BETHESDA, MD – Without action by Congress, the United States could expect to have 7 million more uninsured by 2010, bringing the total somewhere near 52 million, according to a new study published Thursday in Health Affairs.

According to researchers Todd Gilmer and Richard Kronick of the University of California, San Diego (UCSD), rising health care costs and sluggish growth in personal incomes will add at least 6.9 million non-elderly Americans to the ranks of the uninsured by 2010.  Among workers not covered by a dependent or by a public program, the fraction who are uninsured is expected to increase sharply, rising 2.1 percentage points between 2007 and 2010 and reaching 26.4 percent in 2010, according to the Gilmer-Kronick study.

Gilmer and Kronick based their study on a healthcare coverage affordability index that takes into account employment characteristics such as firm size, industry, and self-employment and part-time status, as well as demographic and socioeconomic characteristics such as age, sex, marital status, race and ethnicity, education, and home ownership.

After using their index to derive predictions for uninsurance rates among workers, Gilmer and Kronick used the historical relationship between coverage rates for workers and for all non-elderly adults to generate predicted uninsurance rates for all non-elderly adults.

Gilmer said their estimates are likely to be low because of the number of Americans who have lost their jobs or will lose them in the coming months.

"In the recently enacted economic stimulus legislation, Congress provided a 65 percent subsidy toward continuation coverage for a subset of laid-off workers," Gilmer said. "That will help, but our research demonstrates once again the importance of more comprehensive action to extend adequate and affordable health coverage to all Americans."

The study comes as Congress is debating healthcare reform that congressional leaders have said they hope to pass by late June.