Why does osteoarthritis happen in younger people?

Osteoarthritis is often thought of as a disease of ageing. However, younger people can also be struck by this degenerative joint condition. Expert rheumatologist Dr Taher Mahmud explains.

How common is osteoarthritis in younger people? How early can the first symptoms appear?

Osteoarthritis is rare under 40 years old and rarely requires surgery in the under-50s, but there are a few factors worth knowing about related to ‘premature osteoarthritis’. It is also important to know that inflammatory arthritis is different and can affect the young more commonly.

When we are talking about osteoarthritis, we usually mean the wearing out of the slippery, shiny, bearing surface of the joint – the articular cartilage – leaving bare bone rubbing on bare bone. This then causes inflammation with pain, stiffness and, later, deformity. Think of it like the tread on a car tyre wearing out until finally the tyre is bald and needs to be replaced.

What kind of sports can lead to osteoarthritis?

Any sport that causes an injury to the joint can bring on early arthritis. This injury may be in the form of a heavy blow to the articular cartilage in the joint, causing it to die and peel off the bone; it may be damage to a ligament that keeps the joint stable, or damage to a cushioning fibrocartilage (such as the meniscus in the knee), meaning that the articular cartilage wears out before its time. 

Common causes of these sorts of things are twisting and collision during sports such as football, rugby, netball and skiing. The impact of running with bad form, or if overweight can do it too.

Is there a genetic factor?

Yes, there is certainly a trend for early-onset arthritis to run in families, and there are a number of genes identified so far that play a part. It is not a simple relationship like colour blindness, but a polygenic mechanism.

Can it be related to your anatomy (e.g. height)?

Anatomical factors within joint shapes do play a role (for example, the ball of the hip joint not being perfectly round, or the kneecap being higher than average). Height per se is not a factor, but weight and body mass index (BMI) certainly are, and being overweight can be disastrous.

Do other lifestyle factors make a difference?

Smoking is bad news for just about everything, including osteoarthritis. Poor sleep is increasingly being investigated too. Poor diet leading to increased weight is not at all helpful.

On the sports issue, I am very much a believer in 'finding your sport'. Not every person is built for every sport, but almost everyone can do something. So if you are super flexible it may be dance, swimming or gymnastics, but if you are tight and springy then sprinting and jumping sports will be better. Finding your sport and enjoying it in moderation is a good way to keep healthy and keep arthritis at bay.

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