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10 Basic Facts Most People Don't Know About Osteoarthritis

Do You Know These Osteoarthritis Facts?


Updated April 08, 2010

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

1) Osteoarthritis is the most common type of arthritis.

Osteoarthritis affects 13.9% of adults age 25 years and older and 33.6% of people 65 years and older. The CDC estimates that 26.9 million American adults have osteoarthritis (based on the most recent data from 2005).

2) There are two major classifications of osteoarthritis - primary (idiopathic) or secondary.

Primary osteoarthritis is also referred to as idiopathic osteoarthritis because there is no known underlying or predisposing cause. Secondary osteoarthritis develops as a result of another medical condition or a trauma at the joint (for example, a sports injury).

3) The knees and hips are the joints most commonly affected by osteoarthritis.

Data from the Framingham OA Study revealed that symptomatic knee osteoarthritis affects 6.1% of all adults over age 30 and 9.5% of all adults between 63-93 years old. Symptomatic hip osteoarthritis affects 4.4% of adults 55 years and older.

4) Women have higher rates of osteoarthritis than men -- especially after age 50.

According to the CDC, men have a 45% lower risk of knee osteoarthritis and 36% lower risk of hip osteoarthritis than women.

5) Osteoarthritis accounts for approximately 6% of arthritis-related deaths.

About 500 deaths per year are attributed to osteoarthritis. The number has risen in the last 10 years. It should be noted that the number may underestimate the true contribution of osteoarthritis to mortality and is hard to compare. For example, death from NSAID use is not counted.

6) Osteoarthritis of the knee is one of the five leading causes of disability among non-institutionalized adults.

About 80% of osteoarthritis patients have some limited range of motion. About 25% cannot perform activities of daily living. Statistics from 1999 show that people with knee osteoarthritis missed more than 13 days of work.

7) Modifiable risk factors can help manage osteoarthritis.

Managing your weight, changing jobs to relieve repetitive stress, avoiding joint injury, and participating in regular physical activity are important actions that serve to modify risk factors for osteoarthritis.

8) Genetics may play a significant role in osteoarthritis.

Researchers recognize that about 20-35% of knee osteoarthritis and about 50% of hip and hand osteoarthritis may be determined by genetics.

9) Seventy percent of people over 70 years old have x-ray evidence of osteoarthritis.

While 70% of people over 70 have x-ray evidence of osteoarthritis, only half of the group with x-ray evidence develop symptoms.

10) Even though osteoarthritis isn't considered as crippling as rheumatoid arthritis, pain and physical limitations make osteoarthritis a significant disease.

Approximately 40% of adults diagnosed with knee osteoarthritis report that their health is either poor or fair.


Osteoarthritis. Centers for Disease Control and Prevention. February 4, 2010.

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