While anti-suicide campaigns have focused on teens and young adults because they are thought to be at high risk, a study in the online edition of the American Journal of Preventive Medicine concludes that middle-aged white men and women register the highest rate of suicide in the United States. Whites age 40 to 64 have “recently emerged as a new high-risk group for suicide,” the study says.

The study by Susan Baker, MPH, of the Johns Hopkins Bloomberg School of Public Health in Baltimore, and her colleagues, was based on data from 1999 to 2005. Suicide claimed 32,637 lives in 2005, a rate of 11 per 100,000 people. Overall, the suicide rate increased by 0.7 percent per year during that period, but it rose 2.7 percent annually among middle-aged white men and 3.9 percent among middle-aged white women.

"The results underscore a change in the epidemiology of suicide, with middle-aged whites emerging as a new high-risk group. Historically, suicide-prevention programs have focused on groups considered to be at highest risk -- teens and young adults of both genders as well as elderly white men. This research tells us we need to refocus our resources to develop prevention programs for men and women in their middle years,” Baker said in a statement.

On the other hand, suicide in blacks decreased significantly and remained stable among Asian and Native Americans.

The study also shows that rates of suicide by hanging or suffocation increased by 6.3 percent among men and 2.3 percent among women. Overall, the study found that hanging/suffocation accounted for 22 percent of all suicides by 2005, surpassing poisoning at 18 percent. Previous studies have showed that guns were the most common method of suicide. Other methods included prescription drugs, poisons, and firearms.

The researchers could not find a specific reason behind this increase in suicidal rates. Dr. Paula Clayton, research director of the American Foundation for Suicide Prevention said it might be associated with an increase in abuse of prescription pain pills, known to cause depression and expose people to suicidal thoughts. Another possible explanation was the drop in hormone replacement therapy after it was linked to health risks in 2002. Women who interrupted the drugs were more susceptible to depression and potentially suicide. However more study needs to be done in order to fully understand reasons behind this situation, Dr. Clayton, who was not involved in the study, said.

The bad news is that the suicidal rate could increase even more given the current economic situation in the US, the researchers warned.