Epidemiology of RA

I have many times mixed up different types of arthritis, rheumatoid arthritis, osteoarthritis, and regular arthritis. Generally I think of arthritis as effecting older adults, and thus think of it as a disease of aging. After so many years of using our bodies and especially our joints, they start to have problems, and that problem is arthritis. This, I found, is not true. 

There are many kinds of arthritis, listed below, with an image of the prevalence of some:

• Childhood arthritis (Juvenile Idiopathic Arthritis (JIA) is a kind of childhood arthritis)
• Fibromyalgia
• General
• Gout
• Osteoarthritis
• Rheumatoid arthritis (RA)
• Systemic lupus erythematosus
• Psoriatic arthritis
• Polymyalgia rheumatica

       

1. Clough JD. The Cleveland Clinic Guide to Arthritis. New York, NY: Kaplan Publishing; 2009.

3. Lawrence RC, Felson DT, Helmick CG, et al. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part II. Arthritis Rheum 2008;58:26-35.

4. Gelfand JM, Gladman DD, Mease PJ, et al. Epidemiology of psoriatic arthritis in the population of the United States. J Am Acad Dermatol 2005;53:573.

 5. Espinosa M, Gottlieb BS. Juvenile Idiopathic Arthritis. Pediatr Rev 2012;33:303-13.

6. http://rheumatoidarthritis.net/types-of-arthritis/

We can see the different kinds ranging from children to adults. Rheumatoid arthritis is seen in all ages and in both genders, and is most common in older adult women. Here is some additional epidemiological data on Rheumatoid arthritis:

• Annual incidence: 40/100,000 diagnosed each year
• Disease prevalence in Caucasians is 1%, varies in different populations between 0.1% and 5%.
• Women effected 2-3 times more often than men
• Peak onset 50-75
• Prevalence in females over the age of 65 is 5%
• Significant reductions in employment, productivity, and function with attendant negative economic impact
• Lifetime risk of RA in adults is 3.6% for women, 1.7 for men

Gender differences:

• It is perhaps in part due to the stimulatory effects of estrogen on the immune system, seen in increased risk in nulliparous women, remission of RA during the third trimester in pregnancy, and decreased testosterone levels in men with RA.
• It is unclear if in men changes in hormones are a result of chronic inflammation or if abnormal estrogen and testosterone levels are a risk factor for developing RA

You may ask how this data is gathered. You would be very smart, because I didn’t, and the answer is very interesting. The most current data on RA comes from the Rochester Epidemiological Project. They conduct population-based research in Olmsted County, Minnesota in conjunction with the Mayo Clinic (see, I’m sounding smart again!) With a high percentage of residents in the county participating, they can do statistical analysis to find the most accurate data to date on many diseases and outcomes. This is an 8 min video about the project.

Rochester Epidemiological Project:

Rheumatoid Arthritis can cause disability in those it effects, and because it is still unknown what causes it, there is no way to prevent it. Next we will look at the pathophysiology and risk factors for RA.

Sources:

1.     http://www.cdc.gov/arthritis/basics/rheumatoid.htm

2.     http://www-uptodate-com.offcampus.lib.washington.edu/contents/epidemiology-of-risk-factors-for-and-possible-causes-of-rheumatoid-arthritis?source=search_result&search=rheumatoid+arthritis+epidemiology&selectedTitle=1~150

3.     http://rochesterproject.org/