Long-Term Health Affects of Smoking Marijuana

Man smoking a joint
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We’ve come a long way from the days when smoking marijuana was strictly a hush-hush activity. From increasing acceptance of recreational products made from pot to the use of medical marijuana to treat symptoms such as pain and nausea from chemotherapy, more and more people are being open about the role marijuana plays in their lives.

But although there's less secrecy around marijuana use, it doesn’t necessarily mean it’s safe—at least not for folks who smoke pot for fun. Scientists don’t how long-term pot puffing affects the body, but there are studies that suggest it can cause several health problems over time. For instance, preliminary animal and human studies suggest smoking marijuana can put a damper on the immune system. Here are three other health problems that may be linked to using pot.

Breathing Problems

Although marijuana and tobacco are two entirely different substances, smoking either has similar effects on the lungs. These can be more severe for pot smokers because they tend to inhale more deeply. What's more, in order to bring about a high, they tend to hold the smoke in their lungs for as long as possible. This increases the amount of smoke the lungs are exposed to, putting them at even greater risk of certain respiratory problems than tobacco smokers.

For example, they may have increased production of phlegm leading to frequent coughing, and they may be especially prone to obstructed airways. Pot smokers also are at greater risk of chest colds and lung infections. When researchers in California analyzed the health records of 450 people who smoked marijuana (but not tobacco) daily, they found the marijuana smokers took more sick days off from work and had more doctor visits than did a similar group of subjects who did not smoke either tobacco or pot.

Lung Cancer

While coughing and colds are at the most annoying and inconvenient side effects of smoking marijuana, an increased risk of lung cancer is a life-threatening one. Marijuana smoke contains some of the same cancer-causing compounds as tobacco—sometimes in higher concentrations. Given the way pot smokers hold in smoke after inhaling it, it’s easy to see why, puff for puff, smoking marijuana may increase the risk of cancer more than smoking tobacco does. Studies show that someone who smokes five joints per day may be taking in as many cancer-causing chemicals as someone who smokes a full pack of cigarettes every day.

The important word here is “may.” It's a challenge for researchers to figure out whether cannabis alone causes cancer because many people who smoke pot also smoke cigarettes and use other drugs. Tobacco smoke and marijuana smoke may work together to change the tissues lining the respiratory tract.

Testicular Cancer

Smoking marijuana may be particularly dangerous for men in the long term. A number of studies suggest a link between an increased risk of testicular cancer, the most common cancer among males under 45. In one such study, published in 2012, men who smoked marijuana were two times as likely to develop testicular cancer as were those who didn't use pot. A 2015 study in the peer-reviewed journal BMC Cancer concluded that using cannabis once a week or for more than ten years was associated with an increased risk of testicular cancer (particularly testicular germ cell tumors, or TGCTs).

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Article Sources

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  • Gurney, et. al. "Cannabis Exposure and Risk of Testicular Cancer: A Systematic Review and Meta-Analysis." BMC Cancer 2015, 15:897.
  • National Institute on Drug Abuse. "Marijuana: Facts Parents Need to Know." Aug 2007.
  • Tetrault, J.M., et al. "Effects of Marijuana Smoking on Pulmonary Function and Respiratory Complications: A Systematic Review." Archives of Intern Medicine. Feb 2007.