By: AP via Scripps News Group

"You're So Vain" singer Carly Simon has been diagnosed with Parkinson's disease and was recently treated for skin cancer, the singer shared in a statement provided to The Associated Press.

"So many people have written to me, kindly wondering about my relative silence, asking how I am and what I have been doing. The truth is, I've been learning how to live with Parkinson's disease," Simon's statement on Monday read.

The singer, 83, had been experiencing arthritis in one of her hips and both her knees, resulting in replacement surgeries for those three joints. But her mobility continued to decline. At times, she said, she could not walk without "considerable help."

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"My family and I knew that something more was going on. After an extensive evaluation at the Mayo Clinic, I was diagnosed with Parkinson's," she said.

"It has taken me some time to understand the diagnosis, to adjust to it, and to decide how much I wanted to say about it publicly," she explained. "Parkinson's is different for everyone, and it can be unpredictable. Some days I'm so tired I can't get the day moving at all. On others, it gives me a little more room to move, think, work, and feel like myself."

Parkinson's is a neurologic disease that robs people of control over their movements. It typically starts with tremors and is characterized by slow movement, a shuffling gait, stiff limbs, balance problems and slurred speech.

About 1 million Americans are living with Parkinson's, and 10 million people worldwide, the Parkinson's Foundation estimates. It usually appears after age 60, though it sometimes develops before age 50.

The exact cause isn't known, but Parkinson's develops when cells that produce one of the brain's chemical messengers — dopamine — begin to deteriorate and die.

There is no cure, but there are treatments including medications that affect dopamine levels and a surgically implanted tremor-blocking device. Patients also can benefit from physical and occupational therapy.

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"I began treatment, including taking medication to help with stiffness and other symptoms," Simon said. "There is no tidy or predictable schedule to the illness. It does not consult my calendar before deciding what kind of day I am going to have."

She also shared that she was treated for basal cell carcinoma, a common form of skin cancer, on her face at the same time. She had surgery, and the cancer was removed, "but the surgery affected my appearance and made me more self-conscious about being seen in public," she said.

She said music has been a salve, and on Aug. 14, she will release "Comes in Waves," her first album of original songs since 2008.

"Working on the music gave shape to days that did not always have much shape. It gave me somewhere to go without having to leave the room," she continued. "It reminded me that illness can change your life without becoming the whole of your life."