December 15, 2010

Smokers at Risk of Rheumatoid Arthritis

(Ivanhoe Newswire) -- On top of a myriad of other risks, smokers have yet another reason to kick the habit.  A recent study published in the Annals of the Rheumatic Diseases identified smoking in more than a third of the cases of rheumatoid arthritis.  Over half of the victims who were genetically predisposed to the disease were also smokers.

The study looked at 1,200 rheumatoid arthritis patients and a control group of 871 disease-free people selected for their matching ages (between 18 and 70) and gender.  Each participant was quizzed about their smoking activity, and then organized into one of three groups based on the length of his or her smoking history.

Next, the researchers took blood samples to both identify any genetic predispositions to rheumatoid arthritis and looked at the victims' antibody levels to measure the severity of their disease.

61% of the rheumatoid arthritis-suffering participants tested positive for anticitrullinated protein/peptide antibody (ACPA) which indicates the presence of the most severe (and most common) form of the disease.  The heaviest smokers, who went through 20 cigarettes per day for at least 20 years, were over two and a half times as likely to be ACPA-positive.  Ex-smokers were at a decreased risk, depending on how long they had been tobacco-free and how heavily they smoked.

55% of those who were found to be genetically predisposed to the disease, and also tested positive for ACPA, were smokers.  The heaviest smokers were at the greatest risk.

Smokers constituted one in five cases of rheumatoid arthritis, and 35% of all ACPA-positive cases.  The researchers claimed that these percentages were similar to those found in the risk factor of coronary heart disease.

The researchers make it clear that other environmental factors such as air pollution and hormonal factors also put people at risk of rheumatoid arthritis, but assert that their findings are a crucial warning for smokers who have a family history of the disease.

SOURCE:  British Medical Journal, December 2010