Being fat as a child increases the risk of developing arthritis in the hips and knees, a study has found.
Adult obesity is known to contribute to and worsen arthritis, but new research suggests being obese as a child also increases the likelihood of arthritis in later life.
A person’s weight as a child actually affects their chance of developing hip arthritis more than their weight in adulthood does, the research shows.
The research comes after figures revealed a third of children leaving primary school are overweight in the UK, with 22,000 of them classed as obese.
Obesity is being called a global health crisis and is known to have serious consequences like cancer and heart disease.
Scientists who carried out the study say its results should add more urgency to efforts to get people to slim down.
Being obese in childhood increases a person’s risk of developing arthritis in their hips or knees in later life, research shows
The study, by the European League Against Rheumatism (EULAR), found links between obesity in children and osteoarthritis – the most common form of the condition and the one usually associated with old people.
Osteoarthritis causes joint pain, stiffness, swelling and tenderness and can get worse over time.
It is caused by cartilage in the joint breaking down, reducing the protection between bones, commonly in the knees, hips and hands.
Being overweight can make this worse because it puts extra strain on the joints, and the new research suggests this could begin long before the condition is diagnosed.
‘This data should add urgency to tackling obesity’
Johannes W. Bijlsma, president of the EULAR said: ‘Obesity in both childhood and adulthood is an important public health issue.
‘These data showing a causal relationship with osteoarthritis should add further impetus to tackle the issue of obesity and reduce related disability.’
The study was based on people’s Body Mass Index (BMI) measurements, which compare someone’s height and weight to determine whether they are overweight.
People with a BMI of over 30 are considered to be obese, unless they are extremely muscular, and a healthy range is 18.5 to 24.9.
Arthritis risk increases by half a percentage per extra BMI point
EULAR’s research found that for each extra BMI point in an obese child their risk of being diagnosed with knee or hip arthritis as an adult increases by 0.6 per cent, which scientists say is significant.
In obese adults, each extra BMI point raises their risk of knee arthritis rises by 1.3 per cent and hip arthritis by 0.4 per cent.
There is no link between obesity and arthritis in the hands, according to the research.
Study author Professor Daniel Prieto-Alhambra added: ‘Our results suggest the effect of adult BMI seems to be stronger on knees, whilst childhood BMI might impact both knee and hip osteoarthritis risk similarly.
‘Interestingly our findings contradict previous studies that found an association between obesity and hand osteoarthritis.’
Extra bodyweight puts extra strain on the joints
Obesity can make it more likely for someone to develop arthritis because the heavier they are, the more work weight-bearing joints like the hips and knees have to do to support their bodyweight.
Then once a person already has arthritis, the strain puts stress on the already-damaged joint.
According to the Arthritis Foundation, every pound of excess bodyweight exerts about four pounds (1.8kg) of extra pressure on the knees.
So a person who is 10lbs (4.5kg) overweight has 40lbs (18kg) of extra pressure on their knees.
If a person is seven stone (44kg) overweight – for example, someone who is 5’9 and 15st7lbs – that is 28st5lbs (181kg) of extra pressure on their knees.