Dr José Luis Velasco warns that this smoking method will develop a new disease linked specifically to vape use.

"What we are seeing now that we didn't see 10 years ago are the respiratory symptoms associated with vaping and e-cigarettes," Dr Velasco says. For him, tobacco remains the main risk to respiratory health, but he is concerned because, often, the message behind vaping and e-cigarettes "is that they're harmless".

On the contrary, the WHO (World Health Organization) has made it clear that they cause lung damage. The type of respiratory disease, however, "will not become apparent until 20-30 years after exposure", Dr Velasco fears.

A study by the pulmonology and ophthalmology departments at the Clínico hospital, published in March in the scientific journal Tobacco Prevention & Cessation, found that a single vaping session causes measurable respiratory changes and ocular alterations.

A single exposure to vaping causes measurable changes in certain respiratory parameters. The vaping session reduced tear production in almost half of the participants. It also caused changes in two parameters relating to the circulation and structure of the macula. While the study demonstrates acute effects, it does not allow the researchers to determine whether these changes cause permanent damage.

"We'll only see a link between a disease and vaping in 20 or 30 years' time and in young people, because they're taking it up at a very early age right now. Kids are vaping at the age of 13 or 14 and that worries me," Dr Velasco says.

"The idea that inhaling this substance is harmless is simply not true. If you test these patients to assess the condition of the pulmonary basement membrane, you can see that there are abnormalities," he explains. For the time being, however, there is no disease specifically linked to vaping: "It's still too early. We need more time."

Among the consequences of bronchial inflammation, "the bronchi overreact to a stimulus that is unusual, but it is not clean air". Some people vape two or three times and "there are different habits and ways of doing it". In any case, regardless of the habit, it is clear that vaping causes damage.

In clinics, they see "patients with pneumonia and symptoms of pulmonary oedema". Although they cannot find a direct link, the patients "have a history of vaping".

"What we do see in our smoking clinics, however, are vapers who want to give up vaping, which is also a challenge for us." The approach is multidisciplinary, combining psychological and pharmacological treatments. If the vaping involves nicotine, it is treated in the same way as smoking.

The more detailed findings of the study are as follows: after 40-60 inhalations, FeNO levels fell. FeNO is a marker associated with airway inflammation. In those who smoked and vaped more frequently, peripheral airway resistance also increased.

Furthermore, vaping immediately alters tear production. This suggests an acute disturbance of the tear film.

Changes were also detected in parameters relating to the retina. After vaping, macular blood flow density and choroidal thickness in the lower part of the macula decrease significantly. The researchers interpret these changes as a possible transient retinal haemodynamic alteration.

The impact is acute, but the study does not allow determining whether it results in permanent damage. The study only had 40 participants and there was no control group. The results cannot be extrapolated to repeated or chronic use. For this reason, the authors are calling for longer-term studies.

Review public health, medical care and clinical news