New research shows that the number of cigarettes smoked in a day and the number of years of smoking both increase risk of rheumatoid arthritis (RA) in elderly women.

This risk goes down after they give up smoking but, compared to women who have never smoked, it is still high up to 15 years later.

RA is an autoimmune disease that manifests as a chronic inflammatory disorder affecting multiple tissues and organs. It mainly attacks flexible joints and is a disabling and painful condition that can lead to a significant loss of functioning and mobility if not properly treated.

RA destroys cartilage and causes joint fusion. Although its underlying causes are still unknown to health experts - based on a clinical diagnosis based on symptoms, physical exam, X-rays and lab tests, it is clearly an autoimmune disease.

In the present study, researchers from the Karolinska Institutet and Karolinska University Hospital in Sweden analyzed data from the Swedish Mammography Cohort with 34,000 women aged between 54 and 89 - of these, 219 women had RA.

According to this study, even light smoking means a greater risk of RA - while smoking 1-7 cigarettes every day more than doubled this risk. When women who had never smoked were compared to those who smoked for up to 25 years, RA risk was also found to rise with smoking duration.

Stopping smoking decreased chances of getting RA, especially over time. For instance, 15 years after giving up smoking RA risk had gone down by a third. However, compared to women who had never smoked, this risk remained significantly high even up to 15 years later.

Stopping smoking is important for many health reasons. Higher risk of developing RA, even many years after giving up smoking, is one more strong reason to stop smoking as soon as possible - and important enough to persuade women not to start smoking at all.