E-cigarettes significantly increase the risk of developing chronic lung diseases such as asthma, bronchitis, emphysema or chronic obstructive pulmonary disease, according to the first longitudinal study of its kind.
And the risk is even greater for those who also smoke tobacco – which is by far the most common pattern among adult e-cigarette users – says the research team from the University of California, San Francisco.
Their findings, published in the American Journal of Preventive Medicine, are based on data from the Population Assessment of Tobacco and Health (PATH), which tracked smoking habits and lung disease diagnoses in over 32,000 adults in the US from 2013 to 2016.
They are unrelated, the researchers stress, to EVALI, a specific vaping-related lung disease which has killed some e-cigarette users and sent others to hospital.
Previous studies have found an association between vaping and lung disease at a point in time, but the researchers say it has been impossible to tell from these whether the disease was caused by e-cigarettes, or simply that people with lung disease are more likely to use them.
The new study overcame this by starting with people who did not have any reported lung disease, taking account of their e-cigarette use and smoking from the start, then following them for three years.
“What we found is that for e-cigarette users, the odds of developing lung disease increased by about a third, even after controlling for their tobacco use and their clinical and demographic information,” says senior author Stanton Glantz.
“We concluded that e-cigarettes are harmful on their own, and the effects are independent of smoking conventional tobacco.”
The study found that current and former e-cigarette users were 1.3 times more likely to develop chronic lung disease, while tobacco smokers increased their risk by a factor of 2.6.
For dual users – people who smoke and use e-cigarettes at the same time – those two risks multiply, more than tripling the risk of developing lung disease.
“Switching from conventional cigarettes to e-cigarettes exclusively could reduce the risk of lung disease, but very few people do it,” says Glantz.
“For most smokers, they simply add e-cigarettes and become dual users, significantly increasing their risk of developing lung disease above just smoking.”
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