Arthritis is not a single disease, but an umbrella term for more than 100 conditions that affect the joints of the body. The most common types of arthritis are osteoarthritis and rheumatoid arthritis.

• Osteoarthritis: This is the most common type of arthritis and is caused by the wear and tear of the joint over time or because of overuse. It involves the breakdown of cartilage, the hard, slick coating on the ends of bones where they form a joint. This wear and tear can occur over many years, or it can be hastened by a joint injury or infection.

• Rheumatoid arthritis: This is an inflammatory disease of the joint linings. The inflammation may affect all of the joints. It can also affect organs such as the heart or lungs. In rheumatoid arthritis, the bodys immune system attacks the lining of the joint capsule, a tough membrane that encloses all the joint parts.

Other forms of arthritis or related disorders include gout, lupus, and scleroderma. Reactive arthritis is caused by an infection in the body. Some forms of arthritis can be linked to genes. Environmental factors that may contribute to the development of osteoarthritis include obesity, activities that involve repetitive movements of a particular joint, and previous damage to a joint, such as from a sports injury.

In summary, the causes of arthritis depend on the type of arthritis. Osteoarthritis is caused by the wear and tear of the joint over time or because of overuse, while rheumatoid arthritis, lupus, and scleroderma are caused by the body’s immune system attacking the body’s own tissues. Gout is caused by the buildup of crystals in the joints, and some forms of arthritis can be linked to genes. Environmental factors such as obesity, repetitive movements of a particular joint, and previous damage to a joint can also contribute to the development of arthritis.