Long-term smoking cessation in women was associated with a lower risk of rheumatoid arthritis (RA) compared to those who had recently quit, a new study has shown.

Rheumatoid arthritis is a chronic inflammatory disorder affecting many joints, including those in the hands and feet. The study showed that the risk of seropositive RA - when patients have antibodies in their blood that help identify the disease - was reduced by 37 per cent for those who sustained smoking cessation for 30 or more years compared with those who recently quit smoking.

"Our study is one of the first to show that a behaviour change of prolonged smoking cessation may actually delay or even prevent the onset of seropositive RA, suggesting lifestyle changes may modify risk for development of a systemic rheumatic disease," said Jeffrey Sparks from the Brigham and Women's Hospital in the US.

Patients who have seropositive RA tend to have a more severe disease course with more joint deformities, disability, and inflammation outside of the joints. On the other hand, there was no association of smoking with seronegative RA - when patients have no antibodies in their blood that help identify the disease - suggesting a different pathogenesis than seropositive RA, said the study, published in the journal, Arthritis Care & Research.

Smoking has been known to be a major risk factor for various diseases including heart disease and cancer. According to the World Health Organisation, rheumatoid arthritis tends to strike during the most productive years of adulthood, between the ages of 20 and 40 and is more common among women. For the study, the researchers included 230,732 women.