Condom use has dropped sharply since 2010 among a large share of students at the University of Minnesota, and sexually transmitted infections such as chlamydia and gonorrhea are on the rise.

In a new survey, 52 percent of students said they used a condom the last time they had vaginal intercourse, down from 60 percent in a survey five years ago. The share who said they used a condom for oral sex or anal sex has risen slightly, but remains far too low, U health officials said.

“Due to a combination of behavioral, biological and cultural reasons, sexually active young adults are at increased risk for acquiring sexually transmitted infections,” or STIs, the study said.

The new numbers leave condom use at the lowest level in recent memory, said Dave Golden, director of public health and communications at the U’s Boynton Health Service. “This is the first time we’ve ever seen this,” he said.

The study did not factor in students who were married or in domestic partnerships.

While the causes remain unclear, Golden speculated that students may be dropping their guard because of improved treatments for infections such as HIV, which has become less of a death sentence than it once was.

But the reasons, he said, matter less than the risks.

“There’s been a lot of people making a lot of guesses, and it’s just guesswork,” he said. “We’re just trying to get students to use condoms, and we want that number to go up.”

In some respects the U’s survey data run counter to other trends among Minnesota students.

A statewide survey of public school students by the Minnesota Department of Health found a sharp drop from 1992 to 2013 in pregnancies and the share of students having intercourse, as well as higher levels of condom use among those who were sexually active.

Nationally, however, STI rates are on the rise, according to the U.S. Centers for Disease Control and Prevention (CDC). Minnesota officials said the U may just now be catching up with national trends.

Still, Golden noted, some of the stereotypes of campus promiscuity are misplaced.

According to the U’s survey, 79 percent of students reported having one or no sexual partners in the last 12 months — lower than people in the same age group who aren’t in college.

Fewer than 2 percent of students surveyed said their last partner was a stranger.

STIs affect 15- to 24-year-olds more than other age groups, according to a 2014 report by the CDC. Two-thirds of the reported chlamydia and gonorrhea cases were from people in that age group.

‘Hookup’ apps

While the cause of rising infection rates remains murky, some public health officials are blaming dating apps and websites.

“It’s easy to automatically blame this really new way for people to find sex partners that didn’t exit a few years back,” said Sam Robertson, a risk reduction coordinator at the Minnesota AIDS Project.

While Robertson said apps allow people to find sexual partners more easily, they also provide health resources for people who didn’t receive proper sex education in school.

Tinder, a popular dating app, added a feature to locate STI testing after a billboard campaign by the AIDS Healthcare Foundation last year. The ads suggested “hookup” app users were at risk of contracting infections.

But the apps might also be leading to people having more sex in general, Robertson said, adding that poor sexual health education also contributes to unprotected sex and the spread of STIs, especially in young people.

Kathryn Luk, a neuroscience student and coordinator for SHADE, a student-run sexual health awareness group at the U, said that her group has some concerns about dating websites and apps, but that it focuses on more immediate concerns.

“We just recommend that no matter where they’re finding their sexual partner that they use protection,” Luk said. “Our goal is to see students use condoms 100 percent of the time, as unrealistic as that might be.”

Each year, she said, the group buys about 100,000 condoms to hand out to students, but Luk said some students are reluctant or embarrassed to come into Boynton to talk with SHADE members.

“For some people it’s hard to talk to a stranger about sex,” Luk said. “Our goal is trying to make it more openly discussed.”

Youssef Rddad is a University of Minnesota student on assignment for the Star Tribune.