A study has begun into whether Vitamin D supplements can slow down a condition which leads to the degeneration and inflammation of joints.
Norfolk and Norwich University Hospital is one of five centres which hopes to study 800 people with the early stages of knee osteoarthritis.
There is no cure for the condition but studies suggest diets rich in Vitamin D can help slow down its progress.
It is hoped the trial will provide conclusive evidence of the benefits.
As well as the Norfolk and Norwich Hospital the research is being carried out at Hope Hospital in Manchester, Royal Victoria Infirmary in Newcastle and the Royal National Orthopaedic Hospital in London.
The study, which costs just under £750,000, involves participants being given either vitamin D pills or a placebo for three years.
Researchers are looking for volunteers aged over 50 and who have the early stages of knee osteoarthritis to take part in the study.
Osteoarthritis is the commonest form of arthritis and can cause disability in the elderly.