HONOLULU -- Native Americans may have higher rates of attempted suicide than other ethnic groups, but differences disappear when controlling for mental illness and sociodemographic factors, researchers said here.
In fact, risk of attempted suicide was nearly equalized across all racial groups -- whites, blacks, Hispanics, Native Americans, and Asians -- when controlling for these factors, reported Shay-Lee Bolton, PhD, of the University of Manitoba in Winnipeg, during an oral session at the American Psychiatric Association meeting.
"Investigating rates of suicide attempts doesn't provide a clear indication or risk among racial or ethnic groups," Bolton said. "But the presence of a mental disorder is clinically relevant when examining risk for suicide attempts in all groups."
Suicide is a major public health problem in the U.S., with 34,000 deaths in 2007, the last year for which data were available, Bolton said. Prevention is a top priority, but the factors that drive patients to such attempts are unclear, particularly the relationship between ethnicity and suicidal behavior.
In fact, some studies have shown a higher risk among whites compared with blacks or Hispanics, while others have found the exact opposite. A recent report from the Centers for Disease Control and Prevention found that Native Americans had the highest rates of suicide among all ethnic groups in the U.S.
Bolton noted, however, that previous studies had limited sample sizes and have not included all of the key racial-ethnic groups that are represented in the U.S.
So she and colleagues looked at data from the National Epidemiologic Survey on Alcohol and Related Conditions in 34,653 patients, ages 20 and up. The data came in two waves: 2001-2002 and 2004-2005, and the idea was to look at the prevalence and correlates of suicide attempts in a large, representative, and ethnically diverse sample of the general population.
All patients were interviewed in person, and they self-reported their race as white, black, Hispanic, Native American, or Asian. They were also asked to report any lifetime suicide attempts.
Like the latest CDC report, Bolton and colleagues found that Native Americans had the highest rates of attempted suicide at 6.5%, which was more than double that of whites, blacks, and Hispanics, who each reported a prevalence of around 3%.
Asians had the lowest percentage at 2%.
They also saw that across almost all racial groups, attempted suicide rates were two to three times greater for females than males, except among Asians, who had no sex differences in suicide rates, Bolton said.
Contrary to what the researchers expected, those who were foreign-born were less likely to attempt suicide than those born in the U.S., except among Asians, who were more likely to attempt suicide if they had migrated to the U.S.
Bolton called this finding interesting and novel given that many people think immigrants "may be more vulnerable, but in this case it seems they're somewhat protected."
Across all groups, suicide risk increased with decreasing income and increased with greater prevalence of mental disorders, Bolton said.
If they had any lifetime Axis I or II disorders, whites were 15 times more likely to have attempted suicide, Asians were 12 times more likely, Hispanics nine times, and blacks six times, Bolton said.
She added that the risk wasn't increased for Native Americans with mental disorders, nor was it increased for those of them with substance abuse and nicotine dependence. But Bolton noted that may have something to do with the baseline rates of these issues in that population.
"They have a higher prevalence of mental disorders, so when you adjust for that, they're no longer at increased risk," she said.
When controlling for all of these factors together -- lifetime mental disorder, nicotine and substance dependence, and sociodemographic conditions -- the risk across all racial or ethnic groups was essentially equalized, except among blacks who had a slightly lower risk than other groups (OR 0.7, 95% CI 0.6 to 0.9, P<0.01)
Bolton concluded that the results don't show a clearly increased risk of suicide based on racial or ethnic characteristics alone. Rather, the prevalence of mental disorder history and sociodemographic factors may be clinically relevant when examining the risk for suicide attempts, she said