Smoking is Major Risk Factor for Rheumatoid Arthritis
If you want to avoid living with debilitating rheumatoid arthritis, put out that cigarette. A new Swedish study reports that smoking is a major risk factor for the disease and is associated with the amount of smoking and genotype.
Smoking is a preventable risk factor
The main risk factors for rheumatoid arthritis are generally listed as sex (women are more likely to develop the disease than men are, and there is evidence it is increasing among women), age (usually develops between ages 40 and 60), family history of the disease (you can also inherit a predisposition), and smoking. A recent study from Boston University School of Public Health suggests a vitamin D deficiency may have a role in the disease as well.
Based on previous research that showed smoking and genetic risk factors work together to increase a person’s risk of developing rheumatoid arthritis, investigators at the Karolinska Institute in Stockholm decided to take a closer look at that association. Their study involved 1,204 people with rheumatoid arthritis and 871 individuals without the disease. All participants were questioned about their smoking habits.
The researchers found that individuals who smoked at least 20 cigarettes daily for at least 20 years were more than 2.5 times as likely to test positive for the antibody called anticitrullinated protein/peptide (ACPA), a substance closely associated with the most common and severe form of rheumatoid arthritis.
In addition, investigators found that smoking accounted for 35 percent of rheumatoid arthritis patients positive for ACPA and 20 percent of the cases overall. Among individuals who were genetically susceptible to rheumatoid arthritis because they carry two copies of a specific allele (HLA-DRB1 SE), smoking was found to be responsible for 55 percent of ACPA-positive cases.
The Arthritis Foundation notes that individuals with the genetic marker HLA-DR4 may have an increased risk of developing rheumatoid arthritis. This substance is present in white blood cells and helps the body distinguish between its own cells and unwelcome invaders.
Although individuals cannot do anything about their genetic makeup, they can avoid certain risk factors. As this study shows, smoking is a major risk factor for rheumatoid arthritis, and fortunately, a preventable one. The study’s authors note that in all but the heaviest smokers, stopping smoking can reduce the risk of developing the disease.
Kallberg H et al. Annals of Rheumatic Diseases doi: 10.1136/ard.2009.120899