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What makes vaping harmful?

STUDIES are being carried out to investigate the mechanisms by which vaping is bad for health, but researchers already have some ideas.

Vaping involves inhaling a vapourised liquid known as vape juice or e-liquid, which may consist of many different types of ingredients mixed in a lipid (oily) base.

These ingredients usually include flavourings, nicotine and other additives.

Outside of Malaysia, it is also common to add marijuana extracts such as THC and CBD.

Johns Hopkins University (JHU) researchers also found caffeine in the vape juice concoction they tested, which they suspect could be giving an undisclosed “extra kick” and wondered if the added addictive stimulant was an intentional ingredient.

Other compounds found by the JHU team were flavourings associated with respiratory problems, pesticides and industrial chemicals.

Although some of the ingredients used in vaping liquid may be safe such as Vitamin E and caffeine (in the correct doses), scientists know much less about the safety of a vapourised and inhaled form of these compounds.

Not to mention, the heating, vapourising, inhalation processes, interaction in the body and exhaling processes that may result in secondary chemical interactions between the thousands of chemical concoctions, resulting in more unknown compounds.

While scientists investigate the impacts of these chemicals, we do know that there are thousands of cases of hospitalisations due to severe respiratory issues linked to e-cigarettes and vapes, with a considerable number being lethal cases.

These are known as e-cigarette or vaping product use-associated lung injury (EVALI).

Given the developing field, findings and acronyms may change.

The human respiratory system has a great defence mechanism to guard itself against foreign bodies but particles of less than three to five microns in diameter can penetrate deep into the lungs.

Associate director at the Johns Hopkins Cardiothoracic Residency Programme, Dr Broderick, opined that “some of the vapourised elements of the oil are getting deep down into the lungs and causing an inflammatory response”.

A study by researchers from Jean Monnet University in France and a science and engineering research company with a focus area in vaping, Ingescience, indicate that the aerosol particle size (in their study) can range between 1.1 to 2.4 microns, depending on the power (wattage) and atomiser technology used.

Particle size for cigarettes can be many times smaller and could mean a deeper penetration into the lungs and therefore increased effectiveness in nicotine (and other chemicals) uptake, but smaller particles could also mean lesser deposition in the lungs compared with vape liquids.

A research paper by Ranpara et.al. in 2021 mentioned that aerosol sizes of less than one micron are highly likely to be inhaled and then exhaled.

In turn, this could mean a higher deposition risk compared with cigarette smoke.

The researchers also investigated the varying particle size distribution of different types of base oils (Vitamin E acetate [VEA], Vitamin E oil, coconut oil, and medium-chain triglycerides) and simulated respiratory depositions.

Vitamin E acetate and Vitamin E oil have the largest particle size and were found to be statistically different to the rest.

Vitamin E acetate has been identified as one of the major causal links to EVALI, and findings by Ranpara et.al. add further credence to this.

The researchers concluded that “these observed particle deposition patterns were consistent with previous inhalation toxicological studies and with the characterisation of bronchoalveolar lavage fluid of EVALI cases, which support the pulmonary region of the lung as the site of injury”.

Researchers from the Bhabha Atomic Research Centre in Mumbai, India found that exhaled cigarette smoke shows growth in particle size, while researchers Conor McGrath et.al. postulated mechanisms to explain the deposition pattern through processes such as coagulation, hygroscopic growth, condensation and evaporation, changes in composition, or changes in inhalation behaviour.

A research paper by Sosnowski and Kramek-Romanowska (2016) found that their tested e-cigarettes had higher aerodynamic resistance (roughly three times more) than cigarette smoke.

Therefore, it would appear that for both cigarette and vaping, exhalation has a higher chance of deposition in the lungs. Still, vape could be worse due to the combination of higher aerodynamic resistance and larger particle size of vape particles may confer higher deposition risk in the lungs.

The difference in chemical properties between vape liquid and cigarette smoke may also contribute to the difference in deposition mechanisms and characteristics.

Additionally, styles of vaping which tend to prefer larger exhaled “cloud” formation and increased lung residence time could be a magnifying factor to deposition.

Therefore, EMIR Research hypothesises that vaping may carry a higher risk of acute lung complications in the near term compared to smoking (even if shorter-term risks such as nicotine uptake may be lower) due to higher deposition risk.

Indeed, there have been many reports that support this hypothesis.

E-cigarettes and vapes have been widely associated with pneumonia (acute respiratory viral or bacterial infection of the lungs) and a specific variation called lipoid pneumonia where aerosolised droplets of lipid (oil) are deposited in the lungs.

It has been found that the immune system can be compromised with the immune cells (such as macrophages) being lipid-laden, which raises the chance of developing lipoid pneumonia.

Advanced cases may require oxygen support and ventilators, and can even be fatal.

Researchers from the University of Florida College of Medicine proposed in a 2021 paper a potential relationship between frequent vaping to increased vulnerability to viral and bacterial infection through “cytotoxic effect on lung epithelial and immune cells, and the possibility for increased the virulence possibly through biofilm formation, invasiveness, and resistance to antimicrobial peptides, leading to necrotising pneumonia and persistent bacteremia”.

Some cases point to the mounting linkage between EVALI and infections, such as mycoplasma pneumonia and necrotising pneumonia among teenagers, with cases indicating only a short-term duration of daily vaping for around two years before disease presentation. Cases also tend to involve teenagers and young adults, pointing to vaping interests among younger age groups.

These are examples pointing to the younger generation getting seriously sick faster.

To top it off, just like cigarettes, e-cigarettes and vapes have also been associated with lower fertility function.

ONE Fertility Kitchener Waterloo – a fertility and in-vitro fertilisation clinic – pointed to lowering reduced sperm quality, count and motility (ability to move) in males, and delayed egg production, fertilisation, and embryo implantation problems for women.

They also pointed to adverse effects on fetal development and stunted growth in infants and children.

This is not surprising as both vapes and cigarettes share some common ingredients such as nicotine and other compounds associated with reduced sperm health.

There are also reports that the flavouring concoction in the vape juice affects cells in the testicles and reduces sperm motility.

And these are just some of the known chemicals.

What about the mostly unidentified 2,000 chemicals found in e-cigarette and vaping liquid, as reported in a 2021 study (2021) by researchers from the JHU?


Specific recommendations have been discussed in another article by EMIR Research titled “Treat Vape Like Cigarettes”, but it is clear that shifting from smoking to vaping is far from a healthy choice.

Though longer-term impacts are less known, the vaping liquid contains nicotine and other common toxins found in cigarettes.

Mounting evidence linking acute respiratory diseases with vaping, many other health issues such as infertility and related health conditions involving the cardiovascular system, the various unknowns and insufficient longer-term data and questionable independence of studies put into question the notion of a “safer” option of vaping compared with cigarettes, even in the near term.

With increasing cases of non-communicable diseases, an ageing population, and the brain drain phenomenon, poor regulations and enforcement surrounding vapes and e-cigarettes in Malaysia could be paving the way for a health epidemic involving the youth and reducing their reproductive potential, ultimately jeopardising the health of Malaysia’s future.

Dr Rais Hussin and Ameen Kamal are part of the research team of EMIR Research, an independent think tank focused on strategic policy recommendations based on rigorous research. 

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