Women who regularly consume more than three alcoholic drinks a week for at least 10 years have about half the risk of developing the condition compared with non-drinkers.
A new study published on bmj.com says the risk was cut by 52pc in the drinkers.
The researchers say the findings add to a growing body of evidence that long-term moderate alcohol consumption is not harmful and may protect against chronic disease like rheumatoid arthritis.
They stress, however that the effect of higher doses of alcohol remains unknown.
Rheumatoid arthritis is a chronic inflammatory joint disorder that usually develops between the ages of 40 and 50.
About 1% of the world’s population is affected – women three times more often than men.
Some studies have shown that drinking alcohol is associated with a lower risk of rheumatoid arthritis, whereas others have found no association.
The relation between alcohol intake and rheumatoid arthritis remains controversial.
So a team of researchers based in Sweden set out to analyse this association among 34,141 Swedish women born between 1914 and 1948.
Participants were followed up for seven years and it was found that the rate of rheumatoid arthritis was less among those who drank more than four glasses of alcohol a week.
One standard glass was defined as about 500ml of beer or 150ml of wine or 50ml of spirits.
Further analyses made little difference to the results, supporting the theory that a moderate amount of alcohol may be a protective factor for rheumatoid arthritis. The authors suggest that this is most likely to be due to alcohol’s ability to lower the body’s immune response.
This is relevant because rheumatoid arthritis is an autoimmune disease – it causes the immune system, which usually fights infection, to attack the cells that line the joints.