The Relationship Between Rheumatoid Arthritis and Osteoporosis and Factors Contributing to This Connection

Rheumatoid arthritis (RA) is an autoimmune chronic connective tissue disease that produces persistent systemic inflammation, with joint inflammation leading to function loss and joint destruction. It can finally lead to some serious systematic disorders, such as cardiovascular, pulmonary, skeletal, and psychological disorders. One of the most severe comorbidities of RA is osteoporosis (OP), which is a chronic metabolic skeletal disease leading to an increased risk of low trauma fracture, and many factors can play a role in increasing this association including treating RA patients with glucocorticoid over a long duration, chronic joints inflammation, calcium malabsorption, age of the patients, and genetics. Osteoporosis is characterized by microarchitectural deterioration of bone tissue and low bone mass. The most commonly used measurement for OP is bone mineral density (BMD) and DEXA (dual x-ray absorptiometry) Scans. Osteoporosis can result in devastating physical, psychosocial, and economic consequences. Still, it is often overlooked and undertreated, in large part because it is clinically silent; there are no symptoms before a fracture occurs. Epidemiological studies indicate that about 60-80% of RA patients have a comorbidity of OP. These two kinds of complex diseases may share some common genetic mechanisms and biological processes. For example, proinflammatory cytokines including TNF-α, IL-17, IL-6, and IL-1 have been reported to be closely associated with OP, and they also play important roles in the development of RA. Also, the inflammation in the joints increases bone absorption and makes RA patients susceptible to bone loss and osteoporosis development. One of the primary drugs recommended for the treatment of RA is a corticosteroid, glucocorticoid (GC). Both systemic corticosteroid and intraarticular corticosteroid are proven to be risk factors for developing secondary osteoporosis and osteoporotic fracture. The risk increases with the long duration of use and using a high dose. Longer duration and severity of RA were also indicated as independent risk factors for vertebral fractures. The American College of Rheumatology (ACR) recommended increasing the awareness of RA patients about BMD and getting DXA done for identifying a patient at risk of osteoporosis.