Young and old, male and female: the effects of nicotine vaping
In the past couple of years, you may have heard that the rates of smoking in Canada and the rest of the world are declining. Some people attribute this decline to tobacco control measures such as pictorial warnings on cigarette packaging, as well as the aggressive anti-smoking campaigns of the 2000s—if you were in elementary school at the time, you may recall seeing some of them in health class. And while the decrease in the rates of tobacco smoking is a major public health victory, the full picture is not quite as promising. The use of e-cigarettes, also referred to as vaping, is on the rise, especially among the younger crowd; in fact, approximately 30% of Canadian youth aged 15-19 have reported vaping at some point in their lives. This is especially troubling given the fact that adolescents are particularly susceptible to the harmful effects of nicotine, which is the mind-altering substance that makes cigarettes and e-cigarettes so addictive. Some research suggests that females are also more vulnerable to the effects of nicotine, with lower rates of quitting smoking and higher risks of negative health effects related to tobacco smoke.
The rising popularity and potentially harmful effects of vaping on vulnerable groups are a big reason why neuroscientist Dr. Jude Frie and his colleagues at the Khokhar Lab became interested in studying nicotine vaping in the first place. As one of the first labs to utilize commercially available e-cigarettes in their research, they built the OpenVape system, which is a minimally invasive method for exposing rodents to nicotine vapour. Their recent study examined the rewarding effects of nicotine as well as nicotine withdrawal in the context of vaping. They also looked at how much nicotine makes it into the bloodstream, and subsequently the brain, of an e-cigarette user. Importantly, they conducted their experiments on four different groups of rodents: adult males and females, and adolescent males and females. Each group was exposed to the same amount of nicotine vapour, which made it possible to see how age and sex impact nicotine’s effects.
So, what did they observe? They found that nicotine was more rewarding to adult females, but not adolescent females or males of any age, and that nicotine withdrawal was seen in adult and adolescent males, but not females of any age. This is quite intriguing, especially given that the nicotine levels in the bloodstream and brain were found to be much higher in females compared to males of both age groups. In other words, although adult females find nicotine more rewarding than other groups and have higher concentrations of it in their body after vaping, it is the males that are more affected by nicotine withdrawal. Together, these results suggest that sex and age make a big difference in how our bodies are affected by vaping. Although more research is needed to further validate these findings in humans, the potential implications are broad. For example, regulations for maximal nicotine concentration in vaping products may need to become sex- and age-specific.
The necessity of nicotine vaping research is becoming increasingly clear; however, scientists face significant barriers in studying it in the lab. One such barrier is the cost of commercially available vape exposure systems for rodents. Excitingly, the design of the OpenVape system mentioned in this article is open source, which means that it is free and publicly available for anyone to build themselves. When asked why this was important to him, lead researcher Jude says, “We wanted to make it so other people can use this model, and not just the most well-funded labs… We need lots of research on this now, so let’s make it as cheap as possible so anyone can build them”. While commercially available vape exposure systems for research do exist, they can be very expensive, with some costing tens of thousands of dollars. This makes their use inaccessible to labs that are not funded very well, which often includes smaller and newer labs. Jude’s design, on the other hand, only costs about $230, allowing for nicotine research to be accessible to all labs at a time when vaping is at a peak.
Original research article: Frie, J. A. et al. Factors influencing JUUL e-cigarette nicotine vapour-induced reward, withdrawal, pharmacokinetics and brain connectivity in rats: sex matters. Neuropsychopharmacol. 49, 782–795 (2024).
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