WASHINGTON — A new study estimates that health costs for Iraq and Afghanistan veterans could top $900 billion, and a lawmaker wants to set up a trust fund to make sure the bill will be paid.

Rep. Bob Filner, D-Ca., warned that the U.S. faces a huge bill for veterans’ health care, and his concerns were buttressed by a recent study by Nobel Laureate Joseph Stiglitz of Columbia University and Linda Bilmes of Harvard University.

The two academics say the number of veterans, their injury rates and the cost of treating them have increased far more than expected in the last couple of years.

“If Americans want to vote for war, the Congress wants to vote for war, that’s fine – but include the real costs” and budget for them, Filner told reporters by phone Wednesday. Filner is chairman of the House Veterans Affairs Committee, which has scheduled a hearing on the issue Thursday.

Stiglitz and Bilmes, also speaking by phone, on Wednesday estimated the cost of providing vets with lifetime medical costs and disability payments from the Veteran’s Administration, as well as Social Security payments for the severely disabled, at between $589 billion and $934 billion, depending on the length and intensity of the Iraq and Afghan wars.

That is more than 30 percent higher than the Stiglitz and Bilmes estimated in the 2008 book “The Three Trillion Dollar War.”

They said that about 600,000 of the more than 2.1 million service members who’ve been deployed since 2001 have already received treatment by the Department of Veterans Affairs.

The 600,000 figure is far higher than the numbers most often given publicly by defense officials.

The veterans agency did not immediately respond to requests for comment.