WASHINGTON —  More than a third of U.S. adults have bad debt that has been handed over to a collection agency and their average debt in collections is $5,178, according to a study published on Tuesday by the Urban Institute.

The authors of the report by the Washington, D.C.-based think tank said vicious cycles of bad debt can hold back families and entire communities.

“Most people wouldn’t blink if told that the majority of Americans carry some debt. But they would be shocked to learn that reported debt in collections is pervasive and threads through nearly all communities,” said Caroline Ratcliffe, a senior fellow at the Urban Institute. “Delinquent debt can harm credit scores, which can tip employers’ hiring decisions, restrict access to mortgages and even increase insurance costs.”

The study looked at a random sample of 7 million individual credit reports from TransUnion credit bureau – one of the three big credit reporting companies. That covers 3 percent of the adult population. The sort of debt in collections could be a credit card, medical or utility bill or a parking fine, but does not include mortgage debt.

There is a high concentration of people with debt in collections in Southern states. Alabama, Georgia, Mississippi, Louisiana all have 40 percent of people with a credit report have debt in collections but the level of debt is also relatively low in those states.

Nevada, hit hard by the housing crisis, “not only has the largest share of people with reported debt in collections (47 percent), it also has the highest average amount of debt in collections, among people with debt in collections ($7,198),” the study said.

Bad debt loads are probably higher than the data in the study indicate, because about 9 percent of U.S. adults do not have a credit file, are not represented in the study and are more likely to have financial trouble, the authors of the report said.

The study said the level of bad debt is unchanged from about 10 years ago when the Federal Reserve did a study of credit bureau data.