A few cigarettes a day increases risk of RA

A new study, published in the open access journal Arthritis Research & Therapy, shows that smoking just a few cigarettes a day more than doubled the risk of rheumatoid arthritis (RA). To give up smoking decreases the risk, but compared to people who have never smoked this risk is still elevated 15 years after giving up.

Researchers from Karolinska Institutet and Karolinska University Hospital analysed data from the Swedish Mammography Cohort, which included 34,000 women aged between 54 and 89. Among these women 219 had RA.

The link between smoking and rheumatoid arthritis is known from previous research. Results of the currect study showed that even light smoking is associated with an increased risk of RA; smoking 1 to 7 cigarettes a day more than doubled this risk. When the team compared people who had never smoked, to women who had smoked for up to 25 years, they found that the risk also increased with length of smoking.

Stopping smoking did decrease chances of developing RA, with the risk continuing to decrease over time. Fifteen years after giving up the risk of RA had decreased by a third. However, compared to people who had never smoked this risk remained significantly higher still 15 years after giving up.

"Stopping smoking is important for many health reasons, including the increased risk of RA for smokers", says Daniela Di Giuseppe, Doctoral Student at the Institute of Environmental Medicine at Karolinska Institutet, who led the study. "But the clearly increased risk of developing RA even many years after giving up smoking is another reason to stop as soon as possible, and also highlight the importance of persuading people not to start at all."

The study was funded by grants from the Swedish Research Council and Karolinska Institutet. A major part of this news article has originally been published as a press release from BioMed Central.