Although the prevalence of cigarette smoking has significantly declined from nearly 21% of the U.S. adult population identifying as smokers in 2005 to only 14% today, an estimated 34.1 million adults still currently smoke cigarettes. In addition, many have transitioned to the use of electronic cigarettes in hopes of reducing cardiometabolic risks. However, the cardiovascular toxicity of electronic cigarettes is not well understood and comprehensive population data assessing their adverse effects remains sparse.
Researchers continue to investigate the repercussions of both cigarette and e-cigarette use, including the specific cardiovascular disease biomarkers that can act as predictive factors for CVD events. Inflammation and oxidative stress have been identified as key contributors of smoking-induced cardiovascular disease prompting scientists to evaluate these measures in current smokers. Findings recently published in Circulation reveal that similar levels of inflammation and oxidative stress biomarkers can be observed in patients who use both electronic cigarettes and cigarettes and those who exclusively smoke cigarettes.
CVD Biomarkers Tied to Smoking
Led by Andrew C. Stoked, PhD, from the American Heart Association Tobacco Regulation and Addiction Center in Dallas, a team of researchers examined the relationship between cigarette and e-cigarette use behaviors with biomarkers of inflammation and oxidative stress among adults aged 18 years and older from the Population Assessment of Tobacco and Health Study— a nationally representative longitudinal cohort in the United States. The study’s authors examined data from a total of 7,130 participants.
Study participants were classified based on cigarette/e-cigarette use in the previous 30 days as nonusers, exclusive e-cigarette users, exclusive cigarette users, and dual users. To understand the effects of these products on cardiovascular health, the team evaluated biomarkers for inflammation which included high-sensitivity C-reactive protein, interleukin-6, fibrinogen, soluble intercellular adhesion molecule – as well as oxidative stress measured by urinary 8-isoprostane levels and then adjusted for covariates.
Similar Levels of Inflammation, Oxidative Stress
Of the study population, 58.6% were non-users, 1.9% were exclusive e-cigarette users, 29.6% were exclusive cigarette users, and 9.9% were dual users. The researchers reported similar inflammatory and oxidative stress profiles for both nonusers and exclusive cigarette users in the multivariable models with no observed differences in biomarker concentrations between study participants. Not surprisingly, exclusive cigarette smokers and dual users had higher levels across all biomarkers compared with non-smokers. Comparable levels of all five inflammatory and oxidative biomarkers were observed for dual use and exclusive cigarette smoking.
Interestingly, exclusive e-cigarette users exhibited significantly lower levels of almost all inflammatory and oxidative stress measures – aside from high-sensitivity C-reactive protein – compared with exclusive cigarette smokers. However, data concerning e-cigarettes remains in its infancy and broadly applicable conclusions cannot be drawn regarding their safety profiles, especially in long-term users.
According to the authors, the latest findings are consistent with recent population studies of toxicant exposure and inflammatory biomarker levels in users of e-cigarettes and cigarettes and highlight the importance of completely replacing cigarette smoking with e-cigarettes or quitting the use of both products to derive potential and optimal health benefits. However, the body of literature evaluating the cardiovascular effects of e-cigarette use remains limited and further research is needed to determine the full spectrum of health implications of such products.