Smoking Marijuana: Is It Safe for Someone with Mild COPD?

Smoking Marijuana and the Lungs

Dear Dr. Mahler:

I live in Massachusetts where marijuana was legalized for recreational use this past November. What are your thoughts for smoking an occasional joint to “chill?” My primary care doctor has told me that I have mild COPD. I smoked cigarettes for about 20 years, but quit two years ago. I am currently taking Tudorza Pressair twice a day, and may use ProAir a few times a month. How safe is smoking marijuana for my lungs?

Brian from Wooster, MA

Dear Brian:

Marijuana is the second most commonly smoked substance after tobacco.

Plant used for smoking marijuana

Marijuana plant

Although the harmful effects of tobacco smoke are well known, there is less information about the health effects of smoking marijuana. As most people know, marijuana can be inhaled in many ways – a joint, vaping, and water pipes – are the most common. It is impossible to predict if you will experience any lung damage from smoking an “occasional joint.” Here is some health information for you to consider.

How can smoking marijuana damage my lungs? Smoke of any kind can cause bronchitis – inflammation and swelling of the breathing tubes. Marijuana smoke contains many of the same harmful chemicals as in tobacco smoke. We do not know if light users who smoke an amount equal to 1 – 2 joints a month over a long time may worsen your mild COPD. 

Smoking marijuana may cause a lung bullae

Arrows shows a lung bulla in the right upper lobe of the lung

There is evidence that smoking marijuana can cause large air sacs, called bullea, to develop in the lung. This is more likely to happen in younger marijuana smokers (less than 45 years of age). A bulla can cause someone to be short of breathe and may rupture or “pop.” Air leaking from a ruptured bulla can lead to a collapsed lung called a pneumothorax.

For anyone with asthma or COPD, smoking marijuana can cause a “breathing attack.”

What symptoms indicate that smoking marijuana is affecting my lungs? Like tobacco smoke, marijuana smoke can cause coughing, mucus, wheezing, shortness of breath, and swelling in the throat.

Does smoking marijuana increase my risk of lung cancer? The answer is unclear, but it may increase the risk of lung cancer as marijuana smoke contains over 450 unique chemicals including those that can cause cancer (called carcinogens).

Can marijuana increase my risk of a lung infection? Marijuana smokers can develop a lung infection from a mold called aspergillus. The mold, or fungus, lives on marijuana plants and is inhaled in smoke. 

Has marijuana been used to treat some medical problems? Yes, marijuana has been used to treat many conditions including nausea and chronic pain. Several states allow health care providers to prescribe marijuana for health reasons. However, the Food and Drug Administration (FDA) has not approved marijuana for any medical condition. The FDA has approved medications that contain tetrahydrocannabinol (THC), the active ingredient in marijuana, for treatment of pain and nausea.

In summary, smoke of any kind has the potential to damage your lungs, and is not recommended for anyone who has a lung condition. I hope that his information is helpful for you in making an informed decision.


Donald A. Mahler, M.D.



Exercise Lowers Risk of Lung Cancer by 20%

Exercise Reduces Risk of Any Cancer including Lung Cancer

Anyone who has COPD due to cigarette smoking has an increased risk for lung cancer. However, there is good news from a recent report from the National Cancer Institute.

Dr. Steven Moore, a cancer epidemiologist, analyzed 12 studies that involved 1.4 million people who reported on their physical activity levels over a period of 11 years. Dr. Moore matched these peoples’ exercise records with whether they developed 26 different types of cancer.

Woman exercising on treadmill

Woman exercising on treadmill

Overall, people who exercise more saw a 7% lower risk of developing any type of cancer than people who exercised less. But the reduced risk was especially striking for 13 types of cancers. People who were more active had on average a 20% lower risk of cancers of the esophagus, lung, kidney, stomach, endometrium and others compared with people who were less active.


The relationship between physical activity and lower cancer risk remained after adjusting for body weight (body mass index or BMI), diet, and whether or not people smoked.

Physical Activity includes Water Aerobics

Seniors doing Water Aerobics

The reason for the benefits of exercise in lowering the risk of these cancers isn’t clear. It is possible that physical activity can shift insulin and inflammation to more beneficial levels that don’t promote cancer formation.

The study was published online in JAMA Internal Medicine May 16, 2016. doi:10.1001/jamainternmed.2016.1548


Highlights from 2015 American Thoracic Society meeting in Denver

Highlights of the American Thoracic Society conference held in Denver, CO, from May 15- 20, 2015

Here are the highlights from presentations on May 19 that considered other medical conditions that can occur in those with COPD.

1. Combined pulmonary fibrosis (lung scarring) and emphysema

Dr. Sharon Rounds

Dr. Sharon Rounds

Dr. Sharon Rounds from Brown University reviewed the combination of lung scarring in the lower parts of the lung with emphysema in the upper parts. This occurs more likely in men and causes low oxygen level. Treatment is the same as for COPD.

2. Pulmonary hypertension (high blood pressure in the blood vessels of the lungs)

Dr. Mark Dransfield from the University of Alabama described the presence of high pressure in the blood vessels of the lungs. This may be due to a low oxygen level and/or damage to the lining of the blood vessels. This problem can add to shortness of breath and is diagnosed usually by an echocardiogram (ultrasound of the chest). Oxygen is the major treatment.

Dr. Mark Dransfield

Dr. Mark Dransfield

3. Obstructive sleep apnea

As part of the highlights of the conference, Dr. Patrick Stollo from the University of Pittsburgh reported that obstructive sleep apnea may co-exist with COPD. Those who have sleep apnea typically snore at night, stop breathing for at least 10 seconds many times during sleep, and are tired during the day because of poor sleep quality. This condition is diagnosed by monitoring the oxygen level during sleep or possibly by more extensive monitoring in a sleep laboratory.

4. Lung cancer

Dr. James Jett from National Jewish Healthcare in Denver commented that even if surgery for lung cancer is not possible because of severe COPD, targeted radiation therapy may be effective with minimal damage to the lung.

5. Overlap between asthma and COPD

Dr, Claus Vogelmeier of Marburg Univeristy Hospital in Germany, discussed  individuals who have features of both asthma and COPD. Treatment should be directed for asthma.

6. Assessing dyspnea (shortness of breath)

I discussed what doctors should consider when someone with COPD finds that their breathing is getting worse. One possibility is that the person with COPD is not able to inhale the medications deep into the lungs. If so, there are options including use of nebulized medications. Other considerations for worsening breathing are weight gain, being “out of shape,” having low number of red blood cells (anemia) or a heart problem. Finally, both anxiety and depression can make breathing seem more difficult. In a study performed in Lebanon, NH, individuals who had high anxiety scores reported that their breathing felt “frightening,” or “awful.”

Lung Cancer Screening Approved

Most individuals who have COPD are at increased risk for lung cancer because of cigarette smoking. On February 5, 2015, the Centers for Medicare & Medicaid Services (CMS) announced they will pay for lung cancer screening with low-dose CT scans for eligible individuals. This coverage is effective immediately. However, the details are quite specific and are summarized here. You must be:

  1. 55 to 77 years of age
  2. either current smokers or quit smoking in the previous 15 years
  3. have a 30 pack-year history of tobacco smoking (an average of one pack a day for 30 years)
  4. have a written order from a physician or qualified non-physician (nurse practitioner or physician’s assistant) that meets certain requirements
  5. have a visit for counseling and shared decision-making on the benefits and risks of lung cancer screening

There are additional requirements for radiologists interpreting the CT scans and for places (hospitals and imaging centers)  where the CT scan is done.

If you qualify and are interested in have the screening CT scan done, you should ask your doctor whether the local hospital or medical center is doing such testing. It may take a while for some health care facilities to get ready for such screening.

Of note: “This is the first time that Medicare has covered lung cancer screening. This is an important new Medicare preventive benefit, since lung cancer is the third most common cancer and the leading cause of cancer death in the United States,” said Patrick Conway, MD, chief medical officer and deputy administrator for innovation and quality at the CMS.