People are putting themselves at risk of an early death by failing to act on the early signs of rheumatoid arthritis, a doctor warned today.

The crippling condition causes swelling and pain in the joints, but these symptoms are often dismissed as an inevitable consequence of ageing or too minor to trouble a GP with.

A study into patients diagnosed with rheumatoid arthritis found that on average, they went untreated for more than six months, and that most of this delay was due to people failing to raise the issue with their GP.

Dr Karim Raza, a consultant rheumatologist at Sandwell and West Birmingham NHS Hospitals, said that acting on the first signs of rhemuatoid arthritis was crucial because it can be treated successfully if caught within three months.

"The condition does not just affect the joints. People with rheumatoid arthritis typically die 10 years younger from premature heart disease," Dr Raza said.

Rheumatoid arthritis is an immune disorder that targets the joints, but also damages other parts of the body. The condition affects 350,000 people in Britain and usually appears between the ages of 30 and 50. Three times as many women are affected as men.

"The data suggests that if you intervene within the first three months you can very rapidly slow progression of the disease and in some cases halt it," Dr Raza said. "There is also a suggestion that if you intervene aggressively you might in a small proportion of people actually switch off the disease."

The disease begins with swelling across the knuckles and possibly the toe joints. The joints become stiff and painful to move and eventually become badly swollen. The condition is different from other forms of arthritis in that the stiffness and pain is worst in the morning and eases through the day.

"We need to raise awareness of the seriousness of the condition among the general public so they get quick access to the care they need, and which can make such a difference to the outcome of their disease," Raza said.