Frequent cannabis smoking is a risk factor for lung disease in HIV-positive men, according to US research published in EClinicalMedicine. Smoking cannabis increased the risk of pulmonary diseases – especially those with an infectious cause – independent of smoking and CD4 cell count. The research involved approximately 2500 men who have sex with men (MSM), half of whom were HIV positive. No independent associations were detected between smoking cannabis and lung disease in HIV-negative men, showing that HIV-positive individuals are especially vulnerable to lung disease caused by smoking the drug, aidsmap says.
“To our knowledge, this study is the largest investigation of smoked marijuana [cannabis] and pulmonary diagnoses in HIV infected individuals to date,” comment the authors. “Current daily or weekly marijuana smoking was associated with elevated risk of infectious pulmonary diagnoses in HIV+ participants….current marijuana smoking was also associated with increased risk of chronic bronchitis.”
The authors believe their findings are of relevance to the care of people with HIV and that addressing smoked cannabis use could help reduce rates of pulmonary disease.
It is well known that people with HIV have an increased risk of lung disease. This is partly because of the high rates of smoking among HIV-positive individuals. However the damage caused by HIV infection and immune suppression are also important causes.
Research involving HIV-negative people has shown that smoking cannabis is a risk factor for respiratory symptoms such as cough and wheezing, as well as chronic obstructive pulmonary disease (COPD) and emphysema. However, relatively little is known about cannabis smoking as a risk factor for pulmonary disease in patients with HIV.
Investigators form the ongoing Multicenter AIDS Cohort Study (MACS) therefore designed a study comparing incidence of infectious lung diseases (such as pneumonia) and non-infectious pulmonary disease, especially bronchitis, between HIV-positive and HIV-negative gay and other MSM, after taking into account smoking of cannabis. Analyses also considered other risk factors for lung disease, especially tobacco smoking, and for patients with HIV, CD4 cell count.
The study population consisted of 2704 men aged 30 years and older. Half were HIV-positive. Participants were recruited between 1996 (the year combination ART was first introduced) and 2014. The average duration of follow-up was a little over ten years. Participants were asked about the frequency and intensity of smoking of cannabis and tobacco, as well as lung disease diagnoses (the latter were also verified using medical records).