E-Cigarettes Raise Respiratory Risk for Current, Former Users

Andrew C. Stokes, PhD

People who use electronic cigarettes face an increased risk of respiratory disease, regardless of whether they also smoke traditional cigarettes, according to a new study.

The research adds important new data about the health effects of the relatively new device.

E-cigarettes first came on the market in the US in 2007. While the devices have been shown to reduce a user’s exposure to toxic substances when used in place of traditional cigarettes, an increasing body of evidence has suggested that e-cigarettes come with significant health risks of their own. Among the problems with e-cigarettes is the fact that many contain volatile organic compounds, heavy metals, and ultrafine particles that are believed to have negative impacts on the lungs, airways, and immune system.

Corresponding author Andrew C. Stokes, PhD, of the Boston University School of Health, and colleagues, sought to figure out what effect, if any, e-cigarette usage had on respiratory conditions such as chronic obstructive pulmonary disease (COPD), emphysema, chronic bronchitis, and asthma.

To answer their question, the investigators used data from the Population Assessment of Tobacco and Health (PATH) study, a nationally representative study of adults in the United States. The study was conducted in 4 “waves” between 2013 and 2018. All subjects included in the study had no prevalent respiratory conditions at the study’s baseline.

All told, the investigators identified 21,618 subjects, of whom 11,017 were men and 12,969 were non-Hispanic and white. Most of the subjects (14,213) said they had never used e-cigarettes. Another 5076 subjects said they had previously used e-cigarettes but had given up the habit. Only 2329 were current e-cigarette users at the start of the study.

After adjusting for the use of traditional cigarettes and other related products , the investigators found patients who had previously or currently used e-cigarettes had significantly higher risks of respiratory disease: former users had an incident risk ratio (IRR) of 1.28, and current users had an IRR of 1.31 (all ratios had confidence intervals of 95%). Even among patients who self-reported being in “good health,” the IRR for former and current e-cigarette users was 1.21 and 1.43, respectively.

When broken down by specific conditions, the authors found current e-cigarette users were at the greatest risk of emphysema (IRR, 1.69) and COPD (IRR, 1.57), followed by chronic bronchitis (IRR, 1.33) and asthma (IRR, 1.31).

Stokes and colleagues wrote that it’s logical that the risk of respiratory conditions would vary from disease to disease, given the different pathologies of the various conditions. For instance, they noted that asthma is typically diagnosed in childhood.

“In contrast, COPD typically develops in mid- to later life, characterized physiologically by incompletely reversible airflow limitation by a progressive decline in lung function,” they said.

The strengths of the study, according to the investigators, were the nationally representative sample, and the careful adjustment for cigarette smoking, thereby better isolating the precise risk added by e-cigarette use. However, they said there are also a number of limitations, such as the reliance on self-reported tobacco-usage and diagnostic data, and the relatively short follow-up period.

Nonetheless, Stokes and colleagues said their data made a compelling case that e-cigarettes, like traditional cigarettes, create a serious public health burden.

“These findings add important evidence on the risk profile of novel tobacco products with respect to respiratory outcomes,” they concluded.

The study, “Association of Electronic Cigarette Use With Incident Respiratory Conditions Among US Adults From 2013 to 2018,” was published online in JAMA Network Open.