A small but growing number of older adults are using marijuana, a trend that worries researchers who say not enough information exists about how pot affects those people.

Abundant research has been done on how the drug affects developing brains, but little is known about the consequences for older users, even as recreational pot has been legalized in a number of states.

Researchers at New York University say pot could pose such health challenges to older users as memory loss and an increased risk of falling.

In a new study, these researchers reviewed data from the National Survey on Drug Use and Health and found a big increase in people older than 50 reporting they had used pot in the past year.

A decade ago, about 2.8 percent said they had done so. In 2013, the rate was about 4.8 percent — a 71 percent jump.

“Historically, older people haven’t had high rates of substance use, but this is changing,” said Benjamin Han, an NYU geriatrician who led the study, which appears in the journal Addiction. “As baby boomers age, we’re going to see more and more of this.”

Older people are still much less likely than younger ones to use pot. In the 2013 survey, about 19 percent of people age 18 to 25 reported using marijuana in the previous month.

Doctors have little to go on when treating older pot users, Han said.

“When it comes to, for instance, alcohol, there have been a lot of studies about effects on older populations, guidelines on how much older people should be consuming,” Han said. “But when it comes to marijuana, we have nothing.”

The study drew no conclusions about whether older pot users were using the drug as medicine or for fun.

Surgeon General Vivek Murthy said last year that marijuana can be helpful for treating certain ailments, but he added that research on medical marijuana is preliminary, and he called for more studies.

Federal law considers marijuana a drug that has no medical use. Legalization debates often discuss the drug’s consequences for young people, perhaps leaving older adults to think there’s no downside to using it.

“Before the liberalization of marijuana policy, lots of young people used marijuana and then as they got jobs and kids and mortgages, they stopped,” said Jonathan Caulkins, a professor of public policy at Carnegie-Mellon University who was not involved in the NYU study.

“It seems that as the social stigmatization has decreased, more users are continuing into adulthood.”