As the nation struggles to improve medical and mental health care for military personnel returning from Afghanistan and Iraq, about 1.8 million U.S. veterans under age 65 lack even basic health insurance or access to care at Veterans Affairs hospitals, a new study has found.

The ranks of uninsured veterans have increased by 290,000 since 2000, said Stephanie J. Woolhandler, the Harvard Medical School professor who presented her findings yesterday before the House Committee on Veterans Affairs. About 12.7 percent of non-elderly veterans - or one in eight - lacked health coverage in 2004, the most recent year for which figures are available, she said, up from 9.9 percent in 2000. Veterans 65 and older are eligible for Medicare.

About 45 million Americans, or 15 percent of the population, were uninsured in 2005, the Census Bureau reports.

"The data is showing that many veterans have no coverage and they're sick and need care and can't get it," said Woolhandler.