February 4, 2019 - 18:38 AMT
Marijuana smoking "linked to lung disease among people with HIV"

In patients with HIV, long-term marijuana smoking is associated with lung disease independent of tobacco smoking, according to study findings.

“Given the high prevalence of marijuana smoking and increased risk of lung infections and other types of lung disease among people with HIV, it is important to know if long-term exposure to marijuana smoke has an impact on lung disease in this population,” Dana H. Gabuzda, MD, professor of neurology at Harvard Medical School and Dana-Farber Cancer Institute, told Infectious Disease News. “Previous studies that examined effects of marijuana smoking on lung health in people without HIV reported contradictory findings, and few studies examined its effects on lung health in HIV-positive persons.”

In a prospective cohort study, Gabuzda quantied lung disease risk among men enrolled in the Multicenter AIDS Cohort Study, a long-term observational cohort of HIV-infected and uninfected men who have sex with men. According to the study, all participants were aged 30 years or older and reported smoking marijuana and tobacco products between 1996 and 2014. According to the study, 1,630 pulmonary diagnoses were reported among 1,352 HIV-positive and 1,352 HIV-negative participants.

Results of the study showed that 27% of HIV-infected participants reported daily or weekly marijuana use for 1 or more years in follow-up, compared with 18% of uninfected participants. Additionally, HIV-infected participants had an increased likelihood of pulmonary diagnoses, and those who smoked marijuana faced an increased risk for infectious pulmonary diagnoses and chronic bronchitis compared with participants who were uninfected.

The most important finding of our study was higher rates of infectious lung diseases and chronic bronchitis in HIV-positive persons with long-term heavy marijuana smoking, regardless of tobacco smoking and other risk factors,” Gabuzda said. “By contrast, we did not find a significant effect of marijuana smoking in HIV-negative adults with similar age, race, and other demographic characteristics. These findings suggest HIV-infected individuals are more vulnerable to marijuana’s effects on lung infections and bronchitis compared to healthy uninfected individuals with similar exposures.”

Gabuzda said any type of smoking, including tobacco, marijuana or other, has the potential for negative effects on lung health because of toxic chemicals and smoke combustion products.

“We need more studies to evaluate the relative risks and benefits of nonsmoked vs. smoked forms of marijuana in different settings,” Gabuzda concluded. “In general, using marijuana in forms that [don’t] involve smoking is likely to be less harmful to a person's health, as long as the dose is the right amount to be safe.”