Body weight

While not everyone who has osteoarthritis is overweight, being overweight is considered a great risk factor for the development and progression of osteoarthritis.

The knees, hips and back are called load bearing joints because they bear the physical load of the body during movement. Carrying excess weight creates an abnormal load for these joints and can overwhelm the joints capacity for self-repair.

The knees are particularly susceptible to excess weight. Research has shown that for each additional kilogram of body weight a person carries there is an extra 4 kilograms of force exerted through the knee joint with every step taken during the day.

Furthermore, joint cartilage responds to the increased loads by triggering mechanisms that result in the production of inflammatory molecules that can lead to the destruction of the joint.

Research also shows that obesity is a risk for osteoarthritis in joints that do not hold up any weight, for example your thumb. Fat storing cells release molecules that result in inflammation in the whole body, which can affect the health of the joints. These molecules have been found to increase both the risk of developing osteoarthritis, as well as its severity.

Lower body muscle strength

Good muscle strength is vital for a healthy joint. Muscles support joints from both above and below, and when muscle strength is diminished greater pressure is placed on the joint itself. Some joints have been shown to have a lower rate of osteoarthritis when supported well by stronger muscles.

In addition when your muscles are strong and working effectively they help stabilise the joints and improve balance, confidence and ability to be physically active.

Planned physical activity (eg. walking)

Individuals who experience knee buckling (‘giving way’) or sensations of knee instability generally experience greater fear of falling, poor balance confidence and activity limitations. All of which can contribute to the individual avoiding being physically active.

Many people with painful joints also tend to avoid being physically active for fear of making their pain worse.

When people avoid physical activities their muscle strength can deteriorate, which in turn can further limit their physical capabilities, increase pain when they are active, and cause greater knee instability – without intervention this cycle of deterioration can accelerate the progression of osteoarthritis.

Non-modifiable factors that can affect the development and progression of osteoarthritis include age, gender, genetics and ethnicity.