By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - Rheumatoid arthritis is the most common form of inflammatory arthritis. One percent of people will get rheumatoid arthritis in their lifetime.

Although it can start ant any age, it usually peaks between 30 and 50 years of age and the toll can be high.

Thirty five percent of people with rheumatoid arthritis can have a disability after ten years. We know that it runs in families. When there is swelling in one joint it is not as likely to be rheumatoid arthritis but when multiple joints are affected the risk is greater.

There are blood tests, which help us make the diagnosis. It is important that we diagnose it early in the course because the earlier the treatment begins the better the long term prognosis. This is why it is important to visit the doctor if you have joint pain like this.

The good news is that treatment continues to improve.