[Health Focus] "Young adults who use e-cigarettes for a long time show decreased lung function after one year."

A study found that young adults who use e-cigarettes for long periods of time may experience decreased lung function, including a decrease in the amount of air they can forcefully exhale in the first second after exhaling.

A research team from Florida International University, the University of Miami, and the University of Michigan announced on the 11th in the medical journal Tobacco Control that they confirmed these results by following 22 e-cigarette users aged 21 to 35 for an average of 12 months or more.

The research team said that this study shows that long-term use of e-cigarettes in young people can lead to lasting changes in lung function, and that although further research is needed, the cumulative effect of these effects may increase the risk of chronic obstructive pulmonary disease (COPD).

As e-cigarette use spreads, it becomes important to assess its long-term effects on major health problems such as COPD. The team's previous research has shown that e-cigarettes have short-term harmful effects consistent with changes in airway obstruction.

However, the research team pointed out that the chronic effects on lung function of long-term use of e-cigarettes are not yet known.

From April 2022 to December 2024, the research team conducted lung function tests on 14 men and 8 women aged 21 to 35 who mainly use e-cigarettes in the Miami area at the start and at the follow-up time one year later.

Participants had used regular cigarettes or other tobacco products five or fewer times in the past month. The lung function test was conducted without using any tobacco products for 12 hours for both tests to ensure that recent use of electronic cigarettes or tobacco did not affect the results.

In the pulmonary function test, forced expiratory volume in 1 second (FEV1), which is the amount of air that can be strongly exhaled in the first second after taking a deep breath, and forced vital capacity (FVC), which is the total amount of air that can be exhaled as quickly and strongly as possible, were measured.

FEV1 is an indicator that can decrease when the airway narrows or lung function declines, and is important in assessing the progression and risk of chronic obstructive pulmonary disease.

As a result of the test, the amount of air (FEV1) expelled in the first second after the participants started exhaling decreased by 100 ml from an average of 3.85 liters at the beginning of the study to 3.75 liters about a year later. The ratio compared to the lung function level expected for healthy people of the same age, gender, and height also decreased from 96.86% to 94.22%. Both changes were statistically significant.

On the other hand, effort vital capacity (FVC) barely changed from 4.55 liters to 4.54 liters, and the ratio of FEV1 divided by FVC did not show a statistically significant difference. This means that not all lung function test items decreased equally.

In an analysis based on the frequency of daily e-cigarette use, FEV1 tended to decrease further as the number of uses increased. Compared to users 0 to 4 times a day, it was analyzed that users 5 to 9 times a day decreased by 100 ml, users 10 to 29 times a day decreased by 190 ml, and users 30 or more times a day decreased by 240 ml.

However, after adjusting for factors that may affect the results, such as the type of electronic cigarette and past smoking experience, the observed trend of decreasing FEV1 according to frequency of use was not statistically significant.

The research team said that this study confirmed a decrease in forced expiratory volume per second (FEV1) in young e-cigarette users over a period of about a year, providing preliminary evidence that chronic use of e-cigarettes may lead to lasting changes in respiratory function.

However, this study was a preliminary study that looked at the relationship between long-term use of e-cigarettes and changes in lung function. It had a small number of participants, measured lung function only at two time points, and did not have a control group of non-users of tobacco products, so it cannot be confirmed that e-cigarettes caused a decrease in lung function.

He added that long-term follow-up studies comparing e-cigarette users and non-users of tobacco products are needed to determine how quickly FEV1 decreases over time and whether these changes lead to chronic obstructive pulmonary disease risk.

◆ Source: Tobacco Control, Wasim Maziak et al., "Prolonged effect of e-cigarette use on pulmonary function: A Pilot Study", https://tobaccocontrol.bmj.com/lookup/doi/10.1136/tc-2025-059746