A wall of wealth in the suburbs of Bridgeport and Stamford appears to have staved off the ravages of poverty sweeping through hinterlands in other states.

The Brookings Institution said in a new report Wednesday that 9.5 percent of the suburban U.S. population lived below the poverty line in 2008, while suburban Fairfield County had a poverty rate of just 5 percent.

"The suburban poor has held pretty steady" in Fairfield County, said Brookings Senior Research Analyst Elizabeth Kneebone, the study's lead author. The county has the second lowest suburban poverty rate in the nation.

For purposes of the study, the suburbs include all the municipalities in Fairfield County, except Bridgeport and Stamford. The two major cities' poverty rate in 2008 totaled 17 percent, up 3.4 percentage points from 2000 to 2008. The increase was well above the national average. The suburban Fairfield County poverty rate was 5 percent, an increase of 0.8 points, slightly below the national average.

Nationally, the urban poverty rate in 2008 was 18.2 percent, up two-tenths of a point from 2000, while the suburban rate shot up a whole point to 9.5 percent in 2008.

According to Brookings, which used Census Bureau data, nationally there were more people living below the poverty line in the suburbs in 2008 than there were in the central cities. In 2000, that was not the case.

Hartford, with 33 percent of the population below the poverty line in 2008, had the highest poverty rate of any major urban center in the country, according to Brookings.

Kneebone said that in raw numbers, there were about 31,000 people living in poverty in Fairfield County suburbs, which creates some difficulties unique to those communities beyond the central cities. She said the poor in the suburbs are spread out, which can make it difficult to provide services that are more accessible in cities.

That's a problem other parts of the country are going to have to deal with sooner rather than later, Kneebone said, as suburbs in other states are seeing the number of poor grow at a more rapid pace than in the cities. Not only are suburban families seeing their income hurt because of job losses and cuts in working hours, she said, but also because workers landing the low-paying jobs that have migrated to the suburbs are moving there from the cities to be near those jobs.

Kneebone said earlier studies indicate that the poor in the suburbs don't know what services are available to help them, so local organizations will have to do more outreach to combat this. Brookings is studying the issue to try to pinpoint further causes for these trends, she said.

A big reason the Fairfield County suburbs might be fending off the trend hitting the rest of the nation lies in the income of its residents.

According to the U.S. Census Bureau, seven of the suburbs in the county had median 2008 incomes of more than $100,000, including Fairfield and Trumbull. Ridgefield and Newtown posted medians of more than $113,000 in 2008, while Greenwich and Darien were above $126,000. Westport had a median income of $148,957 in 2008.

Among the cities, Stamford had a high median income of $77,598, the bureau said. Norwalk's median was $76,356, and Danbury's median income was $66,888 in 2008. The median income of Bridgeport, the most populous city in the state and county, in 2008 was $41,210,

Nick Perna, an economic advisor to Webster Bank and lecturer in economics at Yale University, said wealth plays a role in keeping Fairfield County's suburban poverty rate low.

"Say a guy doesn't get his bonus in 2008, his income drops from $1 million to $500,000 in Greenwich. That's not below the poverty line," Perna said.

He also said many families in the suburbs of Connecticut are older and have sources of income other than a job. That means if one of the breadwinners loses employment, the family could still have sizeable income generated from investments, he said.

And, Perna pointed out, though the state has been hit by the recession, Connecticut's unemployment rate is 2 points lower than the national rate.