The Scandinavian researchers base their findings on more than 2750 people taking part in two separate studies, which assessed environmental and genetic risk factors for rheumatoid arthritis.

Over half the participants (1650) had the disease and had been matched for age, sex, and residential locality with randomly selected members of the general public.

All participants were quizzed about their lifestyle, including how much they smoked and drank. And blood samples were taken to check for genetic risk factors.

The results showed that drinking alcohol was associated with a significantly lower risk of developing rheumatoid arthritis. And the more alcohol was consumed, the lower the risk of rheumatoid arthritis.

Among those who drank regularly, the quarter with the highest consumption were up to 50% less likely to develop the disease compared with the half who drank the least.

The effect was the same for both men and women.

Among those with antibodies to a specific group of proteins involved in the development of the disease, alcohol cut the risk most in smokers with genetic risk factors for rheumatoid arthritis.

Smoking is known to be a major environmental risk factor for developing rheumatoid arthritis, and this risk is further increased in those who carry these genetic variants.

The authors conclude that their research reinforces the importance of lifestyle factors in the development of the disease, and that giving up smoking remains the single most important preventive measure.

They point to recent experimental research by other authors, which showed that alcohol protected against the development and severity of rheumatoid arthritis, although it is not clear exactly how it does this.

And they draw parallels with the links between moderate alcohol consumption and a reduced risk of other inflammatory processes, such as cardiovascular disease.

Source: British Medical Journal