CHICAGO -- Suicide attempts by gay teens and even straight kids are more common in politically conservative areas where schools don't have programs supporting gay rights, a study involving nearly 32,000 high school students found.

Those factors raised the odds and were a substantial influence on suicide attempts even when known risk contributors like depression and being bullied were considered, said study author Mark Hatzenbuehler, a Columbia University psychologist and researcher.

His study found a higher rate of suicide attempts even among kids who weren't bullied or depressed when they lived in counties less supportive of gays and with relatively few Democrats. A high proportion of Democrats was a measure used as a proxy for a more liberal environment.

The research focused only on the state of Oregon and created a social index to assess which outside factors might contribute to suicidal tendencies. Other teen health experts called it a powerful, novel way to evaluate a tragic social problem.

"Is it surprising? No. Is it important? Yes," said Dr. Robert Blum of Johns Hopkins' Bloomberg School of Public Health.

The study "takes our relatively superficial knowledge and provides a bit more depth. Clearly, we need lots more understanding, but this is very much a step in the right direction," he said.

Blum serves on an Institute of Medicine committee that recently released a report urging more research on gay health issues. Blum said the new study is the kind of research the institute believes has been lacking. The independent group advises the government on health matters.

The new study was published online Monday in the journal Pediatrics.

Previous research has found disproportionately high suicide rates in gay teens. One highly publicized case involved a Rutgers University freshman who jumped off a bridge last year after classmates recorded and broadcast the 18-year-old having sex with a man.

The study relied on teens' self-reporting suicide attempts within the previous year. Roughly 20 percent of gay, lesbian and bisexual teens said they had made an attempt, versus 4 percent of straight kids.

The study's social index rated counties on five measures: prevalence of same-sex couples; registered Democratic voters; liberal views; schools with gay-straight alliances; schools with policies against bullying gay students; and schools with antidiscrimination policies that included sexual orientation.

Gay, lesbian and bisexual teens living in counties with the lowest social index scores were 20 percent more likely to have attempted suicide than gays in counties with the highest index scores. Overall, about 25 percent of gay teens in low-scoring counties had attempted suicide, versus 20 percent of gay teens in high-scoring counties.

Among straight teens, suicide attempts were 9 percent more common in low-scoring counties. There were 1,584 total suicide attempts, 304 of those among gays, lesbians and bisexuals.

Hatzenbuehler said the results show that "environments that are good for gay youth are also healthy for heterosexual youth."

The study is based on 2006-08 surveys of 11th-graders that state health officials conducted in Oregon classrooms; Oregon voter registration statistics; Census data on same-sex couples; and public school policies on gays and bullying.

The researchers assessed proportions of Democrats versus Republicans; there were relatively few Independents. Information on non-voters wasn't examined.

Zachary Toomay, a high school senior from Arroyo Grande, California, said the study "seems not only plausible, but it's true."

The star swimmer, 18, lives in a conservative, mostly Republican county. He's active in his school's gay-straight alliance, and said he'd never been depressed until last year when classmates "ostracized" him for being vocal about gay rights.

Toomay said signs of community intolerance, including bumper stickers opposing same-sex marriage, also made him feel down, and he sought guidance from a school counselor after contemplating suicide.

Funding for the study came from the National Institutes for Health and a center for gay research at the Fenway Institute, an independent Harvard-affiliated health care and research center.

Michael Resnick, a professor of adolescent mental health at the University of Minnesota's medical school, said the study "certainly affirms what we've come to understand about children and youth in general.

"They are both subtly and profoundly affected by what goes around them," he said, including the social climate and perceived support.