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COPD

  • by Paul Armentano, NORML Deputy Director January 30, 2018

    Long-term exposure to cannabis smoke is not associated with adverse effects on pulmonary function, according to clinical data published in the journal Chronic Obstructive Pulmonary Diseases.

    A team of investigators led by researchers at the Colorado School of Public Health assessed the relationship between marijuana use and respiratory function and symptoms in a cohort of 2,300 subjects ages 40 to 80, many of whom also smoked tobacco.

    Authors reported, “Neither current nor former marijuana use was associated with increased risk of cough, wheeze, or chronic bronchitis when compared to never marijuana users after adjusting for covariates. … Current and former marijuana smokers had significantly higher FEV1 (forced expiratory volume) … when compared to never users. … Both current and former marijuana use was associated with significantly less quantitative emphysema … when compared to never users, even after adjusting for age, … current tobacco smoking pack years, and BMI. … In agreement with other published studies, we also did not find that marijuana use was associated with more obstructive lung disease.”

    The long-term combined use of tobacco and cannabis also was not found to be associated with any additive adverse effects on the lungs. Authors concluded, “Among older adults with a history of tobacco use, marijuana use does not appear to increase risk for adverse lung function. … There may be no to little increased risk of marijuana use for a further increase in respiratory symptoms or adverse effects on lung function among those with a history of concomitant tobacco use.”

    Prior longitudinal studies assessing the effects of long-term cannabis smoke exposure on lung function have similarly reported that subjects’ marijuana use history is not positively associated with increased incidences of chronic obstructive pulmonary disease (COPD), lung cancer, or with other significant detrimental effects on pulmonary function.

    Full text of the study, “Marijuana use associations with pulmonary symptoms and function in tobacco smokers enrolled in the subpopulations and intermediate outcome measures in COPD Study (SPIROMICS),” appears online here.

  • by Paul Armentano, NORML Deputy Director January 14, 2015

    Study: Long Term Cannabis Exposure Not Associated With Significant Effects On Lung FunctionThe inhalation of one marijuana cigarette per day over a 20-year period is not associated with adverse changes in lung health, according to data published online ahead of print in the journal Annals of the American Thoracic Society.

    Investigators at Emory University in Atlanta assessed marijuana smoke exposure and lung health in a large representative sample of US adults age 18 to 59. Researchers reported that cannabis exposure was not associated with FEV1 (forced expiratory volume) decline or deleterious change in spirometric values of small airways disease.

    Authors further reported that marijuana smoke exposure may even be associated with some protective lung effects among long-term smokers of tobacco. Investigators acknowledged, “[T]he pattern of marijuana’s effects seems to be distinctly different when compared to that of tobacco use.”

    Researchers also acknowledged that habitual cannabis consumers were more likely to self-report increased symptoms of bronchitis, a finding that is consistent with previous literature. Separate studies indicate that subjects who vaporize cannabis report fewer adverse respiratory symptoms than do those who inhale combustive marijuana smoke.

    Authors concluded, “[I]n a large representative sample of US adults, ongoing use of marijuana is associated with increased respiratory symptoms of bronchitis without a significant functional abnormality in spirometry, and cumulative marijuana use under 20 joint-years is not associated with significant effects on lung function.”

    This study is the largest cross-sectional analysis to date examining the relationship between marijuana use and spirometric parameters of lung health.

    A separate study published in 2012 in The Journal of the American Medical Association (JAMA) similarly reported that cumulative marijuana smoke exposure over a period of up to 7 joint-years (the equivalent of up to one marijuana cigarette per day for seven years) was not associated with adverse effects on pulmonary function.

    A 2013 review also published in the Annals of the American Thoracic Society acknowledged that marijuana smoke exposure was not positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease. It concluded: “[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function. Findings from a limited number of well-designed epidemiological studies do not suggest an increased risk of either lung or upper airway cancer from light or moderate use. … Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”

    You may view an abstract of the study, “Effects of marijuana exposure on expiratory airflow: A study of adults who participated in the US National Health and Nutrition Examination Study,” here.

  • by Paul Armentano, NORML Deputy Director July 9, 2013

    Pulmonary complications associated with the regular smoking of cannabis are “relatively small” and far lower than those associated with tobacco smoking, according to a recent review published in the June edition of the scientific journal Annals of the American Thoracic Society.

    The paper – authored by Donald P. Tashkin, MD, emeritus professor of medicine and medical director of the Pulmonary Function Laboratory at the David Geffen School of Medicine at University of California, Los Angeles – is “the most comprehensive and authoritative review of the subject ever published,” according to an accompanying commentary. Donald Tashkin conducted US-government sponsored studies of marijuana and lung function for over 30 years.

    His review finds that although smoking cannabis may be associated with symptoms of chronic bronchitis, studies do not substantiate claims that it is positively associated with the development of lung cancer, chronic obstructive pulmonary disease (COPD), emphysema, or bullous lung disease.

    “[H]abitual use of marijuana alone does not appear to lead to significant abnormalities in lung function,” Tashkin writes. “[F]indings from a limited number of well-designed epidemiological studies do not suggest an increased risk of either lung or upper airway cancer from light or moderate use. … Overall, the risks of pulmonary complications of regular use of marijuana appear to be relatively small and far lower than those of tobacco smoking.”

    Writing in an accompanying commentary, McGill University’s Dr. Mark Ware concludes: “Cannabis smoking is not equivalent to tobacco smoking in terms of respiratory risk. … [C]annabis smoking does not seem to increase risk of chronic obstructive pulmonary disease (COPD) or airway cancers. In fact, there is even a suggestion that at low doses cannabis may be protective for both conditions. … This conclusion will affect the way health professionals interact with patients, parents with teenagers, and policy makers with their constituents. … Efforts to develop cleaner cannabinoid delivery systems can and should continue, but at least for now, [those] who smoke small amounts of cannabis for medical or recreational purposes can breathe a little bit easier.”

    Full text of the study, “Effects of marijuana smoking on the lung,” appears in Annals of the American Thoracic Society.

  • by Paul Armentano, NORML Deputy Director June 19, 2013

    A forthcoming review to be published in journal Annals of the American Thoracic Society reiterates that the ingestion of cannabis smoke poses nominal pulmonary risks compared to those associated with tobacco smoke. The author of the paper, Donald P. Tashkin, MD, emeritus professor of medicine and medical director of the Pulmonary Function Laboratory at the David Geffen School of Medicine at University of California, Los Angeles performed US-government sponsored studies of marijuana and lung function for over 30 years.

    A preview of Dr. Tashkin’s forthcoming review appears on the American Thoracic Society news website here. It reads:

    Dr. Tashkin found that regular smoking of marijuana by itself causes visible and microscopic injury to the large airways that is consistently associated with an increased likelihood of symptoms of chronic bronchitis that subside after cessation of use. He also found that the evidence does not indicate that habitual use of marijuana leads to significant abnormalities in lung function when assessed either cross-sectionally or longitudinally, except for possible increases in lung volumes and modest increases in airway resistance of unclear clinical significance.

    The author finds no clear link between marijuana use and the development of COPD or lower respiratory tract infections. In addition, “findings from a limited number of well-designed epidemiological studies do not suggest an increased risk for the development of either lung or upper airway cancer from light or moderate use, although evidence is mixed concerning possible carcinogenic risks of heavy, long-term use,” Dr. Tashkin notes. “In summary, the accumulated weight of evidence implies far lower risks for pulmonary complications of even regular heavy use of marijuana compared to the grave pulmonary consequences of tobacco.”

    The full paper will be available later this month.

    In May, presenters at the annual meeting of the American Academy for Cancer Research reported that subjects who regularly inhale cannabis smoke possess no greater risk of lung cancer than do those who consume it occasionally or not at all — according to an analysis of six case-control studies, conducted between 1999 and 2012, involving over 5,000 subjects (2,159 cases and 2,985 controls) from around the world.

    Last year, clinical data published in the Journal of the American Medical Association (JAMA) reported that subjects’ exposure to moderate levels of cannabis smoke, even over the long-term, is not associated with significant adverse effects on pulmonary function.

    Vaporizers, which heat marijuana to a point where cannabinoid vapors form, but below the point of combustion, reduce subjects’ intake of potentially hazardous combustible compounds. In several clinical trials, investigators have concluded that vaporization is a “safe and effective” cannabinoid delivery mode that “does not result in exposure to combustion gases.” Researchers also report that vaporization results in higher plasma concentrations of THC compared to smoked cannabis.