NEW YORK - The suicide rate among middle-aged Americans climbed a startling 28 percent in a decade, a period that included the recession and the mortgage crisis, the government reported Thursday.

The trend was most pronounced among white men and women in that age group. Their suicide rate jumped 40 percent between 1999 and 2010.

The rates in younger and older people held steady. And there was little change among middle-aged blacks, Hispanics, and most other racial and ethnic groups, the report from the Centers for Disease Control and Prevention found.

Why did so many middle-aged whites - ages 35 to 64 - take their own lives?

One theory suggests the recession caused more emotional trauma in whites, who tend not to have the same kind of church support and extended families that blacks and Hispanics do.

The economy was in recession from the end of 2007 until mid-2009. Even well afterward, polls showed most Americans remained worried about weak hirin and other problems.

Pat Smith, violence-prevention program coordinator for the Michigan Department of Community Health, said the recession - which hit manufacturing-heavy states particularly hard - may have pushed troubled people over the brink. Being unable to find a job or settling for one with lower pay could add "that final weight to a whole chain of events," she said.

'Upsurge'

Another theory notes that white baby boomers have always had higher rates of depression and suicide, and that has held true as they have hit middle age. During the 11-year period studied, suicide went from the eighth-leading cause of death among middle-aged Americans to the fourth, behind cancer, heart disease, and accidents.

"Some of us think we're facing an upsurge as this generation moves into later life," said Eric Caine, a suicide researcher at the University of Rochester.

One more possible contributor is the growing sale and abuse of prescription painkillers. Some people commit suicide by overdose. In other cases, abuse of the drugs helps put people in a frame of mind to attempt suicide by other means, said Thomas Simon, one of the authors of the CDC report, which was based on death certificates.

People ages 35 to 64 account for about 57 percent of suicides in this country.

The report contained surprising information about how middle-aged people kill themselves: During the period studied, hangings overtook drug overdoses in that age group, becoming the No. 2 manner of suicide. But guns remained far in the lead and were the instrument of death in nearly half of all suicides among the middle-aged in 2010.

In Pa. and N.J.

The CDC does not collect gun-ownership statistics and did not look at the relationship between suicide rates and the prevalence of firearms.

For the entire U.S. population, there were 38,350 suicides in 2010, making it the nation's 10th-leading cause of death, the CDC said. The overall national suicide rate climbed from 12 suicides per 100,000 people in 1999 to 14 per 100,000 in 2010. That was a 15 percent increase.

For the middle-aged, the rate jumped from about 14 per 100,000 to nearly 18 - a 28 percent increase. Among whites in that age group, it spiked from about 16 to 22 per 100,000.

Thirty-nine out of 50 states registered a statistically significant increase in suicide rates among the middle-aged.

In Pennsylvania, the number who committed suicide rose 23.8 percent from 1999 to 2010, to 17.4 per 100,000 residents. The state has the 10th-lowest rate.

In New Jersey, the increase was even higher - 31.3 percent - though the state has the second-lowest rate in the nation for the age group, 11.8 per 100,000 residents.