Fall risk tied to cigarettes more than cannabis in aging adults with HIV

Older adults with HIV who use cannabis face a higher risk of falling than those who don't; however, that added risk lessens once cigarette smoking is factored in, according to a study recently published in Open Forum Infectious Diseases.

The analysis draws on ACTG A5322, also known as the HIV Infection, Aging, and Immune Function Long-Term Observational Study, a multicenter cohort that has followed adults aging with HIV at 32 research sites across the continental United States and Puerto Rico since 2013. A team of researchers, including corresponding author Jennifer A. Manuzak, Ph.D., of the Tulane National Biomedical Research Center, collected data of 957 participants with a median age of 51 who reported on current cannabis use and any falls at regular study visits.

People with HIV are living longer on effective antiretroviral therapy, and approximately 54% those diagnosed in the United States are now 50 or older. That aging population also uses cannabis at notably higher rates than people without HIV: past studies cited in the paper put lifetime cannabis use among people with HIV at roughly 77%, compared with about 45% among people without HIV. Cannabis use has also been climbing among older adults generally, with past-month use among adults 65 and older rising from 4.8% in 2021 to 7.0% in 2023.

What the study found

At baseline, 18.2% of participants reported cannabis use in the past month, and 18.6% reported a fall in the prior year. After adjusting for age, sex and race or ethnicity, current cannabis use was associated with a 27% higher risk of falling in the following year (risk ratio, 1.27). But when the researchers additionally adjusted for cigarette smoking status, prior falls, other substance use, prescribed medications, heavy alcohol use and peripheral neuropathy, that association weakened substantially and was no longer statistically significant (adjusted risk ratio, 1.11).

Why cigarette smoking mattered more

Compared with participants who had never smoked, those who currently smoked cigarettes had a 62% higher risk of falling, and those who had previously smoked had a 32% higher risk. Sensitivity analyses that looked at cannabis use over the past year, rather than the past month, produced nearly identical results.

The authors attribute this largely to smoking's links to inflammation and disease burden. Smoking is associated with elevated inflammation among people with HIV on antiretroviral therapy, which is tied to frailty and physical impairment, both established fall risk factors. Smokers are also more likely to have conditions such as diabetes and cardiovascular disease requiring additional medications, and polypharmacy independently raises fall risk. Cannabis, by contrast, has been linked to lower inflammation in prior HIV research, which may explain why its modest anti-inflammatory effect wasn't enough to offset smoking's impact.

Manuzak and her team noted several limitations, including that both cannabis use and falls were self-reported and that the study did not collect data on cannabis potency, dosing or method of use, which could influence fall risk in ways this analysis couldn't capture. They also cautioned that because A5322 participants were engaged in a long-running clinical research cohort with strong access to care, the findings may not fully generalize to all adults aging with HIV.

What it means for HIV care and payers

Falls are already a significant and growing cost driver for health plans and Medicare. Non-fatal falls among older adults cost the U.S. health care system approximately $80 billion a year, most of it paid by Medicare. As antiretroviral therapy extends life expectancy for people with HIV, more of that population is aging into higher fall-risk categories, making screening for modifiable risk factors like smoking and substance use increasingly relevant for payers managing this group.

“Cannabis use and cigarette smoking may therefore serve as indicators for risk stratification in the care of adults aging with HIV," Manuzak and her colleagues wrote in Open Forum Infectious Diseases. They added that future interventional research is needed to determine whether smoking cessation or changes in cannabis use could meaningfully reduce fall risk in this population.