E-Cigarette Impact on Reproductive Health

The research and development team at Fertilys has just published a review article on the effects of vaping on reproductive health.  

Vaping has increased in popularity over the past decade

Over the past decade, there has been an increasing trend in the prevalence of vaping in our population. Initially, e-cigarettes were marketed to conventional cigarette smokers as being a “safe alternative” and could be used as an aid to help quit smoking. Since then, these devices have become very popular amongst young adults. Indeed, 85% of adults from 18-29 years tried vaping in 2018 and its consumption is directly correlated with advertisement exposure [1]. Moreover, 40% of young e-cigarette users had never smoked conventional cigarettes before, suggesting that these devices might act as an entry point to conventional smoking [2]. Many young adults vaping regularly consider the usage of these devices fashionable and are not aware of their overall health risks. This stemmed from the common belief that e-cigarette utilization is less harmful than conventional cigarette smoking. Nevertheless, e-cigarettes are composed of various toxins, exposing users to substances that are not without any impact on their general health [3].

What toxins are found in E-cigarettes?

It has been shown that more than 80 different compounds can be found in the liquid and the aerosol of e-cigarettes. Some of the compounds found in e-cigarettes include:  

– Glycols – the major component of e-cigarette liquid, once heated, forms harmful constituents in the inhaled vapor [3,4].

– Nicotine – depending on the manufacturing company, one inhale from an e-cigarette device can contain 0-35 mg of nicotine [3,5]. In most cases, the detected levels of nicotine were not in accordance with the concentration disclosed by the manufacturer and were even detected in “Nicotine-Free Products” [3,6].

– Particles – different sizes of particles are generated by e-cigarettes and once inhaled will enter the respiratory system and can be deposited within the lungs [4,5].

– Metals – many metals have been consistently detected in the vapor generated by e-cigarettes including lead, chromium, tin, silver, nickel, cadmium, aluminum, and mercury [3].

– Tobacco-specific nitrosamines – formed from processing tobacco or the addition of tobacco flavoring in e-cigarettes and are considered highly toxic [7].

– Carbonyls – sugars found in the flavoring of e-cigarettes generate butyraldehyde and aldehydes once heated. These substances are known to be highly irritating and toxic [3,8].

The impact of vaping on reproduction

Studying the direct impact of vaping on reproduction is a difficult task. First, e-cigarettes, compared to cigarettes, have not been around for centuries and the long-term effects of vaping are yet to be discovered. Moreover, there are hundreds of types of e-cigarettes available on the market all varying in the specification, substances contained, and concentration of those substances making it very hard to study. Many compounds found in e-cigarettes are similar to those found in conventional cigarettes. Therefore, much of what we know about the compounds found in e-cigarettes has been through studies of conventional cigarettes.

In males, a study in humans showed that semen exposed to e-cigarette components significantly decreased sperm motility [9]. Other studies in animal models concluded that exposure to e-cigarettes directly affected sperm quality. Vaping was shown to lower sperm viability, increase the presence of sperm with abnormal morphology, and also increase DNA damage in sperm cells [10,11,12]

In females, a decreased percentage of normal follicles was described in the ovaries of female rats exposed to e-cigarette fluid. A reduction in hormones important in reproduction was also observed [13]. E-cigarette exposure also affected on time of implantation and pregnancy outcomes in these animal models [14].

What is the takeaway? 

Overall, given the numerous potential adverse effects of e-cigarettes described in animal models, one can admit that vaping is far from a safe alternative to conventional cigarette smoking. The evidence of the impact of utilization of these devices is alarming, and people trying to conceive should be aware of their potential impact on their reproductive health.

References

1- (https://www.statista.com/statistics/882611/vaping-and-electronic-cigarette-use-us-by-age) Ali, F.R.M.; Dave, D.M.; Colman, G.J.; Wang, X.; Saffer, H.; Marynak, K.L.; Dench, D.; Grossman, M. Association of e-cigarette advertising with e-cigarette and cigarette use among US adults. Addiction 2021, 116, 1212–1223

2- Sapru, S.; Vardhan, M.; Li, Q.; Guo, Y.; Li, X.; Saxena, D. E-cigarettes use in the United States: Reasons for use, perceptions, and effects on health. BMC Public Health 2020, 20, 1518.

3- Pisinger, C.; Døssing, M. A systematic review of health effects of electronic cigarettes. Prev. Med. 2014, 69, 248–260.

4- Thirión-Romero, I.; Pérez-Padilla, R.; Zabert, G.; Barrientos-Gutiérrez, I. Respiratory impacy of electronic cigarettes and “low-risk” tobacco. Rev. Investig. Clin. 2019, 71, 17–27

5- Hutzler, C.; Paschke, M.; Kruschinski, S.; Henkler, F.; Hahn, J.; Luch, A. Chemical hazards present in liquids and vapors of electronic cigarettes. Arch. Toxicol. 2014, 88, 1295–1308.

6- Bertholon, J.F.; Becquemin, M.H.; Annesi-Maesano, I.; Dautzenberg, B. Electronic cigarettes: A short review. Respiration 2013, 86, 433–438.

7- Kim, H.-J.; Shin, H.-S. Determination of tobacco-specific nitrosamines in replacement liquids of electronic cigarettes by liquid chromatography–tandem mass spectrometry. J. Chromatogr. A 2013, 1291, 48–55.

8- Kubica, P.; Wasik, A.; Kot-Wasik, A.; Namiesnik, J. An evaluation of sucrose as a possible contaminant in e-liquids for electronic cigarettes by hydrophilic interaction liquid chromatography–tandem mass spectrometry. Anal. Bioanal. Chem. 2014, 406, 3013–3018.

9- O’Neill, H.; Nutakor, A.; Magnus, E.; Bracey, E.; Williamson, E.; Harper, J. Effect of Electronic-Cigarette Flavourings on (I) Human Sperm Motility, Chromatin Integrity in Vitro and (II) Mice Testicular Function in Vivo. 2017. Available online: http://srf-reproduction.org/wp-content/uploads/2017/01/Fertility-2017-Final-Programme-and-Abstracts.pdf (accessed on 20 January 2023)

10- El Golli, N.; Rahali, D.; Jrad-Lamine, A.; Dallagi, Y.; Jallouli, M.; Bdiri, Y.; Ba, N.; Lebret, M.; Rosa, J.; El May, M.; et al. Impact of electronic-cigarette refill liquid on rat testis. Toxicol. Mech. Methods 2016, 26, 417–424. 

11- Rahali, D.; Jrad-Lamine, A.; Dallagi, Y.; Bdiri, Y.; Ba, N.; El May, M.; El Fazaa, S.; El Golli, N. Semen Parameter Alteration, Histological Changes and Role of Oxidative Stress in Adult Rat Epididymis on Exposure to Electronic Cigarette Refill Liquid. Chin. J. Physiol. 2018, 61, 75–84. 

12- Vivarelli, F.; Canistro, D.; Cirillo, S.; Cardenia, V.; Rodriguez-Estrada, M.T.; Paolini, M. Impairment of testicular function in electronic cigarette (e-cig, e-cigs) exposed rats under low-voltage and nicotine-freeconditions. Life Sci. 2019, 228, 53–65. 

13- Chen, T.; Wu, M.; Dong, Y.; Kong, B.; Cai, Y.; Hei, C.; Wu, K.; Zhao, C.; Chang, Q. Effect of e-cigarette refill liquid on follicular development and estrogen secretion in rats. Tob. Induc. Dis. 2022, 20, 36. 

14- Wetendorf, M.; Randall, L.T.; Lemma, M.T.; Hurr, S.H.; Pawlak, J.B.; Tarran, R.; Doerschuk, C.M.; Caron, K.M. E-Cigarette Exposure Delays Implantation and Causes Reduced Weight Gain in Female Offspring Exposed In Utero. J. Endocr. Soc. 2019, 3, 1907–1916.