More than half of the experts hired to advise the government on the safety and effectiveness of medicine have financial relationships with the pharmaceutical companies that will be helped or hurt by their decisions, a USA TODAY study found.

These experts are hired to advise the Food and Drug Administration on which medicines should be approved for sale, what the warning labels should say and how studies of drugs should be designed.

The experts are supposed to be independent, but USA TODAY found that 54% of the time, they have a direct financial interest in the drug or topic they are asked to evaluate. These conflicts include helping a pharmaceutical company develop a medicine, then serving on an FDA advisory committee that judges the drug.

The conflicts typically include stock ownership, consulting fees or research grants.

Federal law generally prohibits the FDA from using experts with financial conflicts of interest, but the FDA has waived the restriction more than 800 times since 1998.

These pharmaceutical experts, about 300 on 18 advisory committees, make decisions that affect the health of millions of Americans and billions of dollars in drugs sales. With few exceptions, the FDA follows the committees' advice.

The FDA reveals when financial conflicts exist, but it has kept details secret since 1992, so it is not possible to determine the amount of money or the drug company involved.

A USA TODAY analysis of financial conflicts at 159 FDA advisory committee meetings from Jan. 1, 1998, through last June 30 found:

• At 92% of the meetings, at least one member had a financial conflict of interest.
• At 55% of meetings, half or more of the FDA advisers had conflicts of interest.
• Conflicts were most frequent at the 57 meetings when broader issues were discussed: 92% of members had conflicts.
• At the 102 meetings dealing with the fate of a specific drug, 33% of the experts had a financial conflict.

"The best experts for the FDA are often the best experts to consult with industry," says FDA senior associate commissioner Linda Suydam, who is in charge of waiving conflict-of-interest restrictions.

But Larry Sasich of Public Citizen , an advocacy group, says, "The industry has more influence on the process than people realize."