Smoking is linked with the production of rheumatoid factor.
A long-term smoking habit of 20 or more cigarettes a day leaves people at a higher than average risk of developing rheumatoid arthritis, say researchers. People who have smoked heavily for 40-50 years are 13 times more likely to develop the condition. The study, carried out at St. Helens and Whiston Hospitals, Merseyside, found over half of those with rheumatoid arthritis had no family history of the disease. The team looked at 239 patients with rheumatoid arthritis, and 239 healthy people.