Scientists presenting findings of their research at a conference in the United States at the weekend said they found evidence that after four decades of decline, rheumatoid arthritis was on the rise among American women.
The research was the work of lead investigator Dr Sherine Gabriel, a rheumatologist at the Mayo Clinic, and other colleagues from the Clinic, and was presented last Saturday at the annual meeting of the American College of Rheumatology/Association of Rheumatology Health Professionals in San Francisco.
In the four decades leading up to 1994, the US saw a decline in the incidence of rheumatoid arthritis, but in the mid-90s the incidence and the prevalence of the disease started rising again.
The researchers based their findings on a study that included 350 adult patients of average age 57 from Olmsted County, Minnesota. 69 per cent of the patients were women.
Gabriel said:
“This is a significant finding and an indicator that more research needs to be done to better understand the causes and treatment of this devastating disease.”
Gabriel and colleagues said they didn’t know what the underlying cause was, but speculated it might be an environmental factor.
In the decade leading up to 1995 the annual incidence of rheumatoid arthritis among women in the US was about 36 women out of every 100,000. But this jumped to 54 women out of 100,000 in the following and most recent decade.
Among men the incidence has not changed: it remains at about 29 per 100,000, said Gabriel and colleagues.
The overall proportion of the US population that has the disease rose from 0.85 to 0.95 per cent, they added.
Rheumatoid arthritis is an autoimmune disease where cells of the immune system attack healthy joints. Why this happens is somewhat of a mystery, and some studies suggest genetic factors may play a role.
The main target is the synovium, the tissue that lines the joint. Chemicals released by the immune cells cause the tissue to swell and this damages cartilage and bone.
According to the American College of Rheumatology Research & Education Foundation, there are some 1.3 million Americans living with rheumatoid arthritis, the most common form of inflammatory arthritis. Of these about 75 per cent are women. While it can develop at any age, most people start to have symptoms in their 40s, 50s and 60s.
Although there is no cure, treatments exist that dramatically reduce symptoms by reducing joint pain and swelling, and if treated early, joint damage is minimal.
It is important that an expert does the diagnosis, to rule out other conditions that mimic rheumatoid arthritis, and make sure the right treatment is given for the individual patient.
Studies have shown that people treated early and promptly for rheumatoid arthritis feel better sooner and more often, and are more likely to lead an active life and experience less of the joint damage that often leads to replacement.
Sources: Mayo Clinic, American College of Rheumatology Research & Education Foundation.
Written by: Catharine Paddock, PhD.