smoke, half the number that did in 2005. Vapes aren鈥檛 the only factor, but, according to Hall, 鈥渢he evidence suggests that vaping is displacing smoking at a population level鈥�. In a perfect world, nobody would smoke anything. Vaping isn鈥檛 the ideal solution, clearly, but it may be an imperfect way of moving us in the right direction.

Graham Lawton is a features writer at New Scientist