Washington ? Providing health care for the uninsured increases the annual cost of insurance premiums for the average worker by $341 and for the average family by $922, according to a study by a group promoting universal health insurance.

Families USA, a Washington-based group that supports universal health care coverage, says its study shows the problem is not restricted to the tens of millions of uninsured Americans.

Rather, the problem affects everyone, because the insured subsidize the cost of care given the uninsured. Most economists agree that some amount of subsidizing occurs, but the question has been how much.

“The large and increasing number of uninsured Americans is no longer an altruistic concern for those without health coverage, but is a concern for all of us,” Ron Pollack, executive director of Families USA, said at a news conference.

Kansas Gov. Kathleen Sebelius, who was in Washington to take part in the conference, said the study showed how the costs of so many uninsured Americans burdened families and businesses.

“What Families USA has done for the first time is put that number on a health bill,” she said.

Sebelius said the study demonstrated the need for states to work with the federal government to expand the number of people receiving health care coverage.

She said the 300,000 uninsured residents of Kansas often received the most expensive, but least effective, health care because they were forced to wait until health problems got serious before seeking treatment.

Insurance premiums for the average Kansas family cost an extra $729 to pay for the uninsured, the study shows.

The study, prepared by Ken Thorpe, a professor at Emory University, concluded that about $1 out of every $12 spent on health insurance premiums indirectly pays for health care provided the uninsured.

The uninsured pay out of pocket about a third of the costs for their health care, the group said. Hospitals rely on charitable donations, government programs and the private sector to cover the rest.

Paul Ginsburg, an economist, said hospitals were having more success negotiating reimbursement rates with private insurers, and they took into account their costs for uncompensated care.

“Ten years ago, I might have been skeptical about a study like this, but in 2005, I’m not,” said Ginsburg, president of the Center for Studying Health System Change, an organization that provides nonpartisan analysis.

Increased costs could prompt employers to cut back on the health insurance they now provide.

“It’s a vicious circle that will not end until we as a nation take steps to solve the underlying problems,” the advocacy group said.

Families USA supports expanding health insurance coverage to all Americans, or universal coverage.

Uwe Reinhardt, a professor at Princeton University, said universal health coverage would raise costs even more for those currently insured.

Reinhardt said the uninsured would be likely to go to a doctor more frequently if they had coverage. He’s skeptical that taxpayers would be willing to pay the added cost.

From the purely economic perspective, he said, “leaving the uninsured is a bargain” for the insured.

While a trade group for insurers declined to comment on the specifics in the report, it did agree on the need to reduce the number of uninsured.

“This report shows there are many reasons for us to address the reasons for lack of insurance – one is to improve the health of the population and the other is to get a handle on the cost problem,” said Susan Pisano, spokeswoman for America’s Health Insurance Plans.