People with diagnosed diabetes are nearly twice as likely to have arthritis, indicating a diabetes-arthritis connection.

Diabetes occurs when the body does not produce or use the hormone insulin sufficiently. Insulin shuttles glucose from foods into cells so it can be converted into energy. Without insulin, glucose remains in your blood (raising blood glucose levels), your cells create less energy and you feel fatigued.

What starts off as a hormonal problem can evolve into joint problems, in addition to the widely known cardiovascular problems.  

Diabetes causes musculoskeletal changes that lead to symptoms such as joint pain and stiffness; swelling; nodules under the skin, particularly in the fingers; tight, thickened skin; trigger finger; carpal tunnel syndrome; painful shoulders; and severely affected feet. After having had diabetes for several years, joint damage – called diabetic arthropathy – can occur.

Though they both share connections with diabetes, rheumatoid arthritis (RA) and osteoarthritis (OA) are related to the disease in different ways. Let's look at a few of the connections:

Autoimmunity and type 1 diabetes. Type 1 diabetes is an autoimmune disease, as is rheumatoid arthritis. In people who have type 1 diabetes, the body attacks the pancreas, the organ where insulin is made, just as RA attacks the synovial tissue lining the joints. Inflammation is the common culprit.        

Levels of inflammatory markers, such as C-reactive protein (CRP) and interleukin-6 (IL-6), which often are high in people with rheumatoid arthritis, also are increased in those with type 1 diabetes. A study of people who had type 1 diabetes for longer than five years shows an increase in tumor necrosis factor-alpha (TNF-a), another inflammatory marker often elevated in people with inflammatory forms of arthritis. Inhibiting TNF-a with drugs such as adalimumab (Humira), etanercept (Enbrel) and infliximab (Remicade) is the goal of treating arthritis and related conditions.

As scientists learn more about the roots of inflammation, some treatments for inflammatory arthritis may wind up helping to control other inflammation-related conditions. Researchers already are testing the possibilities.

Reducing inflammation with Remicade improved insulin sensitivity in people who had inflammatory diseases and were insulin resistant, according to a small study published in the journal Annals of the Rheumatic Diseases. And in a study of 70 people who had type 2 diabetes, the arthritis drug anakinra (Kineret) brought down the glucose level, improved function of the pancreas and decreased levels of CRP and IL-6.