BOSTON -- New research suggests rheumatoid arthritis is rising in women, but not men.

Rheumatoid Arthritis Up In Women?

"I've been dancing since I was 3," said Jenna McMahon, a patient at Boston's Brigham & Women's Hospital.

Being a dancer all her life, McMahon was devastated when she lost the ability to walk on her own four years ago.

"During my pregnancy, I actually ended up in a wheelchair for a bit, because I couldn't move my hip joints," she said.

When her son was born, Jenna was diagnosed with rheumatoid arthritis, a chronic illness that is triggered by the immune system.

"It started with my arm. I wouldn't be able to move past a certain point. It would go to my knee, and it would hit different points of my body," McMahon said. "When my son was born, I wasn't able to button his little pajamas. I couldn't walk up the stairs."

Rheumatoid arthritis most often affects small joints in the hands and feet, causing pain, stiffness, swelling and limitation of movement. According to research at The Mayo Clinic in Rochester, Minn., RA appears to be increasing among women, but not in men. The lead researcher on the study suspects environmental factors or hormones for the increase. It's research that McMahon would like to have investigated further.

"A year after I was diagnosed, my mother was diagnosed with rheumatoid arthritis. And we live in the same house," McMahon said.

Four years after her diagnosis, McMahon is taking medication to relieve the pain. It's allowing her to do what she loves.

"I couldn't be without dancing. Dancing is what keeps me happy," she said.