Smoking increases rheumatoid arthritis risk

Smoking is a risk factor for rheumatoid arthritis (RA) and the effect is especially strong in men and heavy smokers, a new analysis of 16 studies confirms.

Research over the past two decades has linked smoking to rheumatoid arthritis (RA), especially in men. But findings on smoking and RA in women have been inconsistent. The researchers conducted the first systematic analysis of research on RA risk and smoking, looking at 16 studies in all.

It was noted that men who were current smokers were at nearly double the risk of RA and the effect was roughly the same in ever- and past smokers. When the researchers looked at rheumatoid factor (RF)-positive RA, they found male smokers were at nearly four-fold risk of the disease, while risk was tripled in ever-smokers and about 2.5 times greater for past smokers. Smoking also increased RA risk in women, but to a lesser degree. Female current, ever- and ex-smokers had a 1.2 to 1.3 times greater likelihood of developing RA, whether or not they were RF-positive.

The men who had logged at least 20 pack years - meaning they had smoked at least 20 cigarettes a day for 20 years - were 2.3 times more likely to develop RA, while for women risk was increased 1.75-fold.

The findings indicate that any type of smoking constitutes a significant risk factor for the development of RA. The researchers recommend cessation of smoking for current smokers, especially heavy smokers to prevent or reduce the risk of developing RA.