Bones and joints become vulnerable to wear and tear as we age, and doctors can determine the amount of bone loss with a bone mineral density (BMD) test. Treatments for aging bones and joints range from pain relievers and physical therapy to joint replacement.

More than 52 million adults, many of them over 65, live with arthritis. About half of them are limited in their activities. Arthritis is a degenerative condition in which the joints—the cushioning surfaces between bones—wear away. Typical arthritis symptoms include pain, stiffness, swelling, and reduced range of motion.

Arthritis comes in many forms, including degenerative osteoarthritis, rheumatoid arthritis (an autoimmune disease), and psoriatic arthritis. In psoriatic arthritis, not only do the joints swell up, but red, scaly patches called plaques also form on the skin. Gout is another type of arthritis that’s caused by a buildup of uric acid in the blood. The excess uric acid forms into crystals that congregate in the joints—most often in the big toe—causing pain and swelling. A number of medications are available to treat arthritis pain and inflammation.

With time, bones become weaker, more brittle, and could fracture. The early stage of bone loss is called osteopenia, and it affects about half of Americans over age 50. Results of a bone mineral density (BMD) test are expressed as a T-score, which is based on a comparison with the bones of a healthy 30-year old. People with normal bone density have a T-score that is within 1 standard deviation (SD) of a 30-year old’s score. A score 1 to 2.5 SD below a young adult’s (-1 to -2.5 SD) is considered low bone mass, or osteopenia. Osteoporosis is diagnosed in anyone with a score of -2.5 SD or lower. People with osteoporosis need to take medicines such as bisphosphonates to strengthen their bones and prevent fractures.