Gay and bisexual men are more likely than straight men to use indoor tanning, and almost as likely as women to engage in the dermatologically risky behavior, according to new research.

"We’re not surprised that there is more indoor tanning among gay and bisexual men, compared to straight men, but what is striking is that the absolute prevalence rivals that of straight women," said lead author Dr. Howa Yeung.

He and Dr. Suephy Chen, both dermatologists at Emory University in Atlanta, report in JAMA Dermatology that 5 percent of gay men and about 7 percent of bisexual men reported tanning in the last year, compared to less than 2 percent of straight men and about 7 percent of straight women.

Straight women have historically been considered the highest risk group for indoor tanning, Yeung told Reuters Health. "We really haven’t focused on men at all," he added.

The Centers for Disease Control and Prevention says that as many as 400,000 cases of skin cancer may be related to indoor tanning in the United States each year, including 6,000 melanomas, which are the deadliest type of skin cancer.

For the new study, the researchers used 2013 data that asked Americans about their sexual orientation and how often they used indoor tanning devices, like sun lamps, sun beds and tanning booths.

Gay and bisexual men were three times and five times, respectively, more likely than straight men to have tanned indoors within the past year. What's more they were about five and seven times, respectively, more likely to tan "frequently" than straight men.

Frequent tanning is the use of indoor tanning devices 10 or more times within the past year.

Among women, the researchers found no differences between gay, bisexual and straight women once they accounted for factors known to influence tanning behaviors, including age, race or ethnicity, education, income, health insurance status, where the person lives and her skin cancer history.

The study can't say why gay and bisexual men are more likely to tan indoors than straight men, but it may involve dissatisfaction with body image, Yeung said.

"More research needs to be done about why that is the case," he said.

Yeung also said they can't say whether the increased popularity of indoor tanning among gay and bisexual men translates into more cancers, because databases that track cancer don't ask about sexual orientation.

"With the recent national focus on gay marriage, there is more and more focus on gay, bisexual, lesbian and transgender (LGBT) health," Yeung said.

"As a dermatologist, I want to highlight some of these things and inform the LGBT population so we can improve their skin health," he added.