With obesity and rheumatoid arthritis (RA) becoming more common, the question is, could one have something to do with the other? For women, say researchers at Mayo Clinic, it appears there is a link. The medical records of 813 adults with RA and 813 adults in a control group were examined over the period 1980-2007. Roughly 30 percent of the subjects in each group were obese and 68 percent were women. RA cases rose by 9.2 percent from 1985 to 2007, the study found, and obesity accounted for 52 percent of the increase. Although the exact nature of the link between obseity and autoimmune diseases such as RA is not clear, the studys authors concluded, We know that fat tissues and cells produce substances that are active in inflammation and immunity. We know, too, that obesity is related to many other health problems. It adds another reason to reduce and prevent obesity in the general population.