by the Center for Responsive Politics found that health professionals — a category dominated by doctors — rank among the top 10 sources of campaign dollars for all but two of the panel's members.

The center ranks contributions to lawmakers from political action committees and individuals associated with more than 80 industries, from defense contractors to energy to farming.

The study of health care money, conducted for The Associated Press, found that four big industry sectors accounted for more than $17 million in campaign donations to the lawmakers since 1989.

After doctors, drug companies and makers of health products were the second-largest health care donors in the analysis. They were among the top 20 sources of campaign funds for nine of the panel members.

Hospitals and nursing homes were among the top20 sources of contributions for eight members, and health insurers were in the top 20 for five lawmakers.

The supercommittee is scheduled to hold its first meeting Thursday. Major changes to Medicare and Medicaid are needed to stabilize federal deficits, but it's an area fraught with political risk.

The two programs serve 100 million elderly, low-income and disabled Americans at a cost of more than $750 billion a year, a growing share of the budget.

The panel has wide latitude to propose changes, including shifting costs to beneficiaries, putting a limit on health care spending and placing hospitals and doctors on an austerity budget.

The same law that created the bipartisan panel of six Democrats and six Republicans calls for automatic spending cuts if the committee falls short.

For Medicare, that could add