The actor said he is less steady on his feet and has broken several bones. But he says gratitude has helped him remain optimistic.

In a revealing interview, the actor Michael J. Fox spoke about his own mortality and the challenges of living with Parkinson’s disease for more than 30 years, including his experiences with falling and breaking bones.

The interview, with Jane Pauley of “CBS Sunday Morning,” was to promote his new documentary “Still,” to be released May 12.

“It’s banging on the door,” Fox, 61, said of the disease. “It’s getting harder. It’s getting tougher. Every day gets tougher, but that’s the way it is. Who do I see about that?”

Fox, an Emmy and Golden Globe Award-winning actor, was diagnosed with Parkinson’s in 1991 at age 29. He had been filming the movie “Doc Hollywood,” and sought medical advice about a tremor he had developed in his pinkie finger. He didn’t publicly disclose that he had the disease for several years.

Parkinson’s disease is a progressive and debilitating disorder that causes uncontrollable jerks and twists, shaking, slurred speech, and difficulty with balance and coordination, among other things. The disease, which progresses as nerve cells in the brain weaken or die, is more common in men, although researchers don’t know why. The actor Richard Lewis, 75, recently announced he has Parkinson’s.

A clip from the documentary shows Fox stumbling and falling hard on a New York City sidewalk. A passerby checked on him. His response: “You knocked me off my feet.”

Fox said he has had surgery for a benign tumor on his spine, which “messed up my walking,” and he is less steady on his feet.

“Now I break stuff,” he said. “This arm and this arm, this elbow. I broke my face. I broke my hand from falling.”

Falling, he noted is “a big killer” for people with Parkinson’s. He also noted that aspirating food and pneumonia are risks.

“All these subtle ways it gets you,” he said. “You don’t die from Parkinson’s. You die with Parkinson’s. I’m not gonna be 80.”

In 2000, Fox launched the Michael J. Fox Foundation for Parkinson’s Research, which has supported some of the most ambitious research in the field. In April, researchers announced a major breakthrough, identifying forms of a protein and a testing method that can be used to diagnose Parkinson’s much earlier and reduce the numbers of people who are wrongly diagnosed with the disease.

The research stems from the Fox foundation’s Parkinson’s Progression Markers Initiative, which for more than a decade has followed more than 1,100 volunteers with and without the disease.

“It changes everything,” Fox said of the research. “With where we are right now, in five years we will be able to tell if they have it, be able to tell if they’re going to get it, we’ll know how to treat it.”

Pauley, who interviewed Fox early in his career, noted that the disease has taken a visible toll. “Every time I see you, I can see it’s taken a little bit more of something,” she told him.

“For 30 years,” he responded. “There’s not many of us that have this disease for 30 years. It sucks. It sucks having Parkinson’s. For some families, it’s a nightmare. It’s a living hell. You have to deal with realities that are beyond most people’s understanding.”

Despite the challenges of living with Parkinson’s, Fox noted that he has had advantages others haven’t.

“I have a certain set of skills that allow me to deal with this stuff,” he said. “With gratitude, optimism is sustainable. If you find something to be grateful for, then you can find something to look forward to and you carry on.”