A new study found partial nicotine in salt-based e-cigarettes was linked to acute compensatory puffing.1 Compared to smoking 5% of nicotine, e-cigarette use with 3% or 2.4% of nicotine concentration was linked to greater puffing time, puff duration, and total inhaled volume. The findings indicate a < 5% nicotine concentration has the potential to increase exposure to toxicants in the short term.
“Our study showed that taking deeper and more prolonged puffs was the most prominent adaptation among the users with moderate to high dependence in response to nicotine reduction compared with less-dependent users,” wrote investigators, led by Tarana Ferdous, MPH, PhD candidate, from Robert Stempel College of Public Health and Social Work at Florida International University in Miami. “This is important, as it will likely affect the yield of the toxic effect in a unique way that is specific to this tobacco-use method since puffing parameters have differential effects on aerosolized toxicants.”
Many young people have turned to vaping these e-cigarettes, believing it is safer than a cigarette. Although e-cigarettes do not contain cancer-causing tobacco, they can cause many adverse events—throat and mouth irritation, headache, cough, and feeling sick.2 Additionally, vaping’s long-term outcomes are not fully known.
However, e-cigarettes contain highly addictive nicotine and can be damaging to the developing brains of teens, kids, and fetuses in the womb.3 E-cigarettes have potentially harmful substances such as diacetyl, which is a chemical linked to a serious lung disease. By vaping people breathe in toxic contaminants, such as cancer-causing chemicals, nickel, tin, and lead.
With the epidemic use of e-cigarettes among the younger generation, it is crucial to address the addictiveness of these products.1 Investigators aimed to evaluate the effect of partial nicotine reduction on the puffing behaviors of gen Z and younger millennials who vape.
The team conducted a randomized crossover clinical trial of 50 e-cigarette users at the Clinical Research Lab for Tobacco Smoking at Florida International University in Miami from April 15, 2022, to October 17, 2023. Participants, aged 21 – 35 years, were included if they preferred using a salt-based, high-nicotine concentration of 5%. The sample had a mean age of 23 years, 56% were men, and 46% were low nicotine dependent.
The primary objective was the puffing topography parameters, including total session time, puffing time, total puffing number, interpuff interval, total inhaled volume, average puff volume, duration, and flow rate. These parameters were measured during each session. Plasma nicotine was also measured before and after each session.
Using a crossover design, participants completed 2 sessions of the same product (JUUL or NJOY) that varied by nicotine concentrations (either 3% [JUUL], 2.4% [NJOY], or 5% (JUUL or NJOY]) in a random order. In each session, participants had 12 hours of nicotine abstinence before vaping ≥ 60 minutes ad libitum.
Investigators found the median topography parameters of puffing time, puff duration, and total inhaled volume were significantly greater during the e-cigarette use sessions with 3% or 2.4% nicotine concentration versus 5% nicotine concentration:
- Puffing Time: 1.3 minutes (IQR, 0.3 - 9.4 minutes) vs 1.2 minutes (QR, 0.2 - 5.6 minutes); P = .02
- Puff Duration: 2.6 seconds (IQR, 0.8 - 6.9 seconds) vs 2.4 seconds (IQR, 0.4 - 6.6 seconds); P = .02
- Total Inhaled Volume: 1990.0 mL (IQR, 279.0 - 24 400.0 mL) vs 1490.0 mL (IQR, 148.0 - 14 300.0 mL); P = .05
However, the median plasma nicotine boost found in the 5% nicotine concentration condition (0.0060 mg/L [IQR, 0.0001 - 0.0249 mg/L]) was significantly greater than in the 3% or 2.4% session 0.0043 mg/L [IQR, 0.0008 - 0.0225 mg/L]) (P = .001).
“…these enhanced puffing patterns were not enough to achieve similar plasma nicotine boost levels, in which the regular nicotine potency session delivered significantly higher levels of nicotine,” investigators wrote.
Study Limitations Identified by Investigators
- Laboratory setting may have influenced vaping behavior
- Only 2 e-cigarette brands tested
- Acute model limits understanding of long-term effects of nicotine reduction
- Design did not address statistically significant vs. clinically relevant topography differences
Despite that, deeper puffing, indicating an increased average puff duration and average puff volume, was observed in participants with greater nicotine dependence (1.42 seconds [95% CI, 1.12-1.80 seconds]; P = .03) and male users (1.38 mL [95% CI, 1.09-1.75 mL]; P = .04) when nicotine concentration was < 5%.
“Although based only on an acute effect model, these findings raise the possibility that partial nicotine reduction can lead to more toxicant exposure, at least short term, due to enhanced puffing patterns,” investigators wrote. “This acute compensatory response, however, does not preclude a population benefit (ie, nicotine-naive users) due to the marketing of less addictive products.”
References
- Ferdous T, Roy S, Chowdhury S, et al. Partial Nicotine Reduction and E-Cigarette Users’ Puffing Behaviors Among Adults Aged 21 to 35 Years: A Randomized Crossover Clinical Trial. JAMA Netw Open. 2024;7(7):e2422954. doi:10.1001/jamanetworkopen.2024.22954
- What Do We Know About Cigarettes? American Cancer Society. June 23, 2022. https://www.cancer.org/cancer/risk-prevention/tobacco/e-cigarettes-vaping/what-do-we-know-about-e-cigarettes.html. Accessed July 30, 2024.
- Is Vaping Better Than Smoking? American Heart Association. January 5, 2024. https://www.heart.org/en/healthy-living/healthy-lifestyle/quit-smoking-tobacco/is-vaping-safer-than-smoking. Accessed July 30, 2024.