Heavy snorers at greater risk of rheumatoid arthritis

People who snore heavily are at an increased risk of developing rheumatoid arthritis which is believe to affects over 21 million people worldwide, a new study has claimed.

Researchers from the Taipei Medical University in Taiwan found patients diagnosed with the snoring-related condition, called sleep apnoea, were nearly twice as likely to suffer the joint-damaging disease.

The finding, published in the journal Sleep Medicine, is something of a surprise as rheumatoid arthritis is thought to be triggered when something goes wrong with the immune system.

The new study also found a similar increase in the risk of other so-called autoimmune disorders, where the body's defences start to attack healthy tissues. The scientists said they believe the explanation lies in the fact that chronic sleep apnoea can lead to inflammation in blood vessels throughout the body, which may act as a catalyst for arthritis, the Daily Mail reported.

In the study, the researchers compared 1,411 sleep apnoea patients to a 7,000-strong group of healthy adults for over five years, monitoring how many of them went on to develop rheumatoid arthritis, ankylosing spondylitis and systemic lupus erythematous. All these conditions arise when the immune system goes haywire and causes swollen, painful joints and flu-like symptoms.

The results showed the snoring-affected group were 91 per cent more likely to develop one of the three conditions. However, the researchers stressed that the absolute risk of falling ill was still small. Out of the snoring patients, only 2.91 per cent experienced arthritis-related problems.

"Our study is the first to investigate the association between sleep apnoea and the development of autoimmune diseases," the researchers wrote. "We think this may have gone unnoticed in clinical settings because these cases are relatively rare and may not be reported. But the potential link between the two conditions should not be overlooked.

"Among the diseases we studied, rheumatoid arthritis had the highest risk of developing in sleep apnoea patients." When people with sleep apnoea sleep, their airway muscles relax disrupts breathing and triggers the sound of snoring. This normally wakes them up causing sleep disturbance which can result in inflammation in blood vessels.