Women who are overweight or obese may be more likely than healthy-weight women to develop rheumatoid arthritis. These results were presented at the 2012 Annual Meeting of the American College of Rheumatology.
Rheumatoid arthritis (RA) is an autoimmune disease that affects an estimated 1.3 million adults in the United States. The condition causes pain, swelling, and stiffness of joints, and can also affect other parts of the body.
Factors that increase the risk of RA include being female, having a family history of RA, and smoking. Some studies have suggested that body weight may also play a role, but results have not been entirely consistent.
To further explore the relationship between weight and RA in women, researchers evaluated information from two large, ongoing studies: the Nurses Health Study and the Nurses Health Study II. Information was available about more than 230,000 women between the ages of 25 and 55.
Information about body weight was collected before any of the women were diagnosed with RA. Cases of RA were identified during subsequent years of follow-up.
Weight was assessed using a measure known as the body mass index (BMI). BMI considers both weight and height. A BMI between 25 and 29.9 is considered overweight, and a BMI of 30 or higher is considered obese.
For each study (the Nurses Health Study and the Nurses Health Study II), the risk of RA in overweight and obese women was compared with the risk in healthy-weight women.
- In the Nurses Health Study, overweight women had a 19% increased risk of RA and obese women had an 18% increased risk.
- In the Nurses Health Study II, overweight women had a 78% increased risk of RA and obese women had a 73% increased risk.
Although the magnitude of the increased risk varied by study, both sets of results suggest that excess body weight may increase the risk of RA in women.
Reference: Lu B, Chen C-Y, Hiraki LT, Costenbader KH, Karlson EW. Overweight and obesity increase risk of rheumatoid arthritis in women in a large prospective study. Presented at the 2012 Annual Meeting of the American College of Rheumatology. Washington, DC. November 10-14, 2012. Abstract 1608.