While combination antiretroviral therapy has significantly decreased the likelihood of lung disease morbidity and mortality among people living with HIV, it remains a common comorbidity in the patient population, which has higher rates of incidence than uninfected individuals. Higher prevalence of tobacco smoking has previously been indicated as a likely cause behind the increased risk, and now new research is suggesting that marijuana also plays a role.
According to the study, men living with HIV are more likely to develop lung disease from long-term marijuana smoking compared with men without infection, which suggests that healthcare providers can have a critical role
in reducing the risk of certain lung diseases in the patient population by educating them on the risks of marijuana smoking.
“Smoked cannabis is a potential risk factor for lung disease, as it contains many of the same toxic constituents present in tobacco smoke,” explained the researchers. “In the US, the proportion of HIV+ individuals who frequently smoke marijuana is higher than in the general population and has increased in recent years.”
Drawing on data from the Multicenter AIDS Cohort Study, the researchers identified 1352 men living with HIV and 1352 HIV-negative men from biannual study visits between 1996 and 2014. Approximately one-fourth (27%) of men with HIV and 18% of uninfected men reported daily or weekly smoking for at least a year, with a median of 4 years.
The researchers observed that among the men living with HIV, those who reported smoking were more likely to report one or more infectious or noninfectious pulmonary diagnosis compared with nonsmokers (41% vs 30% and 24.8% vs 19%, respectively). The increased risk remained independently of tobacco smoking or other risk factors, and the risk increased even further if they smoked both marijuana and tobacco.
Meanwhile, there was no link between marijuana smoking and infectious or noninfectious pulmonary diagnosis among the uninfected men (24.2% and 20.9% and 14.8% vs 17.7%, respectively).
There are several potential reasons behind this increased risk, the researchers explained, including lung immune cell depletion and dysfunction, persistent immune cell activation, systemic inflammation, respiratory microbiome alterations, and oxidative stress associated with HIV, or a combination of these effects with modifiable risk factors like marijuana.
“Previous studies linked marijuana smoke with alveolar macrophage dysfunction in both humans and mouse models, and a potential additive risk of marijuana smoking and HIV disease may explain the increased prevalence of infectious pulmonary diagnoses in our adjusted analyses,” they added.
Lorenz D, Uno H, Wolinsky S, Gabuzda D. Effect of marijuana smoking on pulmonary disease in HIV-infected and uninfected men: a longitudinal cohort study [published online January 24, 2019]. EClinicalMedicine
. doi: 10.1016/j.eclinm.2019.01.003