One of the dreaded aspects of growing older is developing arthritis, an often debilitating disease, causing painful inflammation of joints.

Although no one can prevent aging, people can reduce the risk of developing arthritis by losing weight, eating the right foods and exercising regularly, doctors say.

Osteoarthritis, the most common form, develops as cartilage that cushions the joints wears away, leaving the ends of the bones rubbing against each other.

Osteoarthritis commonly begins to show up between the ages of 40 and 60, so most baby boomers are “right smack in the target range,” said Bill Roberts, an associate professor of family medicine at the University of Minnesota and president-elect of the American College of Sports Medicine.

Extra weight on cartilage brings extra risk of the joint disease. “The simple explanation is, you’re putting more biomechanical stress on the joints,” said Kevin Fontaine, an assistant professor of rheumatology at the Johns Hopkins School of Medicine.

Fontaine and his colleagues looked at survey data from the Centers for Disease Control and Prevention, and concluded that the odds of joint pain went up as weight did.

According to the study, people ages 60 and older had a 12 percent likelihood of joint pain if they were underweight but a 60 percent chance if they were obese.

Although the CDC survey did not ask whether the pain came from arthritis, Fontaine believes it did because the people polled were in the right age range.

“Losing weight can reduce the risk of developing arthritis,” said Dr. David Pisetsky, director of the Duke University Arthritis Center and a medical adviser to the Arthritis Foundation.

“There is good evidence that people who are close to their ideal weight are going to have fewer problems,” he added.

Eating healthy benefits the growth of cartilage. Cartilage gets nutrients from fluids in the joint, and the nutrients can then be squeezed into the tissue by movement.

That’s why eating right and exercising are so important in staving off the development of arthritis.

The muscles that protect the knee, one of the most common sites for osteoarthritis, act as shock absorbers. Strengthening them relieves pressure on the joint, said Dr. Nicholas DiNubile, a clinical associate professor of orthopedic surgery at the University of Pennsylvania.

Researchers can’t yet tell how much activity is the right amount to reduce the risk of developing arthritis, Pisetsky said. But, they do know that at least one half hour a day of moderate activity such as brisk walking is good for overall health.

If people want to do more, such as possibly walking an hour and adding some weight training, they might get more benefit, but the research can’t prove it, Pisetsky said.

People who already have arthritis can still make a difference in the amount of pain they suffer from, just by losing weight and keeping their joints active.

Exercises that pound joints, such as running, are off-limits, but gliding movements are fine, DiNubile said. He recommends water aerobics, designed specifically for people with arthritis, as well as exercise bikes and elliptical trainers.