EUGENE, Ore. — Marijuana use by college students in Oregon has increased since it was legalized in 2015, more so than among college students in states where pot remains illegal, according to an Oregon State University study.

Building on a smaller study released last year, OSU researchers said college students at two large universities in the state are reporting more marijuana use since legalization. The increase includes more pot use by underage students. Researchers didn’t disclose the names of the two state schools.

“What’s happening in Oregon might be relevant to other states that have legalized marijuana or are considering doing so,” said David Kerr, the study’s lead author and an associate professor at OSU.

The legal age for marijuana use in Oregon is 21.

Around the country, marijuana use is on the rise among college students, according to the study, published this week in the journal Psychology of Addictive Behaviors. But the increase is higher in Oregon than in states where pot isn’t legal, according to OSU. The new study relies on a larger data set than last year’s study published in the journal Addiction.

“The results just seem to be more clear in that there were increases in the Oregon students,” Kerr said.

OSU researchers compared college student marijuana use data from the National College Health Assessment survey collected between 2008 and 2016. College students take the survey anonymously at universities and colleges around the country. The study focused on responses from undergraduates age 18 to 26 at two large public universities in Oregon and 123 schools in states where marijuana had not been legalized. None of the institutions was identified in the study.

In all, researchers evaluated about 280,000 surveys for the new study, according to OSU, compared to just under 11,000 from the same age group for the initial study. The previous study only had data from one university in Oregon and compared it to six other schools.

The new study indicated that, nationwide, marijuana use is more common among students who are white, male, living off campus or under age 21.

Kerr said the uptick in marijuana use by underage students “may be an unintended side effect of legalization.”

Harold Bae, co-author of the study and another assistant professor at OSU, said the latest study reflects immediate changes in marijuana use just after legalization.

“We recently received grant funding to examine longer term effects, including in other states that have legalized recreational marijuana,” he said.