Inflammatory Arthritis and Bone Health
By Mary Anne Dunkin
Understand the factors that can weaken your bones when you have inflammatory arthritis. Learn ways to keep bones healthy.
You know that arthritis affects your joints and sometimes other organs like your skin or lungs. But how much thought have you given to its impact on your bones?
For example, 13 of 21 studies included in a 2016 review published in Seminars in Arthritis and Rheumatism identified low bone mineral density as a significant problem among people with psoriatic arthritis (PsA). When bones lose density they become weaker and more prone to fracture. In people with rheumatoid arthritis(RA), the fracture risk is roughly twice that of people without RA. That’s why taking care of your bones should be a priority for you and your doctor.
The Problem of Highs and Lows
Low bone density in people with inflammatory arthritis is not surprising to Stanley Cohen, MD, a practicing rheumatologist and clinical associate professor in the department of internal medicine at Southwestern Medical School in Dallas.
“Bone is a dynamic organ,” says Dr. Cohen. Healthy bone is constantly undergoing a process called remodeling. As cells called osteoclasts break down old bone, other cells called osteoblasts build new, strong bone. Having an inflammatory disease can disrupt this balance in several ways. High inflammation, low levels of calcium and vitamin D, lack of physical activity, and decreasing muscle mass can all play roles in bone health.
- High Inflammation. Cells involved in the inflammatory response make cytokines (proteins) including tumor necrosis factor (TNF) alpha, interleukin 1 and interleukin 6. These cytokines turn on the osteoclasts that break down bone. Stimulating the cells that break down bone results in a net loss of bone.
- Low Calcium and Vitamin D. Corticosteroids are sometimes used to control inflammation. These drugs, which are similar to cortisol produced by our bodies, negatively affect the metabolism of calcium and vitamin D needed for strong bones. The Seminars in Arthritis and Rheumatism review found that the ongoing use of corticosteroids was associated with lower bone density and the presence of erosions in some people with PsA.
- Little Exercise. Weight-bearing exercise – where the body’s weight is carried by the legs – stimulates the bone-building osteoblasts. If pain and stiffness make it difficult to exercise, your body may not produce enough osteoblasts to maintain optimal bone density.
- Increasing age. Advanced age and being a woman (particularly postmenopausal) both affect bone loss in the general population. Those universal factors compound the disease-related ones leading to reduced bone density.
- Falling Muscle Mass. Age-related bone loss often goes hand in hand with loss of muscle mass and strength, or sarcopenia. For example, a 2017 study of 95 women ages 50–75 published in the journal Reumatologia found that women with PsA had up to twice the rate of sarcopenia compared with age-matched controls. Sarcopenia was also associated with a 31% increase in the occurrence of disorders of bone mineralization. Together, these increase the risk of falls and possible fractures.
Biologics May Preserve Bone Density
If you have an inflammatory form of arthritis, proper treatment is important for preserving bone health and disease control, says University of Toronto professor and PsA researcher Dafna Gladman, MD.
Several recent studies suggest that by blocking inflammatory cytokines, biologics both dampen arthritis inflammation and preserve bone health.
A study led by Dr. Gladman and published in the July 2019 issue of Arthritis Research & Therapy reported that PsA patients taking biologics experienced better bone health than other study participants not using biologics. And a 2019 review article published in Clinical and Experimental Rheumatology concluded that biologics have positive effects on bone turnover and bone mineral density above and beyond what comes from just controlling the disease.
What You and Your Doctor Can Do
Together with your doctor, you can determine the best treatment option for your arthritis that can also have a positive effect on bone health.
- Vitamin D. Dr. Cohen recommends asking your doctor to check your levels of vitamin D, which your body uses along with calcium to strengthen bones. Depending on the test results, you and your doctor can determine if you need to increase your intake of vitamin D-rich or fortified foods, take a supplement or to take other actions.
- DEXA. Also, ask your doctor if you need a DEXA scan – a highly sensitive radiographic test for measuring bone density. The National Osteoporosis Foundation recommends the first DEXA scan at age 65. “But for people with an inflammatory disease we would do DEXAs at an earlier age,” says Dr. Cohen. If a DEXA shows low bone density, your doctor may prescribe one of several drugs approved to build bone or slow its loss.
- Calcium. A healthy diet that includes calcium-rich foods is good for bones and can help you to maintain a healthy weight. According to the National Institutes of Health, the recommended allowance of calcium for men and women, ages 19–50 is 1,000 mg per day. That amount increases to 1,200 mg per day for women ages 51–70 years. At age 71, both men and women need 1,200 mg per day.
- Lifestyle. Excess weight fuels inflammation that can attack bones. Lose weight if you need to. Research shows that smoking weakens bones and alcohol intake (more than one drink for women and two drinks for men daily) increases the risk of osteoporosis.
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Krajewska-Włodarczyk M, et al. Changes in body composition and bone mineral density in postmenopausal women with psoriatic arthritis. https://www.ncbi.nlm.nih.gov/pubmed/29332959
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Targowski T. Sarcopaenia and rheumatoid arthritis. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5442299/
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