As for what’s behind the increased activity limitations, the CDC believes it’s a combination of two things – age and obesity.

“We expected to see some of this increase because of the aging of the population,” Dr. Hootman explains. “But this is more than we expected in activity limitation and that’s probably, although we can’t directly link it, that’s probably related to the increase in high prevalence of obesity.”

The CDC’s report says about 1 in 3 people who are obese have arthritis. This is almost double prevalence of arthritis in normal-weight people.

“The link that obesity can worsen your arthritis and cause arthritis is a total and utter surprise to people,” Dr. White says.“They don’t know that. They think arthritis is just an old person’s disease. They don’t know there is something you can do about it.”

Studies have shown that obesity dramatically increases the risk for arthritis, though researchers aren’t sure why. Some evidence has pointed to the idea that force of carrying extra weight damages joints, while other studies have suggested that inflammatory chemicals released by fatty tissue may be to blame.

Whatever the mechanism, experts say the bottom line is that arthritis is not an inevitable consequence of aging.

Dr. Hootman says people need to understand that activity limitations can be prevented or improved through weight loss, physical activity, and what’s called self management education – where people are taught to develop goals and learn ways to manage their arthritis symptoms day to day.

“Those things all improve pain and function and that should translate to reduced activity limitations,” Dr. Hootman says.

Dr. White says these new numbers remind the public health community there’s still much work to be done.

“We can’t change age,” she explains. “But can we have them age in a more healthy manner? You bet.”

“What they don’t know is there are ways to be active. Their assumption is moving hurts me; I shouldn’t do something that hurts me. So we have a huge job to get people to understand that actually, movement helps,” she continues. “I think we have to work even harder to get people moving and doing the kind of activities that are going to make their life better.”