It’s still not clear exactly what causes osteoarthritis. We do know it isn’t simply ‘wear and tear’ and that your risk of developing osteoarthritis depends on a number of factors:

Age

Osteoarthritis usually starts from the late 40s onwards. This may be due to bodily changes that come with ageing, such as weakening muscles, weight gain, and the body becoming less able to heal itself effectively.

Gender

For most joints, osteoarthritis is more common and more severe in women.

Obesity

Being overweight is an important factor in causing osteoarthritis, especially in weight-bearing joints such as the knee and the hip.

Joint injury

A major injury or operation on a joint may lead to osteoarthritis in that joint later in life. Normal activity and exercise don’t cause osteoarthritis, but very hard, repetitive activity or physically demanding jobs can increase your risk.

Joint abnormalities

If you were born with abnormalities or developed them in childhood, it can lead to earlier and more severe osteoarthritis than usual.

Genetic factors

The genes we inherit can affect the likelihood of getting osteoarthritis at the hand, knee or hip. Some very rare forms of osteoarthritis are linked to mutations of single genes that affect a protein called collagen. This can cause osteoarthritis to develop in many joints at an earlier age than usual.

Other types of joint disease

Sometimes osteoarthritis is a result of damage from a different kind of joint disease, such as rheumatoid arthritis or gout.

Two factors that may affect the symptoms of osteoarthritis, but aren’t a direct cause of it are the weather and diet:

• Weather - Many people with osteoarthritis find that changes in the weather make the pain worse, especially when the atmospheric pressure is falling – for example, just before it rains. Although the weather may affect the symptoms of your arthritis, it doesn’t cause it.
• Diet - Some people find that certain foods seem to increase or lessen their pain and other symptoms. However, your weight is more likely than any other specific dietary factors to affect your risk of developing osteoarthritis.