By Susan Brady 27 May 2010
In the United States, the incidence of rheumatoid arthritis (RA) had steadily declined in both men and women from 1955 to 1994. That ten-year trend led researchers to assume that the incidence of the disease was continuing to drop in recent years. But studies of recent data found that from 1995 to the beginning of 2005, the number of American women with RA increased by nearly half from 36.4 per 100,000 in the previous 10 years to 54 per 100,000.
Research released today from the Mayo Clinic analyzed data and confirmed this upward tick, a rise of 2.5% from 1995 to 2007. RA among men, however, decreased during the same period of time.
Rheumatoid arthritis is an inflammatory disease that affects the entire system of the body. RA causes pain, stiffness, swelling and loss of motion in the joints. It is an autoimmune disease in which a person's immune system attacks the tissue that lines the joints, called the synovium, causing inflammation and tissue overgrowth.
Researchers have hypothesized reasons for the increase, with possible suspects including environmental or possibly hormonal factors, smoking, diet, alcohol consumption, coffee intake, and body mass index (BMI). A study is set to examine the effects that vitamin D has in preventing RA from developing.
Funded by Arthritis Research UK, research will be headed up by Dr. David Sansom and Dr. Karim Raza from the University of Birmingham. "We have recently found that vitamin D can have powerful effects on the type of immune cells which may cause rheumatoid arthritis…. This study will help us understand a lot more about how this happens. This is the first stage in considering whether vitamin D could be used as a treatment alongside or instead of current treatments.”
While there is no cure for arthritis, there are medications and techniques that can relieve the pain and inflammation associated with the disease. New medications are being approved, including the recent Simponi, the first self-administered, monthly, injected drug for moderate to severe rheumatoid arthritis. Simponi, also known as golimumab, has shown good success in post-approval trials.
Yoga can be a helpful, non-medical tool and you can also minimize inflammation through nutrition. Beneficial nutritive substances include foods with flavocoxid, fiber, omega-3 fatty acids, and conjugated linoleic acid.
Elena Myasoedova, MD PhD 1, Cynthia S. Crowson, MS 1, Hilal Maradit Kremers, MD MSc 1, Terry M. Therneau, PhD 1, Sherine E. Gabriel, MD MSc 1 2 *
1Department of Health Sciences Research, Mayo Clinic College of Medicine, Rochester, MN
2Department of Internal Medicine, Division of Rheumatology, Mayo Clinic College of Medicine, Rochester, MN
email: Sherine E. Gabriel (firstname.lastname@example.org)
- Correspondence to Sherine E. Gabriel, Department of Health Sciences Research, Mayo Foundation, 200 First St. SW, Rochester, MN 55905
Financial Disclosures: None
Ph: (507) 284-1696; Fax: (507) 284-1516
The National Institutes of Health
NIAMS; Grant Number: R01 AR46849
The National Institutes of Health; Grant Number: AR-30582
US Public Health Service
Objective: To examine the trends in incidence and prevalence of rheumatoid arthritis (RA) from 1995 to 2007.
Methods: To augment our preexisting inception cohort of RA patients (1955-1994), we assembled a population-based incidence cohort of individuals aged 18 years who first fulfilled ACR 1987 criteria for RA between 1/1/1995 and 12/31/2007 and a cohort of patients with prevalent RA on 1/1/2005. Incidence and prevalence rates were estimated and were age- and sex-adjusted to the 2000 US whites. Trends in incidence rates were examined using Poisson regression methods.
Results: The 1995-2007 incidence cohort comprised 466 patients (mean age 55.6 years; 66% female; 69% rheumatoid factor positive). The overall age- and sex-adjusted annual RA incidence was 40.9/100,000 population. The age-adjusted incidence in women was 53.1/100,000 population,(in men: 27.7/100,000 population). During 1995-2007 there was a moderate increase in RA incidence in women (p=0.02), but not in men (p=0.74). The increase was similar among all age groups. The overall age- and sex-adjusted prevalence on 1/1/2005 was 0.72% (95% CI 0.66-0.77) up from 0.62% (95% CI 0.55-0.69) in 1995 (p<0.001). Applying the 1/1/2005 prevalence to the US 2005 population, an estimated 1.5 million US adults are affected by RA. This is up from the 1.3 million reported previously.
Conclusion: The incidence of RA appears to be rising in women during 1995-2007 period. The reasons for this recent increase in incidence are unknown, but environmental factors may play a role. A corresponding increase in prevalence of RA was also found.