Smoking is on the decline, and that's a good thing. The evidence is clear that smoking kills. But what about tobacco? A few years ago groups like the U.S. Centers for Disease Control began to suggest nicotine was as harmful as smoking; meaning it was not the smoke at all. There was no evidence of that, it was only epidemiological correlation.

A new analysis of of more than 7,100 U.S. adults ages 18 and older, researchers studied the association of cigarette smoking and e-cigarette use with inflammation and oxidative stress as biomarkers. Inflammation and oxidative stress are key contributors to smoking-induced cardiovascular disease and their biomarkers have been shown to be predictors of cardiovascular events, including heart attack and heart failure.

The data from the Population Assessment of Tobacco and Health (PATH) Study Wave 1, from 2013 to 2014 and included the collection of blood and urine samples, found that participants who vaped exclusively showed a similar inflammatory and oxidative stress profile as people who did not smoke cigarettes or use e-cigarettes.

Five biomarkers of inflammation and oxidative stress were analyzed. Participants were slotted into four categories based on the use of traditional cigarettes and e-cigarettes within a 30-day period: non-use of cigarettes and e-cigarettes; exclusive vaping; exclusive cigarette smoking; and dual use of cigarettes and e-cigarettes. To test the robustness of initial results, the scientists repeated the analyses in subgroups of respondents, including those with no past 30-day use of any other tobacco products.

Of the study participants, more than half (58.6%) did not use cigarettes or e-cigarettes; nearly 2% vaped exclusively; about 30% smoked cigarettes exclusively; and about 10% used e-cigarettes and traditional cigarettes.

Participants who smoked exclusively and those who used cigarettes and e-cigarettes had higher levels across all biomarkers assessed compared to participants who did not use cigarettes or e-cigarettes. Which makes sense. Smoking is the common factor. But compared to participants who smoked exclusively, those who vaped exclusively had significantly lower levels of almost all inflammatory and oxidative stress biomarkers. Again, those who also smoked had levels of all inflammatory and oxidative stress biomarkers comparable to those who smoked exclusively.

What does it tell us? That if e-cigarettes are truly used for smoking cessation and harm reduction, they are working. If smokers just continue to do so and also use vaping devices, they face the same peril as if they smoked.

Researchers also conducted extensive analyses to test the results against the influence of related behaviors such as the use of other tobacco products and marijuana, and secondhand smoke exposure. The results remained consistent across the additional analyses.