Smoking before age of 18 increases risk of developing respiratory symptoms after 20 years: Study

People who started smoking under the age of 18 are more likely to experience respiratory symptoms, such as wheezing and phlegm, in their 20s, according to research presented at the European Respiratory Society (ERS) Congress in Vienna, Austria.

The study also found that the majority of young smokers had taken up the habit before they turned 18, and that the more cigarettes they smoked overall, the higher the risk of respiratory symptoms.

Researchers say the study highlights the risks to children and teenagers from smoking, and shows how rapidly the effects of tobacco can be seen. This is important since, in Europe, an estimated 16.7% of males and 11.2% of females aged between 15 and 24 are daily smokers.

The research was presented by Dr Linnea Hedman, associate professor of epidemiology and public health at Umeå University, Sweden.

Researchers recruited 3430 eight-year-old children in northern Sweden and asked them to fill in questionnaires annually until they turned 19 and again when they reached the age of 28.

Overall, 22% said they were daily smokers at some point during the study. Of those who said they smoked, 29% started smoking when they were 15 or under, 35% started smoking when they were 16 or 17, and 35% started at 18 or older.

The researchers took into account other factors that can affect lung health, such as a family history of asthma or growing up in a home where others smoke. They found that smoking more cigarettes overall increased the risk of respiratory symptoms by the age of 28, with one ‘packyear’ increasing the risk by around 10% compared to non-smokers. A packyear is the equivalent of smoking one pack of 20 cigarettes per day for one year.

Starting smoking under the age of 18 increased the risk of respiratory symptoms by the age of 28 by around 80% compared to non-smokers. In people who took up smoking at 18 or later, the risk was around 50% higher than non-smokers.

The most common respiratory symptoms were wheezing, phlegm and coughing.

Dr Hedman said: “In our study we found that smokers are very likely to have taken up the habit before they turned 18 and those who did start early were more likely to be suffering with breathing problems, especially wheezing and phlegm. These symptoms were also more common the more cigarettes people smoked.

“One explanation for our findings could be that children and teenagers who started smoking earlier continue to smoke for a longer time and therefore suffer with more symptoms. It could be that exposure to tobacco smoke at a young age increases the risk of respiratory symptoms because the lungs are still developing and more vulnerable to damage.

“This study shows that it does not necessarily take decades to develop respiratory symptoms from smoking; we can already see a significant association in young adulthood.”

Dr Hedman and her colleagues will continue to monitor the people taking part in the study. They are now measuring the participants’ lung function to understand how exposure to tobacco smoke influences their respiratory health in the longer term.

Professor Des Cox is a member of the ERS Tobacco Control Committee and consultant in paediatric respiratory medicine at Children's Health Ireland, Crumlin, Dublin, Ireland and was not involved in the research. He said: “Across Europe and the rest of the world, there are still a significant number of children and teenagers smoking cigarettes. We need regulations and support to help children and young people avoid or quit smoking.

“At the same time, we’re starting to see more and more children and teenagers vaping. It’s too early to know exactly what this is doing to their lungs. What we do know is that nicotine is highly addictive and the earlier you start, the longer you continue to use nicotine products.

“We want children and adults to breath clean air. That’s why the European Respiratory Society warns that all nicotine and tobacco products, including vapes and cigarettes, are highly addictive and harmful. We want the next generation to have a tobacco- and nicotine-free childhood.”

Reference:

Smoking before the age of 18 increases the risk of developing respiratory symptoms in your 20s, European Respiratory Society, Meeting:European Respiratory Society Congress 2024.