Maternal vaping during pregnancy impairs offspring vascular, metabolic, and neuronal development, and the damage persists throughout the offsprings’ adult life. New research in rats published in The Journal of Physiology showed that fetal exposure to e-cigarettes caused weight gain, memory loss, behavioural changes, and advanced cellular and vascular ageing in the offspring. The harms occurred early on in development and continued throughout the offsprings’ lifetime.
Nicotine, the addictive compound in cigarettes and in vaping products, has previously been blamed as the major culprit for the poor health side effects. The researchers from West Virginia University, School of Medicine, US, found that nicotine is not the principal chemical of concern, as the long-term health effects occurred with or without nicotine.
One of the study’s authors, Mark Olfert, says, “Blood vessel impairment (impacting how a vessel relaxes or constricts) was not due to nicotine but rather the base solution (known as e-liquid) used in vaping devices. The settings used to heat the e-liquid was also an important factor, a higher power setting caused greater impairment. Thus, vaping during pregnancy with or without nicotine leads to harm in offspring. Most concerning is that this damage stayed with the offspring through adolescents and into middle-age adult life, even though the offspring never directly vaped themselves.”
Mark Olfert adds, “Finding that nicotine is not the only villain with smoking, and especially with vaping, was a pivotal moment. E-cigarettes have become increasingly popular, advertised as ‘safer’ than traditional cigarettes. Our study suggests that even if you vape without nicotine, your risk for cardiovascular disease is the same as if you are smoking a traditional cigarette.”
To carry out the study pregnant female rats were divided into four exposure groups and one control group. The pregnant rats were exposed to either no nicotine or 50mg/ml concentration of nicotine at different power settings of 5 or 30 Watts.
Male and female offspring were monitored from one month after birth, which is equivalent to a 1.5 year old human child, until 12 months after birth, which is equivalent to a 40 year old human. All offspring were assessed through behavioural tests, and memory recall and recognition tests. Cognitive impairment in offspring was greater at 30-Watt vs 5-Watt power setting. Nicotine exposure worsened brain health and function, causing neuronal damage and short-term memory loss in young and adult offspring.
The researchers found that an anti-ageing gene, called SIRT1, was reduced, which could have caused the metabolic and vascular dysfunction in the offspring. The middle-aged adult offspring also had an increase in the protein, beta amyloid, in the brain, which is known to disrupt healthy neuronal function and is a hallmark of Alzheimer’s Disease. Mark Olfert says, “The combined changes in the expression of specialised genes and proteins in the exposed offspring lead to cellular ageing and cognitive decline much earlier in life compared to offspring that did not experience e-cigarette exposure.”
The long-term health effects of vaping in humans are largely unknown as e-cigarettes have only been on the market since 2006. Mark Olfert says, “We should not assume that vaping during pregnancy is either ‘safe’ or even ‘safer’ than smoking until we understand the long-term effects to both users and those indirectly exposed, such as in utero exposure during pregnancy.”
As this study was conducted on rodents, caution is required when making direct comparisons to humans. “The health effects reported in our study are just the first step toward better understanding the effects of vaping during pregnancy on the developmental origins of health and disease. More research is needed,” says Mark Olfert.
The authors excluded flavourings from the e-liquid in their study. This was intended to assess the role of nicotine compared to the base solution alone. Thermal degradation of flavourings is known to occur during vaping which could produce harmful chemical which could each have adverse health effects. Given that flavourings can be popular among people who vape, the fact the study did not use a flavouring means it could underpredict the risk of harm. But Mark Olfert adds, “Understanding the harm from the base solution by itself provides broad insight into the relevant health risks to vaping for all users.”
Notes for editors
- Full paper title: Nicotine influence on cerebrovascular and neurocognitive function with in-utero electronic cigarette exposure. Link to paper: https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP289175.
- The Journal of Physiology publishes research in all areas of physiology and pathophysiology that illustrates new physiological principles, mechanisms or premises. http://jp.physoc.org
- The Physiological Society has been at the forefront of science for 150 years and is Europe’s largest network of physiologists. It supports physiologists by organising world-class conferences and offering grants for research and also publishes the latest developments in the field in its family of scientific journals, The Journal of Physiology, Experimental Physiology, The Journal of Precision Medicine: Health and Disease, The Journal of Nutritional Physiology and Physiological Reports. physoc.org