A large study in California released Monday found that cancer may be nearly twice as prevalent among gay men as among straight men.
The study relied on self-reported data from the California Health Interview survey, the largest state survey of its kind in the United States, and included more than 120,000 people over three years: 2001, 2003 and 2005.
A total of 3,690 men reported a cancer diagnosis as adults. Gay men were 1.9 times as likely as straight men to have been diagnosed with cancer, said the study published in the peer-reviewed journal Cancer.
There was no such difference witnessed among lesbian and straight women, but gay and bisexual females were twice as likely to say they were in fair or poor health after a cancer diagnosis compared to their heterosexual counterparts.
Lead author Ulrike Boehmer of the Boston University School of Public Health said the data can help guide services for the gay community.
"Because more gay men report as cancer survivors, we need foremost programs for gay men that focus on primary cancer prevention and early cancer detection," she said.
"Because more lesbian and bisexual women than heterosexual women with cancer report that they are in poor health, we need foremost programs and services that improve the well-being of lesbian and bisexual cancer survivors."
The survey did not address how cancer survival rates may differ among those of varying sexual orientation, and may not reflect a true difference in the actual cancer rate because it relied on data from survivors only.
But researchers believe that higher anal cancer rates, caused by the sexually transmitted human papillomaviruses, as well as complications from human immunodeficiency virus, may be at least partly to blame.
"The greater cancer prevalence among gay men may be caused by a higher rate of anal cancer, as suggested by earlier studies that point to an excess risk of anal cancer," said the study.
Researchers "did not have data available on the rate of human immunodeficiency virus (HIV) infection, which is higher among gay men, and may have contributed to the significant association of cancer prevalence and sexual orientation."
HIV and AIDS have been linked to a series of cancers including Kaposi sarcoma and non-Hodgkin lymphoma as well as anal, lung, testicular cancer and Hodgkin lymphoma.
More research is needed to determine if gay men are actually at a higher risk of getting cancer, the study author said.