CHICAGO — The American Medical Association is issuing a formal apology for more than a century of discriminatory policies that excluded blacks from participating in a group long considered the voice of American doctors.

The apology stems from initiatives at the nation’s largest doctors’ group to reduce racial disparities in medicine — from the paltry number of black physicians to the disproportionate burden of disease among blacks and other minorities.

It comes more than 40 years after AMA delegates denounced policies at state and local medical societies dating to the 1800s that barred blacks. For decades, AMA delegates resisted efforts to get them to speak out forcefully against discrimination or to condemn the smaller medical groups that historically have had a big role in shaping AMA policy.

The apology being issued today might seem belated, but it isn’t the AMA’s first for its discriminatory history. Dr. John Nelson, then AMA’s president, offered a similar apology at a 2005 meeting on improving health care and eliminating disparities, sponsored by the government’s Agency for Healthcare Research and Quality.

That came a year after the AMA joined the National Medical Association, a black doctors’ group, and other minority doctors’ groups in forming the Commission to End Health Care Disparities.

The commission has been working on raising awareness of health disparities, including disproportionate rates of many diseases among blacks and other minorities.

The new apology is a more formal acknowledgment of the AMA’s embarrassing past, and is also part of the AMA’s efforts to improve an image that in recent years has lost its luster. In many circles, the AMA is seen as a stodgy trade group focused on doctors’ rather than patients’ best interests.

Many black physicians applauded the AMA’s move.

“It is true that what the AMA did historically was awful,” the American Cancer Society’s chief medical officer, Dr. Otis Brawley, said. “There were AMA local chapters that actually had rules against black members well into the late 1960s, and policies that made blacks not feel comfortable well into the 1980s.”

Dr. Brawley, who is black, said he’s never been an AMA member, but that the apology “certainly makes me much more interested in working with them.”

A Chicago internist and member of the AMA and National Medical Association, Dr. Monica Peek, said the apology “creates an open and healthy dialogue for addressing these issues” that black doctors have long been aware of.

But she said AMA’s actions don’t lessen the need for a separate group representing black doctors.

Addressing health disparities hasn’t always been a part of AMA’s mission “but it’s something that has never been off of NMA’s radar,” Dr. Peek said.