Respiratory Effects of Marijuana and Tobacco Use in a U.S. Sample


  • There are no possible conflicts of interest for any of the authors.

  • This article was presented in part at the June 12–17, 2003 annual scientific meeting of the College on Problems of Drug Dependence, Bal Harbour, FL.

Address correspondence and requests for reprints to Dr. Moore: Department of Psychiatry, Yale University School of Medicine, 219S CMHC-SAC, 34 Park Street, New Haven, CT 06519 (e-mail:


Objective: Although a number of studies have examined the respiratory impact of marijuana smoking, such studies have generally used convenience samples of marijuana and tobacco users. The current study examined respiratory effects of marijuana and tobacco use in a nationally representative sample while controlling for age, gender, and current asthma.

Design: Analysis of the nationally representative third National Health and Nutrition Examination Survey (NHANES III).

Setting: U.S. households.

Participants: A total of 6,728 adults age 20 to 59 who completed the drug, tobacco, and health sections of the NHANES III questionnaire in 1988 and 1994. Current marijuana use was defined as self-reported 100+ lifetime use and at least 1 day of use in the past month.

Measurements and Main Results: Self-reported respiratory symptoms included chronic bronchitis, frequent phlegm, shortness of breath, frequent wheezing, chest sounds without a cold, and pneumonia. A medical exam also provided an overall chest finding and a measure of reduced pulmonary functioning. Marijuana use was associated with respiratory symptoms of chronic bronchitis (P=.02), coughing on most days (P=.001), phlegm production (P=.0005), wheezing (P<.0001), and chest sounds without a cold (P=.02).

Conclusion: The impact of marijuana smoking on respiratory health has some significant similarities to that of tobacco smoking. Efforts to prevent and reduce marijuana use, such as advising patients to quit and providing referrals for support and assistance, may have substantial public health benefits associated with decreased respiratory health problems.