The overall impact of arthritis might also depend on whether other health problems are present, says Furner. Researchers found that people with arthritis were more likely to rate their health as poor or fair if they were obese, or had diabetes or high blood pressure, and people with arthritis who were physically active were 50 percent less likely to rate their health as fair or poor than those who said they didn't get much exercise. This suggests that people with arthritis might be able to improve their quality of life by getting exercise and maintaining a healthy weight, for example. "These are modifiable risk factors, and that's an encouraging note," says Furner.

The authors also found that people with arthritis who admitted to frequent heavy drinking were less likely than non-drinkers to rate their health as fair or poor, and reported fewer physically unhealthy days. This doesn't suggest that such drinking is healthy, however: In the later years of the survey, people answered questions about emotional support, and Furner and her colleagues saw higher levels among people with arthritis who drank more alcohol. Emotional support, specifically in the form of a strong social network, may help protect against the negative effects of a chronic condition, she says.  

Financial considerations also appeared to play a role. People with arthritis who were out of work, unable to work or who said cost was a barrier to proper care were more likely to report poor or fair health than those who were employed and could afford appropriate health care.

The results are interesting, but more research is needed to elucidate cause and effect in some cases, says Edward Yelin, PhD, professor of medicine at the University of California, San Francisco. For example, he adds, "People may stay physically active because they don't have arthritis or don't have it as severely – or are people who are more active less likely to get it?"

Some factors associated with quality of life in arthritis make particular sense, such as the added burden of other diseases like diabetes, notes Patience White, MD, a professor of Medicine and Pediatrics at George Washington University School of Medicine. "The more chronic illness you have, the tougher it is for you to do anything," she says.

Overall, the study "has some lessons for all of us to learn in how people with arthritis can improve their quality of life," says Dr. White, who is also vice president of public health at the Arthritis Foundation.

This large study helps provide very "reliable estimates" of some of the challenges people with arthritis face, says Yelin. "There's nothing all that surprising about it. But it does give us some notion, with this sample from all 50 states, of how severe these impacts can be."