How does cannabis affect the respiratory tract

Smoking weed is on the lungs

What's in the joint

It is known that cigarettes inhale over 4,800 different substances when smoking. But which substances are actually inhaled when burning cannabis - apart from THC? A Canadian research team has got to the bottom of this question and has examined the smoke that is produced when burning cannabis with the help of standardized tests. A comparison with cigarette smoke shows that when cannabis and tobacco are burned, essentially the same pollutants are produced. The difference lies in the amount of individual substances. Cannabis smoke contains up to 20 times more ammonia and 5 times more hydrocyanic acid than smoke from tobacco. These substances damage the cilia in the airways, so that the self-cleaning of the bronchi is impaired. This also increases the length of time other carcinogenic substances remain in the lungs. In contrast, higher amounts of polycyclic hydrocarbons, formaldehyde and nitrosamines were found in tobacco smoke - all substances that are considered carcinogenic.

Blisters in the lungs

A study from Switzerland shows the consequences that pollutant uptake can have on the lungs. The doctors at Inselspital in Bern noticed that in recent years, more and more young patients have had to undergo surgery for lung collapse and emphysema. Advanced lung tissue destruction was found in these individuals. The first thing in the lungs is that they form large bubbles. When the bubbles burst, the lungs collapse because they don't have enough room to breathe because of the leaked air.

The so-called bullous emphysema does not normally occur in this pronounced form in young people who smoke cigarettes. Under the direction of Professor Ralph Schmid, a research team from Inselspital examined the phenomenon of severe lung damage as part of a two-and-a-half-year study. In it, the team comes to the conclusion that there is a connection with long-term intensive cannabis use. Because in a control group of people of the same age, most of whom smoke cigarettes regularly, no emphysema occurred.

An Australian research group comes to similar results in a comparable study. According to their calculations, bullous emphysema would occur around 20 years earlier in cannabis users than in people who only smoke tobacco.

Which of the inhaled substances in cannabis smoke causes the pronounced lung damage has not yet been clarified. In the Swiss study, however, cannabis fibers were detected that get from the unfiltered joints directly into the lungs and act there as foci of inflammation. Prof. Schmid: "The dose makes the poison: Anyone who has regularly, especially daily, consumed cannabis for years must expect severe lung damage and respiratory problems."

One joint is the equivalent of up to five cigarettes

A New Zealand research group led by Richard Beasley has investigated how badly cannabis affects the lungs. Here, cannabis users had to undergo special lung function tests and were screened with high-resolution computed tomography. Their results show that smoking weed immediately clogs the lungs - and the worse the more joints the test subjects had smoked. They come to the conclusion that one joint is about as bad for the lungs as two and a half to five cigarettes.

Increased risk of lung cancer?

In view of the findings, the question arises whether the risk of lung cancer is also increased. There are contradicting research results on this question. The aforementioned New Zealand researcher Richard Beasley calculated in a second study that the risk of developing lung cancer increases by 8 percent per year of use compared to people who do not smoke. Important influencing factors such as cigarette consumption were taken into account. If only cigarettes are smoked, however, the risk increases by only 7 percent per year of consumption. One point of criticism of the study, however, is the comparatively small sample of 79 lung cancer patients.

In a significantly larger sample of 611 patients with lung cancer, however, a US research team led by Donald Tashkin came to the opposite conclusion. Even those people who had smoked more than 20,000 joints in their lifetime were not found to be at increased risk of lung cancer.

A final statement on the relationship between lung cancer and cannabis use is therefore still pending. Or maybe this is just an academic question. Because if the joint is mixed with tobacco or cannabis users also smoke cigarettes, there is an increased risk of lung cancer anyway.

Risk of diluents

Since cannabis is illegal and insofar as it is traded on the black market, there is an additional risk that toxic extenders are added. According to reports, marijuana is stretched with sugar or quartz sand, among other things. Cases that became known for the first time in Leipzig in which marijuana was stretched with lead shavings are extremely dangerous. The marijuana stretched in this way can lead to acute lead poisoning. The following signs appear in acute lead poisoning: pale skin color, gastrointestinal complaints, severe stomach cramps ("lead colic"), slow pulse, high blood pressure. Since lead accumulates in all tissues and is not soluble in water, it is very poorly excreted without special medication. Chronic poisoning is the result. Affected people are advised to have a doctor examined if they suspect it. Medical confidentiality is observed in all cases.