Gay men in California are nearly twice as likely to report a cancer diagnosis as straight men in the state, according to new research published online Monday in the medical journal Cancer.

Few cancer studies investigate how sexual orientation might affect cancer risk and survivorship, often because study participants are not asked about their sexual orientation. In Monday's study, researchers used a large health survey conducted by the state of California - in which respondents were asked about their orientation - to examine the impact cancer may be having on gays and lesbians in the state.

The results show about 8% of gay men had experienced a cancer diagnosis, compared with only about 5% of straight men. Among straight women and lesbians, the cancer prevalence trends were more closely matched.

Researchers speculate the increased cancer prevalence among gay men is associated with HIV status.

"There's a higher prevalence of HIV positive men in the gay population, and we know that being HIV positive is related to cancers, so this might drive the differences we found," said study author Ulrike Boehmer, an associate professor at Boston University School of Public Health.

Anal cancer, lung cancer, testicular cancer and Hodgkin's lymphoma are more prevalent among men who are HIV positive, Boehmer said.

The study found gay men were also more likely to get cancer at a younger age than straight men – almost 10 years sooner – at the age of 41, on average.

Boehmer's findings show cancer may be having a different impact on lesbians.

"Those with cancer are twice a likely to report that they are in fair or poor health," she said, as compared with straight female survivors.

Why lesbian cancer survivors may perceive their health to be so poor is uncertain. Boehmer hopes her findings will help lead to more targeted cancer intervention programs to help lesbian cancer survivors overcome their health problems, as well as more targeted cancer prevention programs for gay men.