LOS ANGELES - The homeless population of Los Angeles fell sharply during the past two years, a study released on Wednesday found, confounding expectations that the recession would drive more people into the city's streets and shelters.

Some credit went to better programs to keep people off the streets, but experts say the worst economic slump since the Great Depression may also have played a role as rents declined and created more affordable housing.

Others disputed that notion, asserting that recent waves of foreclosures invariably drive more people into homelessness.

According to the latest census performed every two years by the Los Angeles Homeless Services Authority, an estimated 43,000 people are living on the streets, in cars, in abandoned buildings or in shelters and government-funded transitional housing facilities on any given night in greater Los Angeles.

That count, conducted January 27-29, is down 38 percent from the 2007 tally but remains the largest homeless population of any metropolitan area in the United States, said Michael Arnold, executive director of the Homeless Services Authority.

The number and proportion of the homeless who are living on the streets was down, too, from 83 percent to about two-thirds of the total, while the number of families with children included in the tally also dropped substantially.

Arnold said the numbers reflect stepped-up local efforts to fight homelessness, including a $100 million initiative undertaken by Los Angeles County and a recent expansion of rental vouchers aimed at homeless families.

Still, Los Angeles, the second-largest U.S. city and home to a notorious downtown Skid Row, appears to be bucking a national trend.

While other areas across the country have seen similar declines in their homeless populations since 2007, most sizable cities are reporting increases, not decreases, said Nan Roman, president of the Washington-based National Alliance to End Homelessness.

She called the findings of the Los Angeles survey a little surprising, but agreed with Arnold that it was possible for a housing slump to have depressed rental rates, leading to an increase in lower-cost housing.

Arnold said that even rising unemployment could indirectly help lower homelessness, as a declining work force leads to higher vacancy rates, which drives down rents and creates more affordable dwellings.

What we expected was that people would lose their jobs, and then they would lose their homes and then they would become homeless, and the answer is that it's a lot more complicated than that, he said.

Some experts disputed the notion that the real estate crisis could help ease homelessness.

It's just a premise that we don't find holds water, said Neil Donovan, executive director of the National Coalition for the Homeless.

The truth is that there's an overall lack of affordable housing in this country, he said.

When you enter into bad economic times, the wealthy (and) medium-income people move into housing that is less expensive, and they start occupying units that would typically go to low-income people, drying up a resource of affordable housing.

Donovan's group and six other organizations recently issued a survey that found about 10 percent of homeless people assisted by social service agencies around the country over the past year had lost their homes due to foreclosure.

(Editing by Mary Milliken)