RA risk with smoking is dose-dependant

Smoking is already established as a risk factor for the development of rheumatoid arthritis and Swedish researchers have now shown there is a dose-response relationship between the number of cigarettes smoked and risk of RA.

In a meta-analysis that included ten studies and 4552 cases of RA, researchers from the Karolinska Intitute in Stockholm found the risk of developing RA was 26% higher (RR= 1.26) in moderate smoker (one to ten pack-yeras) compared to never-smokers. However they also found that the risk of developing RA was doubled (RR = 1