For the first time, the health insurance industry is offering to curb its controversial practice of charging higher premiums to sick people.

The offer, in a letter the industry to key senators Tuesday, is a potentially significant shift in the debate over reforming the nation's health care system to curb costs and cover an estimated 48 million uninsured people.

In the letter, America's Health Insurance Plans and the Blue Cross and Blue Shield Association say they are willing to "phase out the practice of varying premiums based on health status in the individual market" if all Americans are required to get coverage.

Insurers are trying to head off creation of a government insurance plan that would compete with them.