New study acquits marijuana of role in COPD
Smoked marijuana achieves different outcomes for different people: some smoke weed to relax while others use cannabis to medicate. Regardless of the rationale, the Journal Chronic Obstructive Pulmonary Disease revealed there is no direct correlation between prolonged exposure to marijuana smoke and adverse pulmonary function in a report released Tuesday.
In an attempt to drill down the controversial relationship between marijuana use and chronic obstructive pulmonary disease (COPD), a team of inquisitive scientists from the Colorado School of Public Health performed a cross-sectional analysis of 2,304 “current and former tobacco smokers” between the ages of 40 and 80.
Provided a lofty title, “Marijuana use associations with pulmonary symptoms and function in tobacco smokers enrolled in the Subpopulations and Intermediate Outcome Measures in COPD,” the SPIROMICS study scrutinized the perceived relationship between marijuana use and respiratory function.
Marijuana Use in “Joint Years”
“Marijuana lifetime exposure and current use status were assessed at enrollment (online supplement Table 1). Marijuana use was categorized into current (use in the past 30 days), and former (use over 30 days ago) users and compared to never users. Those with a history of marijuana use estimated the number of bowls or joint equivalents smoked per week and how many years the participant had smoked marijuana (one bowl was equated to one joint in this analysis). This information was used to calculate the number of joint years which was kept as a continuous variable; 1 joint year is equivalent to smoking 1 joint or bowl per day for one year. A supplementary analysis was added to assess the impact of joint-year history with lung function and symptoms. Joint years were categorized into <10, 10-20, and >20 joint-year history and compared to those who reported zero joint years.”
Results from the study concluded, “Neither current nor former marijuana use was associated with increased risk for cough, wheeze, or chronic bronchitis when compared to never marijuana users after adjusting for covariates.” While providing the caveat that these results “are likely heavily biased and should be interpreted with caution,” the study concluded that individuals exposed to long-term marijuana use had a lower percentage of emphysema, higher totals of lung tissue volume, and a higher percentage of air trapping, after compensating for covariates.
A study spanning two decades conducted by Dr. Donald Tashkin, a professor of medicine and co-director of the Asthma and Cough Center at UCLA, also concluded that long-term marijuana use does not impair lung function.
Main Photo Courtesy of Allie Beckett