Is there a link between Rheumatoid Arthritis and Diabetes?
When you were in high school what was your favorite subject? Besides music, it was anything math-related for me. I didn't much care for words, which is ironic since now I spend time putting thoughts and information into understandable and relatable words. I preferred trigonometry, calculus, physics, even chemistry and algebra. Now I'm about to reveal how much of a mathematics geek I truly am.
Here's a word problem for you.
***** Diabetes affects nearly 24 million people in the United States (almost 8 percent of the population) according to 2007 prevalence data estimates released by the Centers for Disease Control and Prevention (CDC). Recent research reveals that prevalence of diabetes in the U.S. is 13.7% among men and 11.7% among women older than 30 years of age. Undiagnosed diabetes may range anywhere from 2.1-3.7% of the adult population.
***** An estimated 43 million people in the U.S. have arthritis or other rheumatic conditions according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a division of the National Institutes of Health. The more than 100 rheumatic diseases, characterized by inflammation and of loss of function in supporting or connecting structures of the body, are a more frequent cause of activity limitation than heart disease, cancer, or diabetes.
***** Rheumatoid arthritis is an inflammatory disease of the immune system which first targets the synovium, or lining of the joint, resulting in pain, stiffness, swelling, joint damage, and loss of function. Inflammation most often affects joints of the hands and feet and tends to occur symmetrically which helps to distinguish it from other diseases. The Arthritis Foundation estimates that 1.3 million Americans, or about 0.6 percent of the U.S. adult population, live with rheumatoid arthritis.
***** In 2008, the CDC released an analysis of data collected during phone surveys conducted in 2005 and 2007 as part of the Behavioral Risk Factor Surveillance System (BRFSS). Of nearly 800,000 persons who self-reported living with doctor-diagnosed diabetes, 52% answered yes to the question - _"Have you ever been told by a doctor or other health professional that you have some form of arthritis, rheumatoid arthritis, gout, lupus, or fibromyalgia?" _
***** The Arthritis Foundation reports a Diabetes-Arthritis connection with the following statement found on their website - "New research shows that people with diagnosed diabetes are nearly twice as likely to have arthritis - about 53 percent of people with diabetes also have arthritis."
The question to be answered is:
How many people in the U.S. live with both diabetes and rheumatoid arthritis?
a) 12.5 million people
b) 1.3 million people
c) 416,000 people
d) 3.4 million people
e) none of the above
What was your answer? Hopefully, it was E, none of the above.
It's important to remember that approximately 1.3 million people in the U.S. have rheumatoid arthritis, thus none of the answers could possibly be correct unless every one of us also had diabetes. However, the question remains -- how common is it to have both diseases?
What is the prevalence rate of an RA and Diabetes co-morbidity?
The comorbidity of diabetes mellitus (DM) and rheumatoid arthritis (RA) is little discussed. In fact there is hardly any research about it. I did locate a 1950 study by Klaus JÃ¤rvinen in the Annals of the Rheumatic Diseases titled "A Study of the Interrelations of Rheumatoid Arthritis and Diabetes Mellitus." This study looked at patients who were treated at the Third Medical Clinic at the University of Helsinki and in the medical wards of the Kivela Hospital during the 15-year period 1934-1948.
For this study, there were 1,008 rheumatoid arthritis patients and 766 diabetes patients. Within these groups of patients, 1.3% of the RA patients also had diabetes and 1.7% of the diabetes patients also had RA. Only 13 patients total were found to have both RA and diabetes, an occurrence which was no higher than would be expected in the general population. The author's conclusion was that these two diseases have no obvious tendency either to occur together.
A more recent study sought to compare risk factors for cardiovascular disease in patients with RA versus diabetes:"Rheumatoid arthritis versus diabetes as a risk factor for cardiovascular disease-- a cross-sectional study, the CARRE Investigation." There were 353 RA patients in the study. First, 10 people were excluded (six people with type 1 diabetes (6 people) and four people whose fasting blood glucose levels were unavailable). Another 49 were excluded because they either had type 2 diabetes or fasting plasma glucose levels higher than 6.1 mmol/l.
The study authors concluded that people with rheumatoid arthritis had comparable risk of cardiovascular disease to people with type 2 diabetes, and we well know how diabetes is a significant risk factor for heart disease.
Finally, one more study sought to examine the cross-sectional association between rheumatoid arthritis and diabetes in a population aged 60 or above in the years 1988-1994. Of 5,302 survey participants, 144 had rheumatoid arthritis and 24 of these participants also had diabetes. Thus 16.7% of those surveyed had both RA and diabetes. The authors conclude that there is no strong evidence of an association between RA and diabetes.
From this patient's understanding of the information presented above, it appears that there is no significant link between developing rheumatoid arthritis and diabetes. Although type 1 diabetes and RA are both autoimmune diseases, having one does not seem to increase the risk of developing the other. Good news.
Based on the information presented above, I'm going out on a thin limb to guestimate how many people in the United States might live with both RA and diabetes.
1.3 million people living with RA x approx 16% prevalence rate of diabetes =
208,000 American adults might live with an RA/diabetes comorbidity
But that's just my guess.