Steven Wright, MD, FAAFP Julius Metts, MD, FAAFP Private practice, Littleton, Colo (Dr. Wright); California Substance Abuse and Treatment Center, Department of Corrections and Rehabilitation, Corcoran (Dr. Metts) sleighwright@gmail.com
The authors reported no potential conflict of interest relevant to this article.
Elevated rates of MI.Chronic effects may include oral health problems,16 gynecomastia, and changes in sexual function.17 Elevated rates of myocardial infarction, cardiomyopathy, limb arteritis, and stroke have been observed.18 Synthetic cannabinoids have been associated with heart attacks and acute renal injury in youth;19,20 however, plant-based marijuana does not affect the kidneys. In addition, high doses of plant-based marijuana can result in cannabinoid hyperemesis syndrome, characterized by cyclic vomiting and compulsive bathing that resolves with cessation of the drug.21
Cannabis users have a lower body mass index, better lipid parameters, and are less likely to have diabetes than their non-using counterparts.No major pulmonary effects.Interestingly, cannabis does not appear to have major negative pulmonary effects. Acutely, smoking marijuana causes bronchodilation.22 Chronic, low-level use over 20 years is associated with an increase in forced expiratory volume in one second (FEV1), but this upward trend diminishes and may reverse in high-level users.23 Although higher lung volumes are observed, cannabis does not appear to contribute to the development of chronic obstructive pulmonary disease, but can cause chronic bronchitis that resolves with smoking cessation.22 Chronic use has also been tied to airway infection. Lastly, fungal growth has been found on marijuana plants, which is concerning because of the potential to expose people to Aspergillus.22,24
Cannabis and cancer? The jury is out. Cannabis contains at least 33 carcinogens25 and may be contaminated with pesticides,26 but research about its relationship with cancer is incomplete. Although smoking results in histopathologic changes of the bronchial mucosa, evidence of lung cancer is mixed.22,25,27 Some studies have suggested associations with cancers of the brain, testis, prostate, and cervix,25,27 as well as certain rare cancers in children due to parental exposure.25,27
There are conflicting data about associations with head and neck squamous cell carcinoma,25,27,28 bladder cancer,25,29 and non-Hodgkin’s lymphoma.25,30 Some studies suggest marijuana offers protection against certain types of cancer. In fact, it appears that some cannabinoids found in marijuana, such as cannabidiol (CBD), may be antineoplastic.31 The potential oncogenic effects of edible and topical cannabinoid products have not been investigated.