A recent research presentation from a clinical ophthalmology group in UCLA has reported that “e-cigarette” smoking is associated with visual impairment in the Behavioral Risk Factor Surveillance System (BRFSS) survey (Golla et al, IOVS, 2021 (62), 3520). A US population-based study conducted a nationwide survey that involved U.S. adults ages 18+ and questioned them about health behaviors in conjunction with e-cigarette usage, given the strong association between tobacco smoking and alcohol use. While e-cigarette smoking is presented as a less harmful substitute for smoking, and a smoking cessation aid, there are concerns on e-cigarette use and their potential impact on the incidence of several healthcare conditions, including those related to eye diseases.
E-cigarettes work by applying heat to a liquid solution for inhalation, comprising of vegetable glycerin, propylene glycol, flavoring agents and sometimes, nicotine. The vapor produced by e-cigarettes inhale ultrafine particles and substances which are toxic to the lung, and potentially other tissues. Certain flavoring agents are used in e-cigarettes in many countries and some health agencies have reported known airway irritants and asthma sensitizers to cause occupational asthma. E-cigarette use has been associated with increased risk of respiratory symptoms including dyspnoea, decreased lung function and airway inflammation, a 40% increase risk of asthma and a 50% increase risk of chronic obstructive pulmonary disease (COPD), and a risk associated on chronic bronchitis.
The prevalence of current e-cigarette use varies from country to country ranging from 1.1% to 5.5% of adults and 1% to 35% of adolescents. In the current study, 1,173,646 participants were included in the survey. 6.2% of current e-cigarette smokers and 5.8% of former e-cigarette smokers stated they were visually impaired, as opposed to only 4.7% of never e-cigarette smokers. The results of the study were weighted percentages, which BRFSS used to more accurately represent the total population from the survey. The odds ratio of visual impairment in current e-cigarette smokers compared to never smokers was 1.37 (95% CI, 1.14-1.64) adjusted, and 1.36 (95% CI, 1.15-1.61) unadjusted. The odds ratio of visual impairment in former e-cigarette smokers compared to never smokers was 1.21 (95% CI, 1.09-1.35) adjusted, and 1.20 (95% CI, 1.09-1.31) unadjusted. Even though this study was used to collate survey data, the valuable report indicates that further data is required. One of the lead researchers, Dr. Abhinav Golla, MD, from the University of California, Los Angeles, commented that, “though e-cigarettes do not contain tobacco, they do share two really important similarities with traditional cigarettes. They both have nicotine and they are both shown to create oxidative stress and decrease antioxidants.”