The Puzzle of Marijuana Use and Forced Vital Capacity

The Puzzle of Marijuana Use and Forced Vital Capacity




$25.00 USD

Provided by the American Thoracic Society
Release Date: May 01, 2024

Program Description

In study after study, marijuana use has been found to be associated with increased forced vital capacity (FVC). This is puzzling, because marijuana is commonly consumed by inhalation of its smoke, and smoke exposure of any kind is not generally considered a cause of increased FVC. Although this observation was first made decades ago, a satisfactory explanation remains elusive. In this review the authors survey the evidence supporting the relationship between marijuana use and increased FVC, discuss potential threats to validity when inferring causation, and, presupposing a possible causal relationship, pose two key questions.

First, what are possible physiologic or pathophysiologic mechanisms by which marijuana use might increase FVC? Second, why might this effect be consistently observed with marijuana use but not with tobacco use? Explanations for the first question include lung and chest growth and remodeling from strenuous marijuana smoke inhalation and reductions in lung elastic recoil from marijuana smoke exposure.

Explanations for the second include differences between marijuana and tobacco in smoke composition and patterns of consumption, such as smoking topography. Finally, the possibility that smoke, whether from marijuana or tobacco, might have nonmonotonic effects on FVC depending on the degree of exposure is explored. In synthesizing a curated breadth of epidemiologic and physiologic science, the authors leverage a perplexing observation to generate potential insights and avenues for further research into the biological effects of smoke, from marijuana or otherwise, on the respiratory system.

Target Audience

Pulmonologists, critical care specialists, translational researchers, and clinicians

Learning Objectives

At the conclusion of this activity, learners should be able to:

  • Characterize the relationship between marijuana use and forced vital capacity
  • Identify mechanisms by which marijuana use affects forced vital capacity
  • Compare and contrast the effects of marijuana use and tobacco use on respiratory physiology

Course summary

Available Credit:
1.00 Participation
1.00 AMA PRA Category 1 Credit

Credit Expires: May 01, 2026

Format: Journal

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The American Thoracic Society is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

Credit Type Credit/Points Credit Designation Statement
AMA PRA Category 1 Credit™ 1.00 The American Thoracic Society designates this Journal for a maximum of 1.00 AMA PRA Category 1 Credit(s)™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.


Article Authorship Disclosures (as submitted to the ATS prior to article publication date)

Nirav R. Bhakta, M.D., Ph.D. (University of California, San Francisco, San Francisco, CA, USA) served as Vice-Chair for the American Thoracic Society Pulmonary Function Testing Committee. 

Richard J. Wang, M.D. M.A.S. (University of California, San Francisco, San Francisco, CA, USA) received research support from the National Heart Blood and Lung Institute and the State of California Department of Cannabis Control.

Off-Label Usage Disclosure


Disclosures of AnnalsATS CME Planners

The Annals of the American Thoracic Society (AnnalsATS) original research, commentaries, reviews, and educational content of interest to clinicians and clinical investigators in pediatric and adult pulmonary and sleep medicine and medical critical care. The scope of the journal encompasses content that is applicable to clinical practice, the formative and continuing education of clinical specialists, and the advancement of public health.

The publication of articles that meet these goals by itself is only one step in a multi-step process for the translation of evidence-based improvements in are to clinical practice. Testing for CME credit is designed to function as a next step in the process. This is accomplished through a series of questions written by the author(s) to test that readers have the tools needed to translate recommendations for diagnostic and therapeutic clinical care into clinical practice. Members of the AnnalsATS editorial board review these questions and edit these questions for clarity, educational content, and the quality of the evidence supporting the response to the question.

AnnalsATS CME Planners

Margaret M. Hayes, M.D.
Harvard Medical School, Boston, MA, USA
Dr. Hayes reported receiving payments as an author for a chapter on heliox for UpToDate.
Caroline Okorie, M.D., M.P.H.
Stanford University School of Medicine, Stanford, CA, USA
Dr. Okorie reported no financial relationships with ineligible companies.

All relevant financial relationships have been reviewed and mitigated.


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