About 45 percent of Alaskans could be denied health care coverage if health reforms passed into law last year are repealed, according a report released Tuesday morning by the White House. A look at the numbers comes on the same day Republicans in the House of Representatives begin their effort to block "government takeover of health care."

The analysis, which shows 318,000 Alaskans -- all with some kind of pre-existing medical condition -- are at risk of losing access to coverage, was released through Health and Human Services Secretary Kathleen Sebelius. The Affordable Care Act will guarantee access to coverage in 2014, and in the meantime a stop-gap program called the Pre-existing Condition Insurance Plan is already giving many previously uninsurable people access to care until the health reforms kick in, according to the report.

The numbers are based on data that indicate one in two non-elderly Americans -- or as many as 129 million people across the nation -- are at risk of losing health insurance when they need it most.

Heart disease, high blood pressure, arthritis and cancer are types of pre-existing conditions that have in the past caused insurance companies to either jack up rates, limit or deny coverage altogether. New health care laws passed in 2010 are, by 2014, designed to end discriminatory decisions based on pre-existing conditions. "Repealing the law would once again leave millions of Americans worrying about whether coverage will be there when they need it," Sec. Sebelius said Tuesday in a prepared statement.

The state of Alaska, meanwhile, is one of 26 states that have joined in a lawsuit challenging the health care reforms passed last year.

Contact Jill Burke at jill(at)alaskadispatch.com.